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Bµsâ Sµ^Ý.IVIANSIIIP
irr
-
.ra,
A
Guide to
fiHfuiä"g³MA*"rP
Dear friend,
on bÕhalf of thÕ AdministrÐtivÕ CommittÕe of thÕ JSU
WÕlfarÕ Fund, plÕase al]ow us to Õxpress oursináÕre grÕetings
to our non-domiáilÕd spÕáial mÕmbÕrs onboard the vÕssels,
áovÕrÕd by JSU CollÕátivÕAgrermrnts. This guidebook was
designed for training sÕafarers and fostering their suááÕssors.
It is áruáial proáÕss for maritimÕ indusä to hand down
well-expÕriÕnáed navigation skill to thÕ future International
shipping in ordÕr to make a signifiáant áontribution to thÕ
fuß:rÕ developmÕnt and to fostÕr áompetent seafÐrers. It is Ð]so
an assÕt for maritimÕ indusä whiáh should bÕ handed ovÕr.
HowÕvÕr' in thÕ áontext of thÕ áiráumstanáÕ of the eduáation
for seafarÕrs and thÕ initiation of maritimÕ skill, it is
not nÕáÕssarily to say that it is dÕfinitÕly suffiáient for us
to take advantage of an opportunity to be instruátÕd by
well-expÕrienáÕd and áompÕtÕnt offiáÕrs at sÕa.
In viÕw of this issuÕ, I firmly bÕlievÕ that this book will
bÕ ÕffÕátivÕlã-luti|ized for training Ðnd dÕveloping of
futurÕ sÕafarers, and will makÕ mÕaningful áontributions
to thÕsÕ efforts'
FinÐlly, wÕ would likÕ to extend our sináere gratitudÕ and
appÓeáiation to everyonÕ involved in this projeát, Õspeáially
thÕ IntemationÐl ¼ÐrinÕrs ¼anÐgÕment Assoáiation of Japan.
Best rÕgÐrds.
Yoji Fujisawa
Áhairman,
AdministrativÕ CommittÕÕ of JSU
W.ÕlfarÕ Fund and;
PresidÕnt,
A1l Japan SÕamen,s Union
¼anÕuvÕring Capability of Ships
002
005
oo7
013
021
Ship Handling in Restriáted Waters
028
028
o29
In-Harbor Ship Handling
044
Ship Handling inWaves
}IÕteÞrÞlÞgã fÞr Safe NÐvigation in
µåtratropiáal and Tropiáal CãálÞnes (Storms)
Handling Þf Speáial.PurpÞse Ships
\I×ririmÕ Âraffiá SafÕtã Law
À rt Regul ati ons LÐw
l |l ài áÐl Si gnal s and ShapÕs
, t:l ßÕsÕ Lal r and RÕáommended Praáti áÕs)
rl ×J.l r ³i shi ng ArÕas and Types of Fi shi ng
i. ài áÐ| Fi shi ng MÕthods & GÕar
l |l ài áÐI Inl Ðnd SÕa Fi shi ng MÕthods
?'' i'tÐgÕ Di stri áts i n Japan
ifl( \ \bluntarv Traffiá SÕparation SáhÕmÕ
À ; h ]i shÕd: 0l -SÕptember.2002)
L ×i Õ| }Ior ement i n Mal aááÐ Strai t
: . B.R.\l. Bri Õfi ng)
l: 'ud \umbÕr: RÕlÐtionship bÕtwÕÕn Ship LÕngth and SpÕÕd
r PPµ\DI\
:i.i âi.1n Di Ðgranl for thá l vl aster)
070
086
096
112
116
124
140
'150
153
155
158
160
162
164
166
176
177
âIIµ Òµsâ sµßtvIANsIIIP
A Gui de to Shi p Handl i ng
PublishÕd by Japan Captains' Assoáiation (JCA)
KAI» áµNâRµ BLDG.' 5F
5,4-Áhome, Kohjimaáhi' Chiyoda-ku, Êkyo 102-008×' JAPAN
Tel : (8 1 )-3 -3 2 6 5 -664 1 F aå: · 26 5.87 1 0 URL : htä ://Www. captain.ofip l
Sponsor:
Administrative CommittÕÕ of JSU Welfare Fund
Production:
All Japan SÕaman's Union (AJSU)
Produátion, Publisheæ Ðnd SÕcondÐry Áopãright HoldÕr:
IntÕrnÐtional MÐrißÕrs ¼anagÕment Assoáiation of Japan (II}IMAJ)
°uthor Ðnd PrimÐrã Áopãright ltolder:
Jaàan Captainsi Assoáiation (JCA)
Copãright
All áopéight is resÕruÕd. No part of this publiáation èybe repÓoduáed, stored in Ð retriÕval systÕm, oI ffansmitted in my fom or by my mès,
ÕlÕátroniá, mÕáhmiáal, photoáopying, rÕáording Þr othÕryisÕ without thÕ prior wÓitten pÕmission of thr áoà}âight holdels (JáA Ðnd IM¼A».
Editorial CommittÕÕ
ChÐirperson Ðnd Supervisor: KohÕi OHÂSU, ProfÕssor, Tokyo Universify of¿{arine Sáienáe Ðnd Teáhnologã
CommitteÕ MembÕrs: TatëlãaG°¼oU, KawasÐki Kisen ºaishÐ Ltd.
Hiroki ¼°RUYAMA, Yoshiãâki KoToKæ NYK Line
¼Ðsato ¼IYAS°º°, ¼asanori IiAYASÝI' ¼itsui o.S.º. Line
SÕárÕtÐiat.. Yasu1.uki ¼oRI¼oTo, Pâesident, JCA
Takaãuki FURI,Y°' ¼anaging Director' JC°
ProduáÕr: YÐsushi N°K°¼LIRA, ChairmÐn, NautiáÐl TrÐinißg Systeès, Ißá.
I|/ritÕr.' Shihei NO¼UR°, µmÕrifus Professor, Yuge National College of ]l4arifime Teáhnology
ChiÕf Editor. Âbkayuki F[,RLÓYA' ¼anaging Direátoæ JCA
English ÁonsultÐtion.. Hidetoshi KAZ°¼A, President, lVinds, Ltd.
Daniel Fath, Langu.age Consultant
°rt Directioß & DÕsigß: ShunryÞ OTAGIRI' Art Direátor/DesignÕæ Shun-Ryo. GRAPI{
¼ieko ITo. Desisner
@ Èfv[AJ #
NlanÕuYering áapability of Shi
.ad-a
..
s
-::.::.:t.::-l
GÕnÕral
A ruddÕr is a dÕviáÕ tÞ áÞntrol thÕ horizontal motion of a ship. ÂhÕ áontrol foráÕ rxÕrtÕd by a ruddÕr at
thÕ stÕrrr of a ship árÕatÕS a momÕnt on thÕ ship that áausÕs thÕ ship to rotatÕ and to ÞriÕnt itsÕlf at an
anglÕ of attaák to thÕ flow.
RuddÕr ForáÕs and ¼omÕnts
Ang|e of attaák
Lift foráÕ
Drag foráe
ÂotaI rÕsuItant foráe
Center of pressure
NormaI foráe
Axial foráe
Fig.1.1 RuáldÕÓ lÞÓáÕ áomp¾nÕnts
Ð'.
L:
D:
F:
CP:
Fè:
Fâ:
002 A Gui de to shi p Handl i ng
LÕt us áonsidÕr a ruddÕr as a sÕparatÕ Êodã at an ang|e of attaák d to the flow vÕloáity.
ÂhÕ áombination of for.ward vÕloáity and anglÕ of attaák will induáÕ a áiráulation about the ruddÕr that
ln fi]Ón produáÕs a lift foráÕ L on thÕ ruddÕr duÕ to a diffÕrÕnáÕ in thÕ prÕssurÕ aáting on thÕ uppÕr and
lÞß'Õr surfaáÕs of thÕ ruddÕr.
In a rral fluid, drag foráÕ D áompÞsÕd of friátion and sÕparatÕ foráÕs, aáts on thÕ ruddÕr.
.\s shown in Fig.l-1 thÕ total rÕsultant fÞráÕ F acts at apoint ca|Ied thÕ áÕntÕr of prÕssurÕ CP.
Âhis may bÕ rÕsolvÕd into aljft áomponrnt L normal tÞ thÕ dirÕátion of motion, it:/;o a drag áomponrnt
D parallÕl to thÕ dirÕátion of motion, or into a normal foráÕ FN normal to thÕ ÞÕntÕr planÕ of thÕ rud-
der, into a axia| foráÕ FÂ parallÕl to thr áÕntÕr planÕ of thÕ ruddÕr.
SináÕ thÕ axial foráÕ Fâ is vÕry small comparÕd to thÕ notmal foráÕ FN, thÕ normal foráÕ FN is áon-
sidÕrÕd to rÕprÕsÕnt ruddÕr foráÕ that áontrols thÕ motion of thÕ ship.
In addition to thÕ ruddÕr area, the gÕomÕtriá propÕr1iÕs of thÕ ruddÕæ suáh as aspÕát ratio, sÕátion shapÕ
and profilÕ shapÕ, influÕnáe the áapability of thÕ ruddÕr to funátion as a sÕparatÕ body.
RuddÕr at thÕ Stern
.\ ruddÕr loáatÕd at thÕ stÕrrr is subjÕát to influÕnáÕ from thÕ hull and thÕ propÕllÕæ and thÕ inflow vÕ-
loáity to thÕ ruddÕr is diffÕrÕnt from ship vÕloáity' Tuming motion of a ship also áhangÕs thÕ inflow vÕ.
loáity and dirÕátion to thÕ ruddÕr. ThÕ addÕd vÕloáity of propÕllÕr raáe inárÕasÕs thÕ ruddÕr foráÕ both
at nÞrmal spÕÕd and at zero spÕÕd. ¼ÕanwhilÕ, thÕ wakÕ, disfurbÕd watÕr dragged along with thÕ ship,
dÕáreasÕs thÕ inflow vÕloáity to thÕ ruddÕr. In thÕ stÕady ahÕad manÕuvÕæ thÕ ruddÕr is in propÕllÕr
raáÕ and its effÕátivÕnÕss is good whÕrÕ magnitudÕ of thÕ ruddÕr forÞÕ is about Õqual to that of a sÕpa-
rate in a uniform flow
The fol|owing áases are often experienáed
duri ng i n-harbor shi p handl i ng:
Þ In thÕ aááÕlrrating manruvÕr (aááÕlÕrating ahÕad from
zÕro spÕÕd), thÕ ruddÕr of a singlÕ sárÕw ship is partiáu-
larly ÕffÕátivÕ, bÕáause in this áÞnditiÞn thÕ ruddÕr opÕr-
atÕs in thÕ disáhargÕ jÕt of thÕ propÕllÕr, whiáh has a
vÕry high vÕloáity at zÕro spÕÕd rÕsulting from thÕ large
s1ip ratio of thÕ propÕllÕr. For this fÕason' the tuming
ability is ÕxáÕllÕnt, and thus is oftÕn usÕd by thÕ ship's
opÕratÞr whÕn hÕ doÕs not wish to aááÕlÕratÕ ahÕad but
rathÕr to áhangÕ thÕ ship's hÕading.
Þ on thÕ othÕr hand, thÕ ruddÕr ÕffÕátivÕnÕss is pÞor dur-
ing a áoasting manÕuvÕr (dÕáÕlÕrating thÕ ship without
using rÕvÕrsÕ power). With thÕ propÕllÕr wind.milling
or loákÕd, thÕ ruddÕr doÕs not bÕnÕflt from thÕ propÕl-
lÕr's disáhargÕ jÕt' and, aááordingly, nÕt vÕloáity of flÞw
ovÕr thÕ ruddÕr is vÕry small. Fig,1-2 shows thÕ áompar-
ison of turning trajÕátoriÕs on Õaáh manÕuvrr.
Fig.1-2
Turning tâajÕátÞries on steady ahead,
aááÕlÕration and dÕáÕlÕration manÕuvÕrs
*Äastirrg tilfl*
(Full ahÕad * Stoà ÕnginÕ-)
&**efÕr*ti:×g tl*rr:
(Ship spÕÕd zÕrÞ * Full ÐhÕaä
Nornnal tærn
(Full ahÕad)
A Gæi de to shi p }l and|i ng | 00×
![fifi@fit ManÕuvering Áapability Þf Ships
r In thÕ stopping manÕuvÕr (dÕáÕlÕrating thÕ ship by usÕ of fuli lÕvÕrsÕ powÕâ), thÕ ruddÕr ÕffÕátivÕnÕss is Õx-
áÕptionaily pooæ thÕ propÕllÕr disáhargÕ jÕt bÕing opposÕd in dirÕátion by thÕ ship's vÕloáity ahÕad rÕlativÕ to
thÕ watÕr' HÕnáÕ, thÕ nÕt vÕloáity of flow ovÕr thÕ rrrddÕr is ÕåáÕptionally small. Fig.1.3 shows thÕ flow
around thÕ stÕrrr whilÕ stopping.
:ita,ilä;t;;ra:,lltt:.';lna,ll|;iiitrt t.rr, gttt,
i;l '..-;-
i :*==.*
::, ,
i -='.".-"
, ...*-.*--,*- ='""*.----.-, ,*-,+. *+ ,s .f :. i i .,, ' i .: *' , tr , ".' ....
1 '=-:"--=-.: "=**""'t"*+"''- .; -. ' "''".." *--u i i't, .=
." ... i
Ì.
tt-
ii -''*-.
;i '"'-.
!t
: ---
ä, '"-'=''-..
u '""=.--
it ''=.
il
t:
tt
::.
Vs
PropelIer inflow veloáity is áanáelIed
Fig.1-3 F1o\v pattÕr¿
ThÕrÕforÕ, it is important to notÕ that thÕ propÕllÕr's powÕrful disáhargÕ jÕt is indispensablÕ fÞr thÕ rud-
dÕr ÕffÕátivÕnÕss.
;::
s ::
"Â;.i
:. ,
s<
Rudder is in prope||er raÞe
004 A Gui de to Shi p Handl i ng
1.l RuddÕr 1.z FundamÕntal ManÕuvÕÓing ÁharaáteÓistiás
Aáfual ship manÕuvÕring pattrrns praátiáed undÕr various navigational ÕnvironmÕnts arÕ álassifird
broadly into two Þatrgorirs -- áoursÕ kÕÕping and ÕvasivÕ (ÕmÕrgÕnáy) manÕuvÕrs'
WhÕrr áonsidÕring manruvrring proárdurrs, suáh
as áoursÕ kÕÕping' áoursÕ Þhanging, and dÕ-
áÕlÕrating/stopping, thÕ following manÕuvÕr-
ing áharaáteristiás arÕ rÕquirÕd for ship han-
dling:
1. Âurni ng abi Ii ty
2. l ni ti al turni ng abi l i ty
3. Yaw-áhecking and áourse-keeping
abi l i ti es
4. Stopping ability
µaáh is briÕfly dÕfinÕd bÕlow:
1' Âurni ng abi l i ty
Âuming ability is thÕ mÕasurÕ of the abiliä to
turn thÕ ship using hard-ovÕr ruddÕr.
ÂhÕ rÕsults bÕing a minimum ..advanáÕ at 90"
áhangÕ of hÕading', and ..taátiáal diamÕtÕr',
dÕfinÕd by thÕ ..transfÕr at 180.áhangÕ of
hÕading.',
2. l ni ti al turni ng /
áourse changing abiIity
ÂhÕ initial tèrning ability is dÕfinÕd by thÕ
áhangÕ-of-hÕading rÕsponsÕ to a modÕratÕ
he]m in tÕrms of hÕading deviation pÕr unit
distanáÕ sailÕd.
lnitiÐ| turning abiIity = 0/Unit distanáe
Fig.1-4 Turring path of Ð ship
Âi me: seáond
Fig.1.5 Initiai turning aìi1jtã & ÕffÕát Þf Cb
â
o)
á)
Ä
Ñ
'.
í
t-
Begin steering 35" (Hard starboard)
O
Ä
o
Ä
,Ä
g
.s
'F
í
Ó
A Gui de to shi p ÝÐndl i ng
!@[sfl ManÕuvÕring Áaàability of Ships
3.2' Yaw-áheáking abi|ity
ThÕ yaw-áhÕáking ability of a
ship is a mrasurÕ of thÕ rÕsponsÕ
to áountÕr-ruddÕr appliÕd in a
áÕr1ain statÕ of turnins.
3-1. Course-keepi ng abi l i ty
ÁoursÕ-kÕÕpä abiliä is a mÕas-
èÕ of thÕ ability of thÕ ship to
maintain a straight path on a prÕ.
dÕtÕrminÕd áoursÕ without Õå-
áÕssive osáillations of ruddÕr or
hÕading.
5f,1, )
sffi)
Fig.1.7 Yaw-áhÕáking Ðbility
4. Stoppi ng abi l i ty
Stopping ability is mÕasurÕd by thÕ ..traák rÕaáh', and ..timÕ to dÕad in watÕr'' realized in a stop ÕnginÕ-
full astÕrn manÕuvÕr pÕrformÕd aftÕr a stÕady approaáh at full tÕst spÕÕd.
Ji-:µ .}
é
Fig.1-8 Stoppingability
Rudder mg|e * Þourse |ine +
Poor áourse.keepi ng abi Ii ty shi p
Case 1.
:f,l, )
These vessels use rudder frequent|y to maintain áourse.
Case 2. Good áourse-keepi ng abi |i ty shi p
Fig.1.6 CoursÕ-keeping aÌilitã
006 | A Gui de to Shi p Handl i ns
I
].2 FundamÕntÐl ¼atrÕuvÕÓing Áhalaáteristiás
l.×
Sèâßrnary of maneuverabilitã
Shaàe of ship
Flne ship
µat ship
]: · Þck Coeffi ái ent)
Smal l
Large
ldnd of ship
áontainer
Âanker
Bulk áarrier
- : Ði turni ng abi Ii ty
Nearly equal but fat ship turns
s|igtit|y faster thÐn finñ ship'
aí;rse-keeping ability
Good
Poor
-.,;rning ability
Poor
Good
!r:i= _]e above áriteria is app|ied generally eÅáept in speáial áases.
.:× i\Io ÕstablishÕd Standards for Ship ManÕuvÕrability (hÕrÕinaftÕr áallÕd ..thÕ Standards'') in DÕ-
.;::..bÕr 2002' where cf;tÕia of manÕuvÕring áharacteristiás to bÕ áompliÕd with are stipulatÕd. ThÕsÕ
.:-:ÕÓiÐ æ'ill bÕ rrfrèrd in thÕ following rÕlÕvant SÕátions 1.3 (Turning CirálÕ ManÕuvÕr)' 1.4 (Ship
l,{=iÕur.Õring TÕsts) and 1.5 (SpÕÕd Áontrol).
Cì = Vl (LppxÒxd)
ÄÒslDlä
ÒÒEµÆb
dÒEffi
F'ig.1.9 BiÞák áÞÕffiáiÕnt (Áì)
I
{--Âransfer ---}r
' -- ßrÓnlng tÕst rÕmalns an lmportant ptactr
::. :nÐnÕuvÕr that ships frÕquÕntly pÕrform.
--:.l it is suitablÕ for analãztng tÕst rÕsults
:Õ: tusÕ thÕ final phasÕ of thÕ furning path is a
;.-:J\.-statÕ manÕuvÕr.
ÂhÕ ThrÕe Phases of a Turn
.èÊÕn thÕ ruddÕr is dÕflÕátÕd and hÕld at a
1Õd anglÕ, thÕ tuming path of thÕ ship's áÕn-
:.: 0i sâavity is áallÕd thÕ turning áirálÕ. ThÕ
. - :ÓsÕ of thÕ turning motion may bÕ dividÕd
::.. thÓÕÕ phasÕs:
ÂÐbl Õ 1-1
TÐátical diameter (TD)
µxeáute position
Begin steering 35' (Hard starboard)
Approach phase
::Ð ;;.. lst phase
2nd phase
3rd phase (steÐdy turn)
L; Shi p l ength
á : áenter of steÐdv turni nq ái rá|e
Ò: steÐdy turni ng ;Ðdi us -
Ô: Dri ft Ðng|e
6: Rudder Ðng|e
Å TÐátiáa] diameter(TD): Fat ship *3L
Fi ne shi p*4L
Fig.1.10 Âr-èâing path Þf a ship
Phase 1 PhÐse 2 Phase 3
Remarks
Ináreasi ng
Steady
Steady
Ñ
-Ûi é
InÞreasißg
lnÞreasing
Steady
r
0 l náreasi ng
Steady
B
.iel
I nwaÓd
Outward
s.Õíd Steady
Decreasi ng
Steady
(Same RP¼)
A Guide to ship ÝÐndl.ßs ] 007
I
![![@!l ¼anÕuvÕring Capability of Ships
Âhe first phase
ThÕ first phasÕ starts at thÕ instant that thÕ ruddÕr is laid ovÕr and may bÕ ÞvÕr by thÕ timÕ thÕ ruddÕr rÕaáhes
its full deflÕátion anglÕ. During this pÕriod, thÕ ruddÕr foráe and momÕnt produáÕ aááÕleration and are
opposed solÕly by thÕ inÕrtia ofthe ship, bÕáause thÕrÕ has not yet bÕÕn an opportunity for a substantial dÓift
ang\e p or yaw ratÕ ³ to dÕvÕlop.
The seáond phase
ThÕ ship ÕntÕrs thÕ seáond phasÕ of thÕ fuming, With thÕ dÕvelopment of a drift ang|e B and a yÐw ratÕ ³
whÕrÕ the ruddÕr foráÕ and momÕnt beáomÕ fully operativÕ. The áruáial ÕvÕnt at thÕ bÕginning of thÕ sÕáond
phasÕ is thÕ árÕation of a inwardly direátÕd foráÕ towards thÕ áentÕr of thÕ tum' rÕsulting from thÕ drift anglÕ p.
µventually, inwardly dirÕáted foráe áausÕd by thÕ drift anglÕ áomes into balanáe with thÕ outwardly direátÕd
áÕntrifugal foráÕ of thÕ ship. (ThÕ bÕginning of thÕ steady phasÕ.) HowevÕæ in thÕ sÕáond phase of thÕ fum' as
shown in Fig.1-10' the path of the ship's ÞÕntÕr of gravity at first rÕsponds to thÕ ruddÕr foráÕ and tends to port
bÕforÕ the inwardly dirÕátÕd foÓáÕ grows suffiáiÕntly laÓgÕ. In spitÕ of this tendenáy of thÕ ship's áÕntÕr of
gravity, the bow usually remains to starboard ofthÕ approaáh áourse during thÕ ÕntirÕ Õntry phasÕ. (Kiák.)
The third phase
ThÕ sÕáond phasÕ of tuming Õnds with thÕ ÕstablishmÕnt of thÕ new equilibrium of foráÕs. WhÕn this Õquilibrium
is rÕaáhed, thÕ ship sÕttles down to a áonstant radius with áonstant drift angle
and rotÐtion. This is the third, or the steady phasÕ of thÕ èm.
ThÕ stÕady turning radius is dÕfinÕd by thÕ following rÕlationship: R=Y /r
FurthÕrmorÕ, thÕ steady tuming radius would be proportional to thÕ ship
lÕngth L and invÕrsÕly proportional to thÕ ruddÕr dÕflÕátion anglÕ Ñ whilÕ thÕ
drift angle p would bÕ dirÕátly proportional to Ñ.
Charaáteristiás of thÕ Tirrning Path
R: turni ng radi us (m)
V: ship speed (m/seá)
r: yaw rate (radian/seá)
A diagram dÕfining thÕ tuèr is shown in Fig.1-10. GÕnÕrally, a ship's turning path is characterizedbã
four numÕriáal mÕasurÕs: thÕ advanáÕ, transfeæ taátiáal diamÕtÕr and stÕady furning diamrtÕr.
ThÕ advanáÕ is thÕ distanáÕ of thÕ ship's áÕntÕr of gravity along thÕ original áoursÕ frÞm
áommrnármrnt of ruddÕr dÕflÕátion to thÕ point whÕn thÕ ship has furnÕd 90..
ThÕ transfÕr is thÕ distanáÕ from thÕ original approaáh áoursÕ to thÕ ship's áentÕr of gravity whÕn it has
tærnÕd 90".
ThÕ taátiáal diamÕtÕr is thÕ distanáÕ from thÕ approaáh áoursÕ to thÕ ship's áÕntÕr of gravity whÕn it has
turnÕd l 80..
ÂhÕ stÕady furning diamÕtrr is thÕ diamÕtÕr of thÕ ship's trajÕátory whÕn it has sÕttlÕd down to thÕ
steady turning motion.
ThÕ gâÕat majority of mÕráhant ships havÕ taátiáal diametÕrs bÕtwÕÕn thrÕÕ and four ship lÕnsths at
hard-ovÕr ruddÕr (35").
!08 I A Guide to Ship HÐndling
rÈ¿o StÐndards sti pu|ate the turni ng Ðbi Ii ty of the shi p as fol |ows:
l:; ×dlanáÕ should not ÕxáÕÕd 4.5 ship lÕngths (L) and thÕ taátiáal diamÕtÕr should not ÕåáÕÕd 5 ship lÕngths
':- . ruÓniÛ-s áirálÕ manÕuvÕr with maåimum ruddÕr anglÕ.
l *l 3 Standards :°dvanáe < 4.5L
Taáti áaI di ameter < 5L
F -:,1-i 1 shows thÕ position of thÕ ..pivot point'' in a stÕady fum,
:l"lÕâ:ninÕd by drawing a pÕlpÕndiáular from thÕ áÕntÕr of thÕ
è:,×'dr rurning áirálÕ to thÕ áÕntÕrlinÕ of thÕ ship.
.' 'r .rbsÕrvÕr on board a turning ship, it appÕars as if thÕ ship is
- - -;-.- -+ cL^+ -^;-+
- .è.ç at tl l al ÀU[l t.
l-:Õ .njstÐnáÕ bÕtwÕÕn thÕ pivot point P and thÕ ship's áÕntÕr of
::}'-".:ß G is ÕåprÕssÕd as GP=R sinf.
'.:r :ntlst ships thÕ pivot point is somÕwhÕrÕ bÕtwÕÕn Il4 L and
: l tilßr.ard of thÕ ship's áÕntÕr of gravity.
ç: .hÕ Õntry StagÕ of thr SÕáond phasÕ of thÕ fuin, thÕ ship's áÕntÕr of gravity tÕnds to skid outwardly
:-Ór thÕ original path as thÕ rÕsult of thÕ ruddÕr foráÕ. This phÕnÞmÕnon is known as..kiák'', and its
::.Ôâi tudÕ i s about 1/100 shi p l Õngth LatthÕ áÕntrrof gravi ty. HowÕvÕr, aS Shown i n Fi g.1-12,
--.j.. :'tñI¿ kiák (thÕ magnitudÕ of latÕral shift at thÕ stÕm tÕrminal) rÕaáhÕs lp to 1l7 of ship lÕngth at
:: .{J" áhangÕ of hÕadiæg in hard-ovÕr
:j'idÕÓ' ÁarÕ should bÕ takÕn rÕgarding
Û,::n }.iák.
\'ä -:J.. stÕÓn kiák áan bÕ usÕd to onÕ's advan-
:].t,:i -- dÕflÕáting thÕ ruddÕr towards a man
-Ó:fÞÐrd prÕvÕnts him from bÕing áaught in
.:: nÓÞpÕllÕr.
GP=R si nµ 1/4L<GP<1/×L
Center of
G : áenter of gravity
P : Pivot ooint
oiÙiÌÊ¡i'.r"
R : stñady turning radius
Ô : Dri ftang|e Fi g.1-11
Drift anglÕ and pir,Þt point
]!ÙiÀ₠6ñlii!6iiii, -
lglilgliigilÄgÄ.E:
Fig.1-13
AppliáatiÞn of stÕIn kák-1 (Williamson turn)
A Gui de to shi p Ýandl i ng 009
F.l s'1-12 StÕrâ
!ftfilfl ManÕuvÕring Áapabiliä of Ships
o Óistring net apàears sudden|y
Ä HarÞ port to avoid fishing net
Fig.1-14 Appliáation of stÕrn kiák-2
Howeveæ abrupt and largÕ ruddÕr dÕflÕátions should bÕ avoidÕd whÕn passing in álosÕ proximity of an-
othÕr ship at bÕrth or at anáhoæ sináÕ stÕm kiák may áausÕ áontaát with thÕ ÞthÕr ship.
Fig.1.15 Contaát áausÕd by stern kiák
CouplÕd Motions in Turning
Heel angl e i n a turn
ThÕ dÕflÕátion ofthÕ ruddÕr is intÕn-
dÕd to produáÕ motion solely in thÕ
yaw planÕ, but motions arÕ also in-
duáÕd by áross áoupling into thÕ ro11
planÕ, Ðnd thÕsr arÕ 1ikÕly to bÕ of
áonáern. HÕÕl ÐnglÕs induÞÕd by thÕ
ruddÕr áan be ÕstimatÕd by áonsider-
ing the hÕÕling momÕnts arising
from thÕ vÕrtiáal disposition of the
foráÕs. In thÕ first phase of a star-
board turn, the vÕrtiáal disposition
bÕtwÕÕn thÕ ruddÕr foráÕ and thÕ in-
Õrtial rÕaáfion of thÕ ship makÕs thÕ
ship hÕÕl to starboard (inward).
These hÕÕl anglÕs arÕ small Ðnd soon
finishrd. ForáÕs aáting in thÕ roll
planÕ for thÕ third phase of a star-
board tum are shown in Fig.1-16.
010 | A Guide to Ship HÐndIing
l.× TrrÓrring ÁiÓále ManeuvÕr
-.-lin*s momÕnt arising from thÕ vertiáal disposition bÕtwÕÕn the áÕntrifugal foráe and hydrodynamiá foráes
:×.kÕs rhÕ ship heÕ1 to port (outward).
l l u-s. betweÕnthefi rstandthÕ thi rdphasÕs of atum,hÕÕl angl ÕÞfashi páhangÕs.
.-:Õ sÕáond hÕel (outward hÕÕl) involvÕs a largÕ ovÕrshoot anglÕ bÕyond thÕ Õquilibrium valuÕ of thÕ turâ's
::-:'i phasÕ as shown in Fig.1.17'
r.:tlâÕntially dangÕrous situation Õåistsjust prior to thÕ áompletion ofthe first large hÕÕl to port. CarÕ should
:Õ :×kÕn when opÕrating ships with poor stability, as áapsizing may rÕsult.
'" ': tÓansiÕnt, largÕ heÕl oááurs in suáh a ship, the onlã safÕ aátion is to immÕdiatÕly, but slowly and áautiously,
1:;-láÕ thÕ rudder anglÕ and, at thÕ samÕ timÕ, rÕduáÕ spÕÕd as quiákly as possible.
Reduátion of speed in a turn
SrÕÕd reduátion in a turrr is largÕly a funátion oftèrning áirálÕ tightnÕss; that is, hull rÕsistanáÕ inárÕasÕ duÕ to
::Õ dÕr.ÕlopmÕnt of äift anglÕ and ãaw rate,
"i:r¡ ÀÓopÕllÕr ÕffiáiÕnáy is rÕduáÕd.
]*:-.Õ smallÕr thÕ furning diamÕtÕr, thÕ mÞre
::::d thÕ ratÕ of spÕÕd rÕduátion.
F]is.l.18 shows thÕ spÕÕd rÕduátion as a funá-
:r- i Lrf furning diamÕtÕr (âÞ)zsìip lÕngth (L).
i:..nr thÕ figurÕ it is known that thÕ smallÕr
:.:,; ßrming diamÕtÕæ the greatÕr thÕ rate of
;ÕÕd rÕduátion.
âÐáliáal diÐmeter/ship |ength (ÂD/L}
Fig.1-18 SpÕÕd rÕáluátion vs. tinal tuming
dialnÕtrr (TD/L)
InfluÕntial Faátors in Turning
l*Óning ability is influÕnáÕd by ÕxtÕrnal forÞÕs, Suáh as wind and áurrÕnt, and by thÕ dÕpth of WatÕr,
m:iáh will be ÕxplainÕd in Õaáh rÕlÕvant áhaptÕr' In this sÕátion, influÕntial faátors arÕ ÕåplainÕd in thÕ
;.tÕ of dÕÕn. unrÕstriátÕd watÕr and a áalm environmÕnt.
Shi p áonfi gurati on
,. :×t ship with largÕ bloák áoÕffiáiÕnt (Cì)
1æ5 good furning ability áomparÕd to a finÕ
;i:r rr.ith small Áì. A sÞhÕmatiá diagram is
.i l æâ i n Fi g.l -19.
Container, PCC i''Ó.:=
0.8
Bulker, VLCC
Fig.1-19 InfluÕnáÕ of Áì on turning ability
no
Ä
a nï
|Û -.-
p ^-(Ò U./
o
o- 0.6
!s
Ä n5
á'
st 0.4
'-
l-
0.7
0.6
I
á'L
o
&t
µ
$rt
o
Ä
t-
µudder "njtu ×s.
A Guide to ship Ýand|ins i 01 .l
!ft!ftfir ManÕuvÕring Capability Þf Ships
Underwater hull profile
Tuming abiliä is affeáted áonsidÕrably by thÕ undÕrwatÕr bow and stÕm profiles. ThÕ áut up at thÕ stÕrn
inárÕasÕs furning ability but dÕárÕasÕs áoursÕ-kÕÕping and initial turning abiliä'
on thÕ contrary thÕ dÕad wood at thÕ stÕrn inárÕasÕs áoursÕ-kÕÕping and initial turning abilitiÕs but dÕárÕasÕs
turning abiliä.
Tri m
ThÕ áhangÕ oftrim has thÕ samÕ ÕffÕát as a áhange ofunderwÐtÕr hull profilÕ. Trim by thÕ head rÕsults in a fa-
vorablÕ ÕffÕát on turning ability bÕáausÕ of thÕ forward
shift ofthÕ sidÕ foráÕ.s áÕntÕr ofprÕssurÕ, but an unfav-
orablÕ ÕffÕát on áoursÕ-kÕÕping and initial turning abili-
ti Õs.
on thÕ othÕr hand, trim by thÕ stÕrn rÕsults in an unfav-
orablÕ effÕát on turning ability, but a favorablÕ ÕffÕát on
áoursÕ-keeping and initial tuming abilitiÕs bÕáausÕ thÕ
side foráe's áÕntÕr of pressure shifts aftÕrwards. ThÕ in-
fluÕnáÕ of trim on furning ability is shown in Fig.1.20.
Fig.1.20 InfluenáÕ of trim Þn turning ability
Shi p speed
WhÕn a ship is running stÕadily at a áonstant sÞrÕw ratÕ, thÕre is littlÕ rÕlianáÕ on turning ability, and littlÕ
áhangÕ in thÕ sáalÕ of tuming áirálÕ.
As shown in Fig.l-2l, thrrÕ is littlÕ diffÕrÕnáÕ bÕtwÕÕn turning ability in Nav.-Full °hÕad and that of Slow
Ahead.
HowÕvÕr, as previously mÕntionÕd,
during a áoasting manÕuvÕr with
thÕ propellÕr wind-milling or
loákÕd, the ability to stÕÕI grows
Õxáeptionally worsÕ due to a loss
of propÕllÕr disáhargÕ áurrÕnt ovÕr
thÕ rudder.
on thÕ othÕr hand, during an aá-
áÕlerating manÕuvÕr' tuming abili
ä is ÕåáellÕnt duÕ to thÕ large slip
ratio of thÕ propÕllÕr. Âurning tra-
jeátoriÕs for Õaáh manÕuvÕr arr
shown in Fig.1-2.
400
Òudder ang|e 35. ]
. ...,,,,,,,1,..,..,.,,,.,,.-....
1200 (m)
o"'
á
-g
i 2L
J
Ä.'
.90
O
(m)
-1o/o 0 lo/o (trim/L)
Ârim bythe head<. +Ârim bythe stern
280'000.DWâ VLcc
Lpp:320 m
H/d: Deep water
Full Ioaded
012 | A Gui de to Shi p HÐndIi ng
I
Fig.1-21 ComparisÞn Þf turning undÕr stÕady propÕllÕr rotation
l -3 TuÓning Cirále ¼anÕuvÕr i l..{
.
.:.Õ StÐndards stipulatÕ that a turning tÕst is to bÕ pÕrformÕd to both starboard and port With 35.
:''j.jÕr' DÕtails of thÕ fuming áirálÕ manÕuÃet are dÕsáribÕd in SÕátion 1.3. ThÕrÕforÕ, ship manÕuvÕr
:5:.i othÕr than thÕ tuming trst arÕ disáussÕd in this sÕátion.
-- .ÛÕ past, thÕ ship manruvÕr tÕst was limitÕd to a fuining tÕst and solÕly for ana|ãzing tuming ability.
;.:rh thÕ dÕvÕlopment of large-sizÕd ships with large bloák áoÕffiáiÕnts, áoursÕ-kÕÕping and initia|
-:ring abilitiÕs havÕ bÕÕn recognized as important faátors in rÕgards to safÕ navigation.
Zig-zag ¼anÕuvÕr TÕst
T::.zÐg manÕuvÕr tÕst is thÕ manÕuvÕr whÕrÕ a known amount of hÕlm is appliÕd altÕrnatÕly to ÕithÕr
ii;Õ rr.hÕn a known hÕading dÕviation is rÕaáhÕd. Although lhe zig-zag manÕuvrr tÕst is simplÕ, it
:'- -. -Ós thÕ ovÕrall assÕssment of ship manÕuvÕrability duÕ to its proximity to aátual ship opÕrations.
lt-'lrrg thÕ 10./10" zig.zag manÕuver tÕst as an ÕxamplÕ, thÕ ÞpÕrating proáÕdurÕ of thÕ tÕst is
:â.:'×inÕd as follows; (Big,|.22)
o Ôtter a steady approaáh with zero Ãaw rate, the rudder is put over to .l0" to stÐrboard or port (first
íåeáute)
o,*vnen the heading has áhanged to 10. off the original heading, the rudder is reversed to 10. to
íort or starboard (seáond exeáute)
o Ôßer the rudder has been turned to port/starboard, the ship wi|l áontinue turning in the original
cireátion with a deáreasing turning rate. |n response to the rudder, the ship shou|d then turn to
lÞÓt/starboard. When the ship has reaáhed a heading of .l0" to port/starboard of the origina|
:ÞUrse, the rudder is again reversed to 10" to starboard/port (third eåeáute)
i..l.]2 shows a sáhÕmatiá diagram of thÕ 10"/l0" zig-zag tÕst, whÕrÕ thÕ following information
:'ri×inÕd from thÕ tÕst is shown:
;rÕ iÓst ÞvÕrshoot anglÕ
ár. :hÕ additional hÕad-
è. dÕr'iation following
:.Õ sÕáond ÕxÕáutÕ;
:j- sÕáond ovÕrshoot
.t'Ò::]Õ llz thÕ additional
-:. j i ng dÕvi ati on ³ol -
,::ßg thÕ thi rd ÕxÕ-
j:-:Õ: thÕ initial turning
:::.3 to sÕáond ÕxÕáutÕ
tÐ ×ßd thÕ timÕ to áhÕák
l l ^Ì.
ä - Heading ang|e
6 - Rudder angle
.rl First overshoot Ðngle
6Yz Second overshoot angle
StÐrboard
10"
o
10' .
Port
Fi g.1-22 ÂhÕ l 0./10.zi g-Za.q tÕst
A Guide to ship ÝÐndling l 0.l×
I
ÉgnÕuvÕring Áapability of Shiàs
The 20" l20. zig-zag tÕst is pÕrforrnÕd using thÕ samÕ proáÕdurÕ as abovÕ' using 20" ruddÕr anglÕs and
20. áhangÕ of hÕading, instÕad of l0" ruddÕr anglÕs and 'l0. áhangÕ of hÕading, rÕspÕátivÕly.
From thÕ ztg-zag manÕuvÕr tÕsts' ÕssÕntial information rÕgarding ship manÕuvÕrability is obtainÕd.
ThÕ Standards laã down áritÕria using thÕ tÕst rÕsults for initial tuming ability, and yaw-áhÕáking and
áoursÕ-kÕÕping abilitiÕs as follows:
(1) Initial turning abitity
With thÕ appliáation of 10. ruddÕr anglÕs to por1/starboard, thÕ ship should not havÕ travÕled morÕ than 2.5
ship lÕngths by thÕ timÕ the hÕading has áhangÕd by l0" from tì. o.iginut i"uáinï.
(2) Yaw-áheáki ng and áourse-keepi ng abi l i ti es
¾ ThÕ valuÕ ofthÕ first ovÕrshoot anglÕ in thÕ 10"/10" zig-zagtÕst should not ÕxáÕÕd:
(o tÞ. irr,v is lÕss than 10 seá;
@ zo" it ìÓl is 30 sÕá or more; and
@ 1s+o.s L/V) degrÕÕs' if L/V is 10 sÕá or more, but lÕss than 30 sÕá,
whÕrÕ L and V arÕ ÕxprÕssÕd in m and m,/sÕá, rÕspÕátIvÕly.
ÞThÕval uÕofthesÕáondovÕrshootangl Õi nthÕ10./t0. ztg-zagtÕstshoul dnotÕxáÕÕd:
Äzs" , if L/V is lÕss than 10 sÕá;
@æo". i ³Ll V i s 30 seá or morÕ; and
@ 1tz.s+Þ.zs L/V) dÕgrÕÕs, ifllV is l0 sÕá or morÕ, but lÕss than 30 sÕá.
L/V(10 sÕá
l 0 sÕá{L/V{30 sÞá
L/V}30 sÕá
0'{l Þ"
0l {(5+0.5ÅL/V).
a'{zo"
az{zs'
a,{{tl.s+o.l5 Å L^/)
az{4¾.
o ThÕ valuÕ ofthÕ first ovÕrshoÞt anglÕ in the20.l20" zig-zagtest shouldnot ÕxáeÕd 25".
ThÕ valuÕs of manÕuvÕrability indiáÕs K and T, to bÕ disáussÕd bÕloé arÕ áaláulatÕd from thÕ zig-zag
Praátiáal appliáation of thÕ tÕst will bÕ disáussÕd in thÕ sÕátion ManÕuvÕrability of a VÕry LargÕ Ship.
a,{25"
014 ' A Gui de to shi p Ýandl i ßg
\fiaßÕuverability IndiáÕs K and T
t': ::lÕ stÕady turning phasÕ, the rÕlation bÕtwÕÕn thÕ rudÕr anglÕ and thÕ stÕady tuming ratÕ is Õå-
:Ó:s.<Õd Ðs shown inFig,1-23, with áoÕffiáiÕnt K known Ðs thÕ turning indÕx..gain,'' ÂhÕ timÕ nÕÕdÕd
j:r:hÕ ruming ratÕ to dÕvÕlop to 6·0/o of stÕa-
:-, :uÓning ratÕ is ÕxprÕssÕd as Â. CoÕffiáiÕnt
..]³ .s l'nown as thÕ initial tuming indÕx, or
. :.]:-lÕ áonstant''' It is said that a |arge K valuÕ
:.Ó'-'i,JÕs a favoraÊ7e turrring ability. Faátors
l .Õ;Ólng thÕ valuÕs of fuining indiáÕs K and
â =Õ \1'atÕr dÕpth, draft, trim and ruddÕr anglÕ.
*í
{s
{B
.g
*
:5
{tt
r$
;3
ti;
Steady turning rÐtÕ 'i
tit&e ill
Fi g.l -23l:
Ship responsÕ to steppÕd input of rudder dÕflÕátion 'i
,tliral_riittltitllritittltäll]]1;r1111111,r,,rrttrt,rtttiiilti1::.::.' :1.111tilt:1111:],tlltitilltll,
:- ;urmbinations of largÕ or small valuÕs of K and T, manÕuvÕring áharaátÕristiás may bÕ álassifiÕd in forè
:jr:Õrns as shown inFig.|-24. HowÕvÕæ bÕáausÕ K (stÕady furning abiliä and 1¿ (initial turâing abili-
1" oÓ rÕsponsivÕnÕss to thÕ hÕlm) havÕ a áountÕrvailing naturr to Õaáh othÕæ most ships belong to onÕ
" ' :hÕ two pattÕrns shown in thÕ figurÕ (i.Õ., pattÕms B and Á).
S}tip A and Ship D bÕlong to typÕs whÕrÕ stÕady tuming abiliä and initial turning (rÕsponsivÕnÕss to thÕ
r:-ríl abiliä arÕ ÕithÕr good or pooæ and ships bÕlonging to thÕ abovÕ pattrms arÕ vÕry sáaráÕ'
s n ip B has good initial turning ability but poor stÕady statÕ fuining ability.
:.:lÕ high-spÕÕd áargo ships, suáh as áontainÕr ships, bÕlong to this pattÕm.
Slt-tip C has poor initial tuming abiliæz
ur gÞod stÕady statÕ fuming abiliä.
-.i ships, suáh as full-loadÕd WÁÁs
ß'd bulk áarÓiÕrs, bÕlong to this pattÕm.
Û\
fE
ft
^A
Ç
l{: C* large- good steady turning ability
.1³: c- smallt good initial turning ability
Fig.1-24 Four pattÕrâs Þf manÕuvÕrins áharaátÕristiás
x
x
o
x
o
o
K
â
A Gui de to Shi p HÐndl i ns l 015
I
E!fififl ¼ÐnÕur'Õring ÁapÐbilitr Þf Ships
Turning lag to nÕw áoursÕ
LÕt us áonsidÕr a ship is áhèrgng
áotèsÕ. DuÕ to thÕ rurning lag,
it is not possiblÕ to bring thÕ
ship onto thÕ intÕndÕd áoursÕ-
áhangin.Õ path if thÕ ruddÕr is
put o\.Õr rr.hÕn thÕ ship has
rÕaáhÕd thÕ áoursÕ.áhanging
point as shown in Fig.l-25.
Áourse-áhangi ng poi nt
Itt ll tl ll E,
l *"j,ê
Fig.1-25
CÞuÓsÕ.tuÓrri ng l Ðg
l l
ship Manruver TÕsts
WhÕn áhanäg Þoursl' thÕ rud.
der should bÕ put over brforÕ
rÕaáhing thÕ áoursÕ-áhanging
point, tÐking thÕ tuming lag into
aááount. ThÕ distanáÕ to nrw
áoursÕ is thÕ distÐnáÕ along thÕ
original approaáh áoursÕ, from
thÕ áommÕrráÕmÕnt of ruddÕr dÕ-
flÕáfion to thÕ áorrèÕ-áhanäg
àint. ThÕ relationship bÕtwÕÕn
thÕ áoursÕ-áhanging distanáÕ
to nÕw áourse and thÕ áoursÕ-
áhÐnging anglÕ is ÕxprÕssÕd
in Fig.1-2Ñ.
Fig.l-26
CÞuÓse- áhanging distanáÕ (new áouÓse distanáe)
ÂhÕ distanáe to a nÕw áoursr is affÕátÕd by thÕ typÕ of ship, thÕ ship's áondition and watÕr dÕpth.
!ft!!fl ManÕuvÕring Capability Þf Ships
NÕw CoursÕ KÕÕping Trst
ThÕ nÕw áoursÕ-kÕÕping tÕst providÕs information about thÕ timing of thÕ initial ruddÕr dÕflÕátion for
bringing the ship onto thÕ prÕdÕtÕrminÕd path' thÕ nÕ.iv áoursr distanáÕ, and thÕ timing of áhÕák hÕlm
for sÕtting thÕ ship onto thÕ nÕW áoursÕ.
This manÕuvÕr tÕst dÕmonstratÕs thÕ äpiáal rÞlÕ of initial turning and yaw-áhÕáking abilitiÕs, and is
usÕd for praátiáal manÕuvÕrs.
Âhe new áourse-keeping test is áarried out as foIIows:
l. ¼ovÕ thÕ ruddÕr to port 15".
2. WhÕn the áhangÕ of hÕading rÕaáhes thÕ ruddÕr rrvÕrse hÕading, Y z, ( V z:\0" , 20" , ×0" . . . ) from
thÕ initial approaáh hÕading, movÕ thÕ ruddÕr to starboard (áhÕák hÕlm).
3. WhÕn thÕ yaw rate wÕakÕns its intÕnsity duÕ to thÕ áhÕák hÕlm' rÕtærn thÕ ruddÕr amidships. WhÕn
thÕ fuming áÕasÕs and thÕ ship is sÕt onto a spÕáifiÕd áoursl' finish thÕ tÕst with thÕ data aáquisition
of thÕ nÕw áoursÕ anglÕ Y Ô and thÕ nÕw áoursÕ distanáÕ Xá.
4. RÕpÕat thÕ trst áhanging thÕ ruddÕr rrvrrsÕ hÕading Y z to 20" ,30. and Õtá.
5. RÕpÕat thÕ tÕst using an initial ruddÕr of starboard 1 5 ".
RÕpÕat stÕps l, 2 and · with ..starboard,' and ..port', rÕvÕrsÕd.
Fig.|-21 shows an ÕxamplÕ of thÕ nÕw áoursÕ-kÕrping tÕst.
When Yz=10"(20", ×0". . . . . . ).
Cheák helm ( 8 = -.t5") is deflected.
Vz: RuddÕr revÕrse heÐdi ng
V+: New áourse anol Õ
Rudder ami dshi ps
Rudder angIÕ
d=15"
l ni ti Ð| áourse
Fig.l-21
µxÕáuting proáÕdurÕ of nÕw áourse.keeping tÕst
Xá
018 | A Gui de to shi p Ýand|i ng
t-
I
I
Di stanáe to new áoursÕ
1.4 ShipManeuvÕrTests
The tÕst results arc aßartgÕd by plotting Xá versusYÔ andYÔ vÕrsusY2 árrrvÕs as shown in Fig.1-28,
ä whiáh thÕ timing of ÞhÕák hÕlm áorrÕsponding with the new áolrrsr anglÕ, and of initial rudder
ffiÕátion áan bÕ prediátÕd.
ftrexample, the following information is obtained from the figure:
.rfrÕn altering áourse to 40" to starboard ( Yl:40"), thÕ ruddÕr is dÕfleáted to stÐrboaâd |5o, at the
position 580 m (Xc:580 m: 2.1 L) short of thÕ plannÕd point of altÕring áourse
.rften the áhange of heading rÕaáhÕs 22" starboard(rÕvÕrsÕ heading anglÕYz 12"),
.. - ßrddÕr is dÕfleÞtÕd to port 15"
.âtsn thÕ yaw ratÕ wÕakÕns its intensity duÕ to thÕ áhÕák helm, thÕ ruddÕr is rÕtærnÕd amidships.
Ihs, thÕ ship is brouä orrto thÕ nÕw áotèsÕ path.
Xá1m1
1200
20" 40" 60"
Rudder reverse heading (Yz)
Fig.1.28 RÕsults of nÕw áoursÕ kÕeping tests
4L
120"
ct
-g
µ')
¡
Ä
o
P Bo"
(Ò
.µ
o
á'
o
í
o
(J
40"
Ship length 276 m
Rudder angle 15'
A Guide to shiÓ }|Ðndline | 019
!ft!fifl ManÕuvÕring CapÐbitity of Ships
Most navigators use the following proáedure to
áhange áourse safe|y.
Sample)
Note)
Þ Some |arge vesse|s suáh as VLCCs are required to use more than 20 deg rudder
angl e at the begi nni ng.
ÞÂurni ng rate shoul d be mai ntai ned wi thi n 10 deg/mi n for safe shi p handl i ng ex-
áept i n speái al áases.
Þ Ship-hand|ers are required to review their own ship's aátua| distanáe to new
áourse in every áondition.
New áourse
Steady as she goes
Mi dshi ps
About4to6ÞÐbl es
',li:i:r'i::i*rill!:rii::::::ili:r:i!tiilli:r1:i rilitlll:i} lltrrXlxl}!tl8rli1l|Xi:i}}l8X*}ili}}$i8l&*S?X}$3Xiäg1
020 | A Gui de to Shi p HÐnd|i ng
I
4-6 áables before way poinl
Sui tabl e turni ng rate
Âurni ng rate < 1o./ mi n
°void exáessive turning rate Âurni ng rate S 10./ mi n
Adiust áoursÕ on new áourse
5-15 deg before nÕw áourse
Headi ng on new áourse
Adjusling cÞurs* tÞ set rn new ₠eursr'
l..l Shi à N4al l áuvárTásts
Introduátion
Stopping, áoasting, baáking and accel.Õrating arÕ important ship manÕuvÕrs:
ÂhÕ first thrÕÕ arÕ partiáularly important for opÕrations in árowdÕd watÕrs or in proximity to
struáfurÕs. HowÕvÕr, thÕ intÕraátions bÕtwÕÕn hull and propÕllÕr during thÕsÕ manÕuvÕrs arÕ
áomplÕx.
Stopping is thÕ manÕuvÕr of dÕáÕlÕrating thÕ ship by usÕ of full baáking powÕr from any givÕn ahÕad
spÕÕd until thÕ ship áomÕs to rÕst. WhÕn disáussing stopping áapabilitiÕs, at lÕast two ahÕad spÕÕds
should bÕ áonsidÕred: a árash stop from ..full-ahÕad sÕa-spÕrd', and a stop from ,.harbor spÕÕd,' of
about 12 knots.
Coasting rÕfÕrs to dÕáÕlÕrating without using baáking powrr. ThÕ timÕ and distanáÕ rÕquirÕd for thÕ
ship to dÕáÕlÕratÕ to a speáified fraátion of thÕ initial spÕÕd is oftÕn of intÕrÕst in ship handling. It is
r Õrv impÞrtant for a ship handlÕr to dÕáÕlÕratÕ thÕ ship at thÕ lÕast sustainablÕ ahÕad powÕr at whiáh
thÕ ship will rÕtain stÕÕrabiliä.
Backing is thÕ manÕuvÕr of aácÕlÕrating thÕ ship from rÕSt to a givÕn astÕrn spÕÕd or distanáÕ.
Aácelerating is thÕ manÕuvÕr of aááÕlÕrating thÕ ship from thÕ rÕst or from any spÕáifiÕd ahÕad spÕÕd
:L} a hi ghÕr ahÕad spÕÕd'
ÂhÕ most important áharaátÕristiás of most of thÕsÕ manÕuvÕrs arÕ timÕ duration and distanáÕ from
initiation to áomplÕtion. To simplify analysÕs, we often assumr that thÕ ship travÕls a straight linÕ
duÓing thÕ manÕuvÕr.
Horr.ÕvÕæ during stopping or baáking manÕuvrrs of singlÕ sárrw or uni-rotating multi- sárÕw ships, thÕ
Óotation ofthÕ propÕllÕr(s) tÕnds to swing thÕ to port ifthÕ propÕllÕrs arÕ right-handÕd and to starboard
lf thÕy arÕ lÕft-handÕd.
ÂhÕsÕ tÕndÕnáiÕs áannot bÕ áompÕnsatÕd for with ruddÕr dÕflÕátions as dÕsáribÕd in SÕátion 1.1, and
thÕsÕ ÕffÕáts wi]l bÕ disáussÕd later in this sÕátion.
\\Êen the ship dÕviatÕs from a straight path during a stopping or baáking manÕuvÕÓ' thÕ distanáÕ
âar ÕiÕd is mÕasurÕd along its áurvÕd traák (traák rÕaáh).
ProjÕátions of this distanáÕ -- tÕrmÕd hÕad rÕaáh and|atera| dÕviation -- arÕ of thÕ grÕat importanáÕ as
àÕÓ³ormanáÕ áharaátÕristiás' (Fig. l -29)
l.-s
fiåÕd
quitÕ
A Guide to ship Ýandlins l 02.|
!fté ManÕuvÕring Áapability of Ships
Stopping
Introduáti on
Stopping is a manÕuver of interÕst primarily from thÕ point of viÕw
of avoiding áollision. WhÕn dÕáÕlÕrating thÕ ship by usÕ of full
baáking powÕr from ..full ahÕad sÕa-spÕÕd'' until thÕ ship áomÕs tÞ
rÕst, thÕ lÕngth of thÕ traák (traák rÕaáh) is áallÕd ..árash stopping
distanáÕ'' or ,.short stopping distanáÕ'', whiáh indiáatÕs thÕ most
important indÕå for stopping ability. ThÕ Standards dÕfinÕ thÕ tÕr-
minology usÕd in stopping tÕsts as shown in Fig.1-29. Stopping
abi l i ty i s mÕasurÕd by thÕ ,,track rÕaáh'' and ..ti mÕ to dÕad i n
watÕr', rea|ized in a stop ÕnginÕ-full astrrn manÕuvÕr pÕrformrd af-
ter a stÕady approaáh at full tÕst spÕÕd. LatÕral dÕviations arÕ also
of intÕrÕst' but thry arÕ vÕry sÕnsitivÕ to initial áonditions and wind
disturbanáÕs.
\/ Aátua|
Lateral
deviation
Shi p dead
tn waler
s
.t
fi
Propeller rotation
reverseo or
p|âán
reversed
order
Approaáh
áourse
Fig.l-29
DÕt]nitions usÕd in stÞpping tÕst
The IMo Standards stipulate the fo||owing stopping abi|ity áriterion to be áomp|ied with:
ThÕ traák rÕaáh in thÕ full astÕrn stopping tÕst should not ÕxáÕÕd l5 ship lÕngths.
HowÕvÕæ this valuÕ may bÕ modifiÕd by thÕ Administration whÕrÕ ships of largÕ displaáÕment makÕ
this áritÕrion impraátiáablÕ, but should in no áasÕ ÕxáÕÕd 20 ship lÕngths'
Operati ng el ements and shi p response duri ng stoppi ng maneuver
ThÕ timÕ history rÕáords ofpropÕllÕr thrust, ship spÕÕd' propÕllÕr rpm and distanáÕ travÕlÕd during a
stopping manÕuvrr arÕ shown in Fig.1-30.
n : propeller rpm
no : i ni ti Ð| ahead prope||er rpm
ná : áorrespondIng astern prope||er rpm
âp : prope|ler thrust
Tpo: initial propeller thrust
Âpá: áorresponding prope||er thrUst
U : shi p speed
Uo : i ni ti al shi p speed
S : distanáe trave|ed
so : stopping distanáe
tr :ti me to zero propel l er
rpm from astern order
Approxi mati on
Fig.1-30
TimÕ histÞry reáord of propÕllÕr thrust,
ship spÕÕd propÕllÕr rpm Ðnd distanáÕ travÕlÕd during a stÞpping manÕuvÕr
âp
Ñ
Àno
A
I
I
I
Ä|
i l
E+0
F
l
I
Y
E
<t)
022 | A Gui de to Shi p Handl i ng
1'5 SpÕÕd ÁÞntrÞl
As sÕÕn in thÕ figurÕ, thÕ dÕárÕasÕ ÞfpropÕllÕr rpm n
and propellÕr thrust Tp is rÕlativÕly quiák, and settlÕs
down to thÕ áorrÕsponding astÕrn propÕllÕr rpm ná
and baáking thrust Tpá, whÕrÕas ship spÕed U
dÕáÕlÕratÕs gradually and nÕÕds a áonsidÕrablÕ timÕ to
rÕaáh zÕro aftÕr thÕ gÕnÕration of stÕady baáking
thrust.
\ááordingly, thÕ ratÕ of inárÕasÕ of distanáÕ travÕlÕd
S is slow and rÕaáhÕs to thÕ stopping distanáÕ So 0
rr.hÕn thÕ ship áomÕs to rÕst.
Fig.1.31 shows an ÕxamplÕ of thÕ mÕasurÕd and
áomputÕd stopping distanáÕs at sÕvÕral initial speÕds
of a tankÕr in full load and in ballast áonditions.
It is known that thÕsÕ stopping distanáÕs arÕ áaláulatÕd vÕry aááuratÕly.
Influentia| faátors on stopping ability
.|. Coeffiáient of fineness (Cì)
WhÕn assuming thÕ two typÕs of ships having thÕ samÕ displaáÕmÕnt, fat ships with largÕ Cb' suáh as
tankÕrs or bulk áarriÕrs, áonstitutÕ áharaátÕristiá fÕafurÕs with longÕr stopping distanáÕs áomparrd to
finÕ ships with small Cb, suáh as áontainÕr ships' bÕáausÕ thÕ ship with lÐrgÕ Cb inárÕasÕs addÕd mass
in a longièdinal dirÕátion.
2. Astern thrust
NÕÕdlÕss to say, thÕ largÕr the valuÕ of áonstant thrust is, thÕ shortÕr thÕ stopping distanáÕ attainÕd.
Fig.1-32 shows stopping distanÞÕ vÕrsus thrÕÕ stagÕs of astÕm thrust: full astÕrn, half and slow astÕrn
thrust.
Fig.1-32
lnfluÕnáe of bÐáking thrust
slow half
Astern thrust
Ä
(J ?5,
á '--
.2
a 10L
á
'a
o-
(Û 5L
Ini ti al sPeed (knot)
Fig.1.31 MÕasurÕd and áomputÕd
stopping distanáÕ of a tankÕr
l ÍL
f; ror
.Ä
á
±5L
. Full load, measure
- FU|| |oad, áompute
- Òa||ast' áomputed
] Óul l toao
.n
Ballast
A Guide to ship ÝÐndling | 02i
E!fif, ¼anÕuvÕring Capabiliä Þf Shiàs
3. Types of power plants and propellers
ThÕ timÕ lag in rÕvÕrsing propÕllÕr rpm tÕnds to dilutÕ thÕ rÕsulting thrust inárÕasÕ. For largÕ tankÕrs,
stopping is rÕlativÕly insÕnsitivÕ to timÕ lag in rÕvÕrsing thÕ ÕnginÕ. on thÕ othÕr hand, it may bÕ im-
portant for rÕlativÕly light, high-spÕÕd ships, whÕrÕ thÕ thrust is largÕ áomparÕd to ship's mass. ThÕ for-
mÕr Õåplains why thÕrÕ is a slight diffÕrÕnáÕ in stopping distanáÕ bÕtwÕÕn thÕ largÕ ship installÕd with
a furbinÕ ÕnginÕ and onÕ with diÕsÕl ÕnginÕ, without bÕing affÕátÕd by thÕ diffÕrÕnáÕ of timÕ lag in rÕ-
vÕrsing thÕ ÕnginÕs. ThÕ lattÕr Õxplains why, for a rÕlativÕly small ship, thÕ stÞpping ability of a ship
ÕquippÕd with a áontrollablÕ pitáh propÕllÕr (CPP) is supÕrior a ship ÕquippÕd with a áonvÕntional
fixÕd pitáh propÕllÕr (FPP)' bÕ-
áausÕ thÕ timÕ rÕquirÕd to rÕvÕrsÕ
thÕ notáh of ÁPP is rÕlativÕly
shor1.
TablÕ 1-2
4. Di spl aáement and |oadi ng áondi ti on
Stopping distanáÕ and timÕ to stop
vary almost dirÕátly with a ship's
displaáÕmÕnt. Fig.1-33 shows thÕ
árash stopping distanáÕs of
VLCÁs, from whiáh it is also
known that thÕ stopping distanáÕ
of VLÁCs in full-load áondition is
approåimatÕly from 1.5 to 2.0
timÕs as long as that in ballast
áondition.
Ä 1El
ä
U)
- 50,000 100,000 1 50,000 200,000 250,000
Displaáement tonnage
Fig.1-33
Short stopping distanáÕs (vLÁC)
a ;Ful l -l oad
O : l n bal l ast
5. µxamp|es of stopping ability
TablÕ 1-3 shows thÕ rÕsults Þf sÕa trials on short stopping distancÕS ''S',
105.084 23× 14'7 Di esel l 5.5 ×'658
15.7
:..₠:l.1'.Eä$ä.:· :j.:::..¡..ä.-:=::::;::i]{.ii8+=.::i'i:â;säâ:i'µi.'i:i.jt.t.Ä.f,:.* i::'::4j?.₠'g;I+ Lâi;}ili4.¡i1:..ii'i$
279,989 319 20.3 Di esel 15.5 4,593 14.4
;-:.-:.'1;::·:....:i$i*1.;;:i::'i.::]i,:: l.:;.:'×19.]@.i.:. i::ii:::i'qä].i:.+ jlij:]?₠i:= 1.l-.*:ll.µ'ä*!!l=..:i
VLác 332'000 í20 24.Ò âurbi ne 14.8 3'241 10.1
TablÕ 1-3
ole áÐrrier
55,700 211 11.8 Di esel 16.0 1,875 8.9
ProdUát âanker
1;;r,,:;r'.=i.1Y.!Ee=
VLÞc
024 | ^ Gui de to Shi p HÐndIi ng
l.-5 SpÕÕd ÁÞrrtÓol
6. Âurni ng moti on duri ng stoppi ng
In this subsÕátion, tuÓning motion of a singlÕ-sárÕw ship with right-handÕd propÕllÕr during stopping
:âanÕuvÕr i s di sáussÕd.
.\s shown in Fig.1-34, whÕn thÕ propÕllÕr is rÕvÕrsing, thÕ diffÕrÕnáÕ in rÕaátion foráÕ ÕxÕrtÕd bÕtwÕÕn
thÕ uppÕr bladÕ and thÕ bottom bladÕ rÕsults in a nÕt foráÕ to port that tÕnds to áausÕ thÕ ship to turn to
starboard. (known as ..thÕ dirÕát ÕffÕát of propÕllÕr'',)
Sampl e of ri ght hand, si ngl e propel l er
Ahead rotating Astern rotating
*Reaátion foráe
Disáharge flow
Discharge current of àrope||er bottom stronger than top to depth of àrope|ler
Fig.1-34
Direát effeát of propÕllÕr
.\lso, as shown in Fig.1-35, thÕ intÕraátions bÕtwÕÕn hull (stÕm) and propÕllÕr disáhargÕ áurrÕnts pro-
duáÕs thÕ strong foráÕ to port that tÕnds to áausÕ thÕ ship to turn to starboard. (knows as ..thÕ indirÕát
ÕffÕát of propÕllÕr on hull.'')
Astern rotating
A Guide to ship ÝÐnd|ins 025
I
E!!!fl ManÕuvÕring Capabiliä of Ships
FurthÕrmorÕ, as stated in Seátion l.l, thÕ ruddÕr losÕs most of its Õf³ÕátivÕnÕss during stopping bÕ-
áausÕ thÕ nÕt vÕloáity of flow ovÕr thÕ ruddÕr is small.
GÕnÕrally, thÕ ship with right-handÕd propÕllÕr tÕnds to tum to starboard during stopping manÕuvÕr
duÕ to thÕ abovÕ statÕd diâÕát and indirÕát ÕffÕáts ofthÕ propÕllÕr.
In fact, numrrous stopping trials indiáatÕ that ships tÕnd to turn to starboard.
HowÕvÕæ bÕáausÕ ruddÕr ÕffÕátivÕnÕss and áoursÕ stability arÕ lost during stopping' thÕ turning dirÕá-
tion and its trajÕátory arÕ susáÕptiblÕ to suáh ÕxtÕrnal disturbanáÕs as wind and áurrÕnt, and arÕ usually
unprÕdiátab1Õ.
Fig.l-36 shows thÕ variations of traÞk rÕaáh in sÕa trials ofVLCCs.
Partiáularly' it is notÕd that many of thÕ ships in ballast áondition that arÕ vÕry susáeptiblÕ to Õxtrrnal
disturbanáÕs tÕnd to tum to port. ThÕrÕforÕ, thÕ utmost áarÕ should bÕ takÕn whÕn ÕxÕáuting thÕ árash
Stop manruvÕæ taking surrounding sÕa room and traffiá áonditions into aááÞunt.
Y./S
U :Shi p speed
UÞ: l ni ti aI speed
-0.6 -0.4 -0.2 0 0.2 0.4
Latera|dÕviation X./S
Fig.1-36 PositiÞn Þf ships dÕad in watÕr in árash stopping trials
At high spÕÕds and suf³táiÕnt sÕa room, it is said that furning of a largÕ ship is muáh supÕrior to
stopping for avoiding ahazard.
AdvanáÕ in a furn is muáh lÕss than hÕad reaáh in stopping and dirÕátional áontrol is maintainÕd. From
a slowÕr spÕÕd approaáh, thÕ stopping manÕuvÕr assumÕs grÕatÕr importanáÕ and thÕ furning manÕuvÕr
bÕáomÕs lÕss signifi áant.
026 | A Gui de to Shi p Handl i ns
Ship Handling in Restriáted WatÕrs
Ship handling in áonfinÕd watÕrs, partiáularly in narrow watrrways' has bÕÕn rÕáÕiving a great dÕal of
attÕntion in rÕáÕnt ãÕars. With thÕ ÕvÕr-inárÕasing sizÕ of ships, as ÕxÕmplifiÕd in tankÕrs and bulk áar-
riÕrs, potÕntia|hazards of áollision and gâounding aItracI attÕntion, and áontrol Õffors may rÕsults in
pÕrsonal injury and áostly damagÕ to both thÕ ship and thÕ surrounding ÕnvironmÕnt. An aááidÕnt áan
havÕ far-rraáhing ÕffÕáts' In rÕgard to manÕuvÕring pÕrformanáÕ' shallow watÕrs may bÕ dÕfinÕd as
thosÕ in whiáh thÕ ratio of watÕr dÕpth to ship draft is thâÕÕ or lÕss. At grÕatÕr ratios, shallow-watÕr Õf-
fÕáts on manÕuvÕring pÕrformanáe bÕáomÕ rapidly lÕss signifiáant as thÕ watÕr dÕÕpÕns. RÕstriátÕd wa-
tÕrs may bÕ dÕfinÕd aS nalâow áhannÕls Þr áanals, WatÕrways with vÕrtiáal or ÞvÕrhanging banks or
arÕas that ináludÕ piÕrs and breakwatÕrs whiáh introduár a substantial áhangÕ in manÕuvÕring áharaá-
tÕristiás or rÕquirÕmÕnts. obviously, most rÕstriátÕd watÕrs ináludÕ shallow watÕæ and many inÞludÕ
signifiáant áurrÕnts and tidÕs. In rÕstriátÕd watrrs, arÕas availablÕ for navigation arÕ limitÕd, furthÕr
áompliáating thÕ problÕms of manÕuvÕring and áontrol of thÕ ship.
fÄ
Reference Annex l,Chart showing Froude Number from ship length and ship speed
ThÕ FroudÕ NumbÕr is a dimÕnsiÞnlÕss numbÕr and has bÕÕn usÕd for matáhing thÕ similariff of mo-
tion bÕtwÕÕn a modÕl ship in tank tÕsts and an aátual ship undÕr way. HÕnáÕ, this numbÕr is usÕd for
áomparing and arranging thÕ ÕxpÕrimÕntal rÕsults of ships with various sizÕs and spÕÕds undÕr thÕ nor.
mativÕ mÕthod.
2) FroudÕ DÕpth l{umbÕr (ß'"n1
Âhis numbÕr is áallÕd thÕ FroudÕ DÕpth NumbÕr and is usÕd for áomparing thÕ ÕxpÕrimÕntal rÕsults of
ships with various spÕÕds and watÕr dÕpths undÕr normativÕ mÕthod.
028 | A Gui de to Shi p Handl i ns
I
1) FroudÕ NumbÕr (F")
Âhe Froude Number i s defi ned as
U: Shi p speed (m/seá)
g : Aááe|eration due to gravity (9.8m/seá,)
L: Shi p l ength (m)
Fnrr.Ui6H- Ý: DepthofWater(m)
Fn-U/
In a similar way to the Froude Number,
the following dimensionless number is defined as
2.l GÕnÕrÐl i 2.2 ParanreteÓs RÕlatÕál to ÁontlnÕd WatÕrs
] 2.3 ShallÞw-Water µffÕáts
µffÕáts on Hull SinkagÕ and ChangÕ of Trim (Squat)
WÊÕn a ship is proáÕÕding, surroètding watÕr is displaáÕd towards thÕ sidÕs and thÕ bottom of thÕ ship' ÕxÕrt-
rrrg thÕ flow of watÕr rÕlativÕ to thÕ moving ship. ThÕ prÕSsurÕ distÓibution that dÕvÕlops around thÕ shrp mov-
ing through watÕr distorts thÕ watÕr linÕ by raising thÕ lÕvÕl of thÕ hiä prÕssrèÕ rÕgions ahÕad of thÕ bow and
aft of thÕ stÕm, whilÕ, bÕáausÕ of thÕ rÕlativÕ vÕloáity inárÕasÕ. lorvÕring it along thÕ lÕngth of the hull, partiá-
ulaä amidships. Fig.2-1 shows an illustrafion of prÕssurÕ distribution of watÕr flow around thÕ hull.
<** Streamlines, showing water flow around the hull
Q Stagnation points where f|ow ve|oáity is zero
I
èÄPre@
Pressure increasing
+ri ro*o,o*rîi *éèe'ì
{ tlow deáelerating { Streamlines diveÓge
Pressure decreasing { Flow aááelerating { StreÐmlines áonverge
Fig.2-1
PrÕssurÕ distÓibution of water flow around thÕ hull
FlÞw veloáity ináreÐsing
Seabed
A Guide to ship ÝÐndlins lo29
I
!@@u Ship Handling in RÕstriáted WatÕrs
ConsÕquÕntly, thÕ ovÕrall ÕffÕát ofthÕ prÕssurÕ distribution is to árÕatÕ a loáal dÕprÕssion ofthÕ mÕan
lÕvÕl that áoináidÕs with thÕ ship and travÕls along with it. FurthÕrmorÕ, this drÞp in thÕ watÕr lÕvÕl is
áonáÕntratÕd amidships, whÕrÕ immÕrsÕd hull volumÕ is grÕatÕst, and thÕ ship will also movÕ bodily
downwards to maintain its full buÞyanáy, ináluding a áhangÕ of trim. This ÕffÕát is impÕráÕptiblÕ and
ièÕlÕvant in dÕÕp watÕæ but it bÕcomÕs signifiáant whÕn thÕ ship movÕs into shallow watÕr' whÕrÕ thÕ
rÕstriátion of flow bÕtwÕÕn thÕ hull and thÕ sÕabÕd wÕakÕns thÕ thâÕÕ-dimÕnsional flÞw towards thÕ
kÕÕl and thÕ two-dimÕnsional flow parallÕl to thÕ hull grows strongÕr. ThÕrÕfÞrÕ, thÕ mÕan watÕr lÕvÕl
around thÕ hull is dÕprÕssÕd fuithÕr aááompaniÕd by thÕ áhangÕ of trim, whiáh rÕsults in a signifiáant
rÕduátion of undÕr kÕÕl álÕaranáÕ' This phÕnomÕnon is known as ..squati' Fig'2-2 shows thÕ flow pat-
tÕrn, prÕssurÕ distribution and watÕr lÕvÕl around thÕ hull in shallow watÕr.
Deep Water
Stern
Bow
Shallow Water
Stern
Pressure
Water Level
+2
+1
-4
'V_21 t
+^
â!'
+2
âl
0
\^ ,/ I
-o / I
/
/
Fig.2-2 FlÞw àattÕßr, pÓÕssuÓÕ distribr-èiorr Ðnd áhangÕ o³ wÐter levÕl in shallow watÕr
030 I A Guide to Ship Handling
Fig.2-3 shows thÕ bow sinkagÕ (F.P.) and stÕrn sinkagÕ (A.P.) when proáÕeding in dÕÕp water (solid
line) and in shallow watÕr (áhain linÕ)'
The squat is áonspiáuous in shallow watÕr. Trim by thÕ hÕad is prominÕnt in thÕ low spÕÕd rangÕ, and
trim by thÕ stÕm in thÕ high-spÕÕd rangÕ. As thÕ FroudÕ NumbÕr approaáhÕs 0.25 (a ship of 300 m
lÕngth with its spÕÕd about 26 knots), thÕ bow of thÕ ship tÕnds to float, and thÕ stÕrn tÕnds to sink
abruptly. HowÕvÕæ largÕ-sizÕd ships usually navigatÕ shallow watÕr at stand-by spÕÕd, and most ships
arÕ áonsidÕrÕd to bÕ proáÕÕding with thÕ trim by thÕ hÕad. BÕáausÕ the squat is mainly rÕlatÕd to lÐrgÕ-
sizÕd ships with full-load áondi-
tions, it is important to obtain
thÕ amount of bow sinkagÕ, as
most of thÕ ships tÕnd to bÕ
trimmÕd by thÕ hÕad.
Fig.2.3 Bow and stem sinkagÕ
=r
F.P.
i l
w
F.P.
\ i l
\y
i l t
.P.
*" H/d = 1.813
Hld = ·7 '5
L: shi p l ength
H: water depth
d: draft
MerchÐnt ship: Fn { o.22
\
\
e"À. \
0.2 0.22
n?
å
J
dl
áÑ
å
á
%
+1,0
0
-1.0
-2.0
-3.0
-4.0
0.1
0.4
0.5 G',1
µi
ili
- - - -:-'
f.µ+ × {
reLi
reEfi@ Ship Handling in RÕstriátÕd WatÕrs
Fig.2-4 shows thÕ squat Õstimation áhart for a ship in áombinatiÞn with its lÕngth (L), and spÕÕd (U).
Instruátions: (PlottÕd bã brokÕn linÕ: bow sinkagÕ ofa 300 mÕter tanker with 17 metÕr draft proáÕÕding at 12 knots rn watÕr Þf22 mÕtÕâ dÕpth.)
16
15
14
13
gt2
o
5 11
'I
Þ
á)
8- to
Ä
""y->
{^oz
YY)
.#2,
//,,
YX.v
e
(
/,
{
7
,
,rry
.,/
7"
,
Y
raS
7
,
7
I
I
Fig.2-4
Squat Õstimation áhart
5
0.1
g '''
& 0.×
J
ì o.4
o)
(6
¡ o.5
Ä
Ð 0.6
áo
Ýlá=W".#ji?l](")
0.04
0.06 0.08 0.10 0.12 0.14 0.16 (Fn)
c µnter ship speed in knots. (U : 1 2 knots)
@ Draw para||el line to interseát appropriate ship |ength. (L: 300 m)
@ oroppeàendiáu|ar|inetointeÒeátäsáissÐoftheupperdiagrÐmtoobtainthecorrespondingFroudeNumber,(Fn:0.114)
@ Continue to draw perpendiÞular Iine to interseát appropriate water depth/ship draft. (H/d=1.3)
@ Draw para||e| |ine to interseát bow sinkÐge/ship Iength (%) to give bow sinkage as percent of ship |ength.
(BoW si nkage/shi à l ength (Lpp)=0.×2%, i.e', amount of bow si nkage=×00Å0.32%=0.96m)
o×2 | A Gui de to Shi p HÐnd|i ng
I
0.7
0.8
µffÕát on Hull RÕsistanáÕ and Ship SpÕÕd
WÊÕn a ship movÕs into shallow watÕæ ship spÕÕd is rÕduáÕd duÕ to inárÕasÕd wavÕ making rÕsistanáe
and thÕ dÕtÕrioration Þf prÞpulsivÕ ÕffiáiÕnáy.
From the results of speed trials, the following formula is
proposed for the áritiáal water depth affeáting hu|I resistanáe:
H<3y'8d
H: WÐter depth (m)
B: ship breÐdth (m)
d: Ship draft (m)
µffÕát on Turning Capability
WhÕn a ship is turning in shallow watÕæ thÕ fuming diamÕtÕr inárÕasÕs áonsidÕrably duÕ to thÕ blunt.
nÕss of hull rrsponsÕ at thÕ initial stagÕ of thÕ furn and thÕ inárÕase of thÕ furning momÕnt of rÕsistanáÕ.
Fig.2-5 shows thÕ rÕsults of 280,000-DWl ship lÕngth 320 mÕtrr VLCC tankÕr simulations in watÕr
dÕpth1.5 timÕs ship draft (tlld:l.5), ship spÕÕd l5.7 knots, full-loadÕd condition.
ln shallow watÕr, thÕ maximum advanáÕ inárÕasÕs up to approximatÕly l.4 timÕs, and thÕ taátiáal diam-
ÕtÕr inárÕases up to about 1.3 timÕs as áompared to tuming in dÕÕp watÕr, rÕspÕátivÕly.
280.000-DWâ vLáá
Lpp:320m
speed :15.7kt
Full-loaded
Rudder Ðngle ×5"
åship speed=Apprcaáh speed
Fig.2.5 Tuming áiâálÕ (áomparison bÕtwrÕn deÕp and shallow WatÕr arÕas)
(m)
ÄHId= oo
qg6=1.5
t:
A Guide to ship ÝandIins | 033
s:rÖalg!gt}!*mg
tE'llµI Ship Handling in RÕstriátÕd WatÕrs
AÞtual test
Rudder angle 35'
Fig.2-6 summarizÕs expÕrimÕntal data on tuming ratÕ.
280'Ä0.DwâvLáá
Lpp:320m
App]oaáh speed :7k
FulI-IoÐded
Fig.2.6 µffÕát of water depth on turning pÕrformanáe (280,000-DWT VLCC)
(TD =1391;..1 diameter)
A substantial inárÕasÕ in taátiáal diametÕr (turning diamÕtÕr) is shown in shallow watat (H/F|.2,).
In thÕ figurÕ, aÌout75Yo inárÕase in tÐátiáal diamrtÕr (furning diamÕtÕr) is observÕd as áomparÕd to thÕ
tactica| diamÕtÕr (turning diamÕteÓ) in dÕÕp water.
Turning áirálÕ in shallow watÕr gÕts biggÕr in thÕ dirÕátiÞn ofvÕssÕl sidÕ than advanáÕ.
And thÕ samr effÕát on'wake is observÕd in áoasting furn and aááelÕration tærn in shallow watÕr.
This áhangÕ in manÕuvering áharaátÕristiás is very important from thÕ viewpoint of maneuvÕring safÕ-
ä duÕ to ináÓÕasing importÐnáÕ of manÕuvÕring ability in shallow watÕr, suáh as in harbors and othÕr
rÕstriátÕd WaterwaÃs.
0×4 | A Gu.do to Ship Haßdling
I
tm)
2.3 Shallow-WÊtÕr µf1êáts
RÕáognizing thÕ Signs of Squat
- ship's officer on watáh wi]l notice the fo11owing tÕndÕnátÕs in thÕ ship's behavior when the ship
-..lllÕs into shallow watÕÓ:
.. Hu1l rÕsistanáÕ is inárÕasÕd Ðnd thÕ ship bÕgins to slow down as it bÕáomÕs affÕátÕd by squat.
]' .\s shown inFig.2-7, thÕ divÕrging wavÕ pattÕtâ appÕars to widÕrr as thÕ FÓoudÕ DÕpth NumbÕr
i µnì) i s i nárÕasÕd.
.]. ÂhÕ álosÕ proåimity of thÕ propÕllÕr to thÕ sÕabÕd tÕnds to áÓÕatÕ grratÕÓ hull vibration.
SpÕÕd is thÕ most influÕntia] faátor govÕtâing squat. so slowing thÕ ship will havÕ thÕ most immÕdi-
atÕ ÕffÕát in rÕduáing squat and improving áontÓol ovÕr thÕ ship, providÕd thÐt stÕÕragÕ way is main-
tai nÕd.
WatÕr deptlr a»d Wavá pattÕr.n
h,*=
ti ur\.*=
ullsH = U. (
Þ Reduáe speed to
regain áontrol of ship.
Þ°bnormal hul l
vibration is observed.
Fig.2-7
S**t$*êÐJ
¾.99
Serious
A Guide to Ship Handtins I 035
!@fi!fi! Ship Handling in RÕstriáted \lÊtÕrs
RÕquirÕd UndÕr KÕÕl ClÕaranáÕ
For safÕ navigation in shallow watÕæ it is ÕssÕntial to keÕp suffiáiÕnt álÕaÓÐnáÕ bÕtwÕen the ship's bot.
tom and thÕ sÕabÕd dÕpÕnding on thÕ áÞnditions of thÕ ship, the ship,s manÕuvÕÓability and thÕ áondi-
tions of thÕ sÕa area. This margin, known as..UndÕrKÕÕl ClÕaranáÕ (lKC),'' is dÕfinÕd as shown in
Fig.2-8.
Under Keel Clearanáe ( UKC) = (Gharted water depth) + ( Height of tide)-(Ship draft at rest)
Fig2.8 DÕfinition of undÕr kÕÕl álÕaranáÕ (JKC)
The fo|lowing faátors should be taken into aááount when determining UKC:
1. Hull sinkage and áhange of trim
WhÕn navigating shallow wateæ thÕ amount of bow sinkagÕ should bÕ kÕpt in mind as ships tÕnd to
bÕ trimmÕd by thÕ hÕad.
2. Sinkage of the fore and aft perpendiáulars, and bottom bilges due to ship osáillation
WhÕn thÕ enáountÕrÕd wavÕ pÕriod synáhâonizÕs rvith a ship's natural period of pitáh or rol1, thÕ
amount ofsinkagÕ should bÕ takÕn into áonsidÕration for fÞrÕ and aft pÕrpÕndiáulars or thÕ bottom
bilgÕs.
3. Aááuracy of áhÐrted depth
ThÕ following is thÕ intÕrnational standard for pÕrmissiblÕ Õrror in survÕying:
Þ Permissible error of 0.3 m for Water depth of 20 m or less
Þ Permissib|e error of 1'0 m for water depth between 20 m and .|00 m
ThÕrÕforÕ, thÕ abovÕ Õrrors in áhartÕd dÕpths should bÕ takÕn into áonsidÕration.
5 | A Guide to ship Ýandljng
4. Meteoro|ogiáaI and oceanographiá áonditions
. one hPa (one mili-baä rise in atmospheriá pressure depresses water Ieve| by approximate|y one áentimeter
.Whentheshi páomesi ntoaseaarÕaof seawaterdensi ty P2Irom anareaof seawaterdensi tyP1
the amount of the change in draft ld is expressed by:
'\. ,1 dr: initial ship's draft at sea water density, p1
Ôd=dl. + (+.fi cb: shi p,sb|oákcoeffi Þi ent
1,.w ' ln 2 ' cw: ship,s Water àIane area áoeffiÞient
or
Ôd=l .025. (1 l p,.1 IP,') W/âPá y,"?,*::.J:::lll"*
Navigators shou|d remember the foIlowing formuIa Ðnd vaIue.
Âhe formu|a gives approximate sinkage (ám) per 0.001 of áhange of density.
adp*0.001 .W/âPá
ldp : Sinkage per 0.001 change of density
ln the áase of VLCC'
adp*1.5 ám (ful l.l oad condi ti on)
DrÐft 20.01m at density 1.025.'.Draft 20.04 at density 1.023 (ld i ÐdpX2)
. Surplus margins should be taken for the áharaáter of the sea bottom, whiáh is áonsidered to be 60 ám
tor roákã bottom, 30 ám for sand bottom.
5. Examples of regulation and áriteria for standards
ThÕ µuropÕan MarinÕ Pilot Assoáiation (µ¼PA) has laid down thÕ following áritÕria to bÕ áompliÕd
with rÕgarding undÕr kÕÕl álÕaranáÕ (UKC):
Gondition
Open sea
Outer harbor
l nner harbor
ThÕ IMo stipulatÕs thÕ following rulÕ for a dÕÕp draft ship (having a draft of 15 mÕtÕrs) and a VLCC
(a tankÕr of 150,000-DWT or morÕ) passingNlalacca and SingaporÕ Straits:
. VLCCs and deep water vessels require an under keel álearanáe (UKC) of at least 3.5 meters at all
times during the entire passage through the Straits of galacca and Singapore.
.:.,, UKC..,.
2 20o/o dratl
> 15% draft
> 10% draft
UKá>3.5m
A Guide to ship Ýand]in" l o,, ]
EtrtrÐ Ship Handling in RÕstÓiátÕd WÐtÕrs
Bank effÕát
If a ship is proáÕÕding alÞng thÕ áÕnterlinÕ of a áanal whosÕ áross sÕátion is áonstant and symmÕtriáal
about its vÕrtiáal áÕntÕr planÕ, thÕn thÕrÕ is flow syrènÕtry port and starboard and thÕ ship is subjÕátÕd
to no yaw momÕnt or sidÕ foráÕ.
HowÕvÕæ whÕn thÕ ship is proáÕÕding álosÕ to onÕ sidÕ of thÕ áanal as shown tnFig.2-9, thÕ inárÕasÕ
in thÕ vÕloáity of flow betwÕÕn thÕ hull and thÕ nÕar wall áouplÕd with dÕáreasÕd vÕlÞáity of flow bÕ-
twÕÕn thÕ hull and thÕ far wall árratÕs a foráÕ that draws thÕ ship towards thÕ nÕar wall (suátion foráÕ).
¼ÕanwhilÕ, displaáÕd water mass is aááumulatÕd bÕtwÕÕn thÕ bow of thÕ ship and thÕ nÕar wall, gÕnÕr-
ating a high watÕr region. This high watÕr rÕgion (i.Õ. high prÕssurr rÕgion) árÕatrs a rÕpulsivÕ fÞráÕ tÞ-
wards thÕ far wall at thÕ
boé sÕtting up a momÕnt
that tÕnds to swing thÕ
bow towards thÕ far wall
(a bÞw out momÕnt).
]\Û>0
___t___
CenterIine of áhanneI
Fig.2.9 Bank ÕffÕát
With a small amount of drift anglÕ, thÕ ship will run ÞbliquÕly on thÕ ship.s path paÓallÕl to thÕ árntÕr.
linÕ of thÕ áanal' maintaining thÕ Õquilibrium of thÕ sidÕ foráÕs and momÕnts áÓÕatÕd bã thÕ drift mo-
tiÞn, bank ÕffÕát and ruddÕr dÕflÕátion, as shown in Fig.2-10.
µ=+ l^ due to rudder :::.j... :]Û.+ due to dritt ang|e E+ Ô^ due to bank etfeát B: drittangte
-t
I
tl
M : bow out moment
F : suátion foráe
7 : deviation from centerline
Channel wall
(1)
Òunning strÐight
(21
Starboard rudder
(3)
start of BÐnk effeát
(4)
Drift motion
µquiIibrium áondition
I A Guide to ship ÝÐnd|ing
Channel wall
Fig.2.10 µquilibrium áondition whilÕ pasSing a ádnal
ÂhÕrÕforÕ, thÕ áhrák hÕlm should bÕ dÕflÕátÕd towards thÕ nÕar wall to áontrol thÕ turning momÕnt gÕn-
ÕratÕd by thÕ drift anglÕ' HowÕver, a ship navigating a áhannÕl is in a situation of unstablÕ Õquilibrium,
and off-áÕntÕr áoursÕ maintÕnanáÕ áannot Ìe reailized mÕrÕly by dÕflÕáting áonstant ruddÕr anglÕs and
holding it fixÕd. For this puÆposÕ, whÕn a diffÕrÕnáÕ is dÕtÕátÕd for thÕ antiáipatÕd Õquilibrium áondi
tion, thÕ ruddÕr should bÕ dÕflÕátÕd to áoèÕát thÕ diffÕrÕnáÕ. By áontinuing suÞh stÕÕring, thÕ ship's path
may bÕ kÕpt parallÕl to thÕ áÕntÕrlinÕ of thÕ áanal. ThÕ mÕan dÕflÕátion of thÕ ruddÕr may bÕ rÕgardÕd as
thÕ áhÕák hÕlm' Fig.2-11 shows ÕxpÕrimÕntal rÕsults of rÕquirÕd áhÕÞk hÕlm to maintain off-áÕntÕrlinÕ
áoursÕ undÕr Õquilibrium áonditions with áhangÕs in water dÕpth. The absáissa shows thÕ ratio of dis-
tÐnáÕ ofláÕnteâline to ship brÕadth. In all áasÕs, Õquilibrium dift angle was relativelã small. It is said
that, with a maximum ruddÕr anglÕ of *·5o, a rÕsÕrvÕd ruddÕr ang|e of 20 dÕgâeÕs or so is rÕquirÕd for
thÕ safÕ ship handling in áonfinÕd WatÕrs. Aááordingly, thÕ allowablÕ áhÕák helm is limited to + 15"for
a ship with a maximum dÕsignÕd ruddÕr anglÕ of *35.. For this rÕasÞn, it is dangÕrous for a ship to
proáÕÕd through a path ÕxáÕssivÕly rÕmotÕ from thÕ áÕntÕrlinÕ ofthÕ áanal.
6 1Òudder Ðngle1
H/d
1.2
_o
20
-1.0
1.5
'1.9
l+W+l
Fig.2-11 RequiâÕd áhÕák hÕlm to maintain off-áÕntÕrline áoursÕ
WhÕn navigating shallow watÕr with an inálinÕd sÕabÕd athwart thÕ ship's beam, and for thÕ samr rÕa-
son as proárÕding álosÕ to onÕ sidÕ of a ÞhannÕl, a suátion foráÕ is árÕatÕd that draws thÕ ship towards
thÕ shallowÕâ sidÕ, and a bÞw-out momÕnt swings thÕ bow towards thÕ dÕÕpÕr sidÕ'
It is rÕportÕd that thÕ ÕffÕát of sÕabed inálination on áoursÕ kÕÕping is surprisingly grÕat, and that Ð sig-
nifiáant amount Þf ruddÕr dÕflÕátion is rÕquirÕd to maintain áoursr.
ThÕrÕ Õxist not a fÕw harbor-approaáh áhannÕls with sÕabÕd inÞlinations, wherÕ áarÕ should bÕ takÕn
during transit.
A Guide to shià Ýandling l
I
!@!@@ Ship Handling in RÕstriátÕd WatÕrs
IntÕraátion BÕtwÕÕn Two Ships
ClosÕ passagÕ of two ships and thÕ rÕsulting hydrodynamiá intÕraátions bÕ-
twÕÕn thÕ two arr opÕrationally important for situations suáh.as ovÕrtaking
or mÕÕting in a rÕstriátÕd áhannÕl, rnanÕuvÕring to avoid áollision, and
passing a ship moorÕd adjaáÕnt to a narrow áhannÕl. IntÕraátion in thÕ áasÕ
of mÕÕting (ships moving in oppositÕ dirÕátions hÕad on or nÕarly so) rare-
ly áausÕs problÕms as thÕ ships usually pass eaáh othÕr rÕlativÕly quiákly
and thÕrÕ is insuffráiÕnt timÕ for thÕ prÕssurÕ systÕms to áhangÕ in any sig-
nifiáant way. Most áritiáal situations arisÕ whÕn onÕ ship is ovÕrtaking the
othÕr and thÕ pÕriod of álosÕ proximity is rÕlativÕly long. Aááording to thÕ
rÕsults of modÕl tÕsts, touáhing and áollision aááidÕnts arÕ áausÕd by thÕ
supÕrposition Þf thÕ following faátors:
1. Both ships are making high speed and the speed differenáe between the
shi ps i s smal l.
2. Both ships are in an overtaking situation and have suffiáient time to interaát;
this differs from a meeting situation.
3. Both ships are running paral|e| with á|ose passage.
4. Both ships are navigating shal|ow Waters or restriáted Waters that are sus-
áeptibIe to interaátion.
I lnteraátions between two similÐr-sized ships in an overtaking situÐtion
Fig.2-|2 shÞws a diagram of foráÕs and momÕnts with thÕ rÕlativÕ position
of thÕ two ships whÕn ship B is ovÕrtaking ship A in a naßow áhannÕl.
ThÕ following two rÕgions may áausÕ a dangÕrous situation;
. When the bow of overtaking ship B overlaps't/4 to 1/3 of its length with the
stern of ship A, dangerous foráe moments towards the other ship are áre-
ated. (When abreast, the ships are drawn together by bodi|y suátion amid-
ships while bow-out moments and repulsive moments arise in both ships.)
. As ship B moves further ahead of A, ship A abruptly áhanges the direátion
of moment from ..bow-out'' to ..bow-in'', and, with a drawing foráe to ship
B, the vessls are at risk of touáhing.
To prÕvÕnt the dangÕr induáÕd bã ship intÕraátions, it is nÕáÕssary to rÕduáÕ
spÕÕd (iÕss than 10 knots), and to kÕÕp a suffiáiÕnt latÕÓal sÕparation dis-
tanáÕ of at lÕast onÕ ship lÕngth in thÕ parallÕl run.
,*â) ffi
trffi
'¿
l ol
êt]
tfr
µl
è
5À Turni ng moment
ä Bodily suátion
i; áhange in resistanáe
Fig2.|2 IntÕraátions bÕtwÕÕn twÞ ships of similaÓ sizÕ
040 | A GuidG to ship Ýand|ing
2.4 µtÂeáts of Narow ChannÕls
p lnteraátion between a tug (or Ð small áraft) and a large ship
WhÕn thÕ tug is ovÕrtaking thÕ largÕ ship to áhangÕ station from thÕ stÕrn to thÕ bow, the tug is affÕátÕd
by intÕraátion áonsidÕrably morÕ than thÕ largÕ ship. ThÕ tug is moving in watÕr flow that is dominatÕd
by thÕ strÕamlinÕs of thÕ prÕssurÕ fiÕld surrounding thÕ largÕ ship.
Fig.2-13 shows thÕ illustration of thÕ foráÕs and momÕnts working on thÕ fug whÕn thÕ tug is áhanging
station from thÕ strm to thÕ bow.
From thÕ figurÕs, thÕ following is known:
o Âhe tug approaáhing the stern of the |arge ship wi|| experienáe suátion foráe and bow.in (towards the
large ship) moment.
The rudder is to be def|eáted outwards. (Fig.2-13, (l) and O)
. When the tug is approaáhing abreast of the |arge ship' the tug will experienáe suátion foráe and bow-
out moment, and the rudder is to be defIeáted inwards. However, the suction foráe and bow-out
(against the large ship) moment are relatively weak. (Fig.2-13, @)
Þ When the tug is approaáhing the bow of the |arge ship' the tug wi|| enáounter ináreasing pressure and
an inárease of engine output is required to overcome the resistanáe barrier. Due to the greatly increased
suátion foráe and bow-out moment, enhanáed inward rudder def|eátion is required. (Fig.2-13,@)
o At the moment the tug moves ahead of the |arge ship' suátion foráe áhÐnges rapid|y into repu|sive
foráe and bow-out moment into bow-in moment. Âo áope with the bow-in moment, the rudder is to
be def|eáted outward. ln áase of untime|y switáhing of rudder def|ection, the tug.s bow wil| be turned
to the bow of the |arge ship, whiáh may resu|t in áoIIision. (Fig.2-13, o)
Fig2.13 Interaátion bÕtwÕÕn a tug and a largÕ shlp
A Guide to shin Ýandline | 041
!ftfisft Ship Handling in RÕstriátÕd WatÕrs
ll lnteraátion between moored and passing ships
As shown in Fig.2-14, thÕ áharaátrristiá fÕaturÕs of the intÕraátions Þn thÕ moorÕd ship arÕ summarizÕd
as ³ol l ows;
o The |ongitudinal forÞe has two peaks in opposite direátion - the first forward, the seáond afterward.
Þ The |atera| force is áharaáterized by initial repu|sion, foI|owed by attraátion between the ships and re-
pulsion again at the end of the passage.
. The yawing moment goes through four phases.bow repu|sion, bow attraátion, bow repu|sion and bow
attraátion.
200
8000
Ñ
Ä
µ
µ
o
Il -
á
µ
o
-1 00
-200
c r20 140 160 1
₠-..+ *
Time (seá)
Î....+
Ö+
Fig2-14
160 180
a mÞorÕd ship
The foráÕs and yaw momÕnt on thÕ moorÕd ship arÕ direátlã proportional to thÕ sizÕ and squarÕ of thÕ
spÕÕd ofthÕ passing ship, and invÕrsÕly proportional to thÕ watÕr dÕpth and latÕral sÕparation distanáÕ.
BÕsides the hydrodynamiá intÕraátion bÕtwÕen two ships, thÕ motion of thÕ moorÕd ship is influÕnáÕd
by thÕ wavÕ gÕnÕratÕd by thÕ passing ship. Partiáularly, thÕ ÕffÕát is áonspiáuous in surgÕ motion, and
involvÕs thÕ dÐngÕr of rÕnding mooring ropÕ and of damagÕ to the ship's sidÕ duÕ to áontaát with thÕ
wharf. As dÕsáribed abovÕ, thÕ ÕffÕát grows strongÕr as thÕ surrounding watÕr dÕpth bÕáomÕs shallow-
Õr, the ship passes at a fastÕr spÕÕd and with a smallÕr latera| sÕparation distanáÕ.
ThÕrÕforÕ, partiáularly in shallow WatÕrs, thÕ passing ship should keÕp thÕ latÕral separation distanáÕ as
broad as possiblÕ' and kÕÕp its spÕÕd as slow as possiblÕ whilÕ maintaining stÕÕrage way'
042 | ^ Guide to ship ÝÐndling
I
-wt1wwf,
In-Harb
GÕnÕral
RÕáÕntly, thÕrÕ has bÕÕn an inárÕasÕ in thÕ following typÕ of aááidÕnt: thÕ anáhor and anáhor áablÕ run
out to thÕ bittÕr Õnd whÕn thÕ anáhor is lÕt go from thÕ hawsÕ in a dÕÕp watÕr anáhoragÕ; thÕ aááidÕnt
oááurs bÕáausÕ thÕ wÕight of thÕ anáhor and áablÕ and thÕ momÕntum dÕvÕlopÕd by thÕ frÕÕ.fall ÕåáÕÕd
thÕ áapaáity of thÕ brakÕ. FurthÕrmorÕ, aááidÕnts involving vrssÕls lying at anáhor áontinuÕ to oááur.
Most of thÕsÕ arÕ thÕ rÕsult of dragging anáhor, and áonáÕtn drifting, áollision or grounding.
Anáhoring safÕly to prÕvÕnt thÕ abovÕ-mÕntionÕd aááidÕnts is disáussÕd in this sÕátion.
PrÕparation for Anáhoring
WhÕn anáhoring, prior invÕstigation of thÕ following áonditions for anáhoragÕ is rÕquirÕd:
1. Direction and strength of wind and áurrent
2. Depth of water
3. Âype of seabed (Seleát a type of seabed with good anáhor ho|ding áharaáteristics)
4. Loáation of |ee.shore, shoals, or hazÐrds suáh as submarine áab|es and other obstaá|es
5. Maneuvering room for approaáh
6' Swinging room after anáhoring
7. Conditions affeáting visibility' weather and
áurrents
Routing and spÕÕd rÕduátion plans on thÕ
Way to thÕ anáhoragÕ arÕ to bÕ madÕ, and thÕ
anáhoring mÕthod and approximatÕ lÕngths
of áablÕ to bÕ paid out should bÕ dÕáidÕd in
advanáe.
ThÕ following arÕ typÕs of anáhoring mÕthod'
as shown in Fig.3-1.
Riding to
two anáhors
ry. Wry
l l
l l
\P
\/
I
Mooring
Riding to
a single anáhor
O44 I A Guide to Ship Handling
l
Fig.3-1 AnáhÞringmÕthods
ThÕ riding to a singlÕ anáhÞr is thÕ most áoßrmon mÕthod, but thÕ othÕr two aááÕptablÕ mÕthods --
mooring or riding to two anáhors -- should bÕ usÕd whÕn wÕathÕr and áurrent áonditions demand.
OnáÕ thÕ mÕthod has bÕÕn áhosen, thÕ nÕxt dÕáision involvÕs whÕthÕr to anáhor to starboard or port.
Finally, prÕparations arÕ madÕ for lÕtting go anáhor. WhÕn riding to a singlÕ anáhor, thÕ following
Õmpiriáal standards arÕ givÕn for thÕ rÕquirÕd lÕngths of áablÕ to bÕ paid Þut:
Preparations for |etting go anáhor.
AftÕr thÕ trial run Þf thÕ windlass, thÕ following proáÕdures arÕ rÕquirÕd for making thÕ anáhor ÓÕady for let-
ting go: (sÕÕ Fig.3-3)
. µngagÕ thÕ áablÕ holder and thÕ pin for firmly seáuring lÕvÕr.
. RrmovÕ the anáhor lashings.
. RÕmovÕ thÕ áhain stopàÕâ upon áonfirming it is frÕÕ fâom any loaä a áon-
dition that requirÕs thÕ stoppÕr to bÕ sÕáurÕd at rÕst by thÕ sÕÞuring pin.
Þ RelÕasÕ the brakÕ and walk baák (out) thÕ áablÕ. (..Wa1k-baÞk''
mÕans lÕtting out áable using a gÕarÕd windlass.)
. Walk baák the anáhÞr to thÕ ..áoák.bill'' áondition or into thÕ watÕr
dÕpending on statÕ of anáhoragÕ. WÊÕn walking baák thÕ anáhor
into thÕ watÕr, ship speed should be rÕduáÕd to a rangÕ áonsidÕred
safÕ for lowÕring thÕ anáhor into the watÕr.
Fi g.3-3 wi ndl ass
. SÕt thÕ brakÕ firmly, disengagÕ the áablÕ holdÕr and sÕt thÕ pin for thÕ sÕárÓing lÕvÕr to thÕ disengage position.
ThÕ windlass is rÕady for letting go anáhor by frÕÕ-fall, when thÕ Ðnáhor is hÕld solÕly by the windlass' braking foráÕ.
. The opposite anáhor should bÕ rÕadiÕd and set on standby in prÕparation for an ÕmÕrgÕnáy.
o If thÕ ship is loadÕd with inflammablÕ liquid or gas' a water-flushing system for thÕ hawsÕ should be prÕ-
parÕd. ThÕ watÕr wiil bÕ usÕd to prrvrnt sparks áausÕd Ìy anáhoring opÕrations.
. In addition to anáhoring prÕparations Þn thÕ forÕáastlÕ, pÕrsonnÕl on thÕ navigation bridgÕ arÕ rÕquiâÕd to
makÕ prÕparations for usÕ ofthÕ Õáho-soundÕr and thÕ spÕÕd mÕter for thÕ puràosÕ ofmÕasuring watÕr depth
and ship's hÕadway, rÕspeátivÕly'
80
-
Ä
fr60
5
-a-40
Ä
o
20
@ Japanese standard:
. Normal anáhoring
Lc = 3xH+90(m)
. HÕalã wÕÐthÕr anáhoring
Lá = 4xH + 145 (m)
₠) u.Ú. standard (Admira|ty Manua|of
Seamanship, London):
Lc=27.5x1.51Hor Ns = 1.SvTl
Lá: Iength of áabIe to be paid out (m)
½ : water depth (m)
Ns: shaákIes.of áab|e to be àaid out
Fig.3-2
LÕngth of áablÕ to bÕ paid out
(U.K & JapÐnese standÐrd)
A Guide to ship Ýandlins | Øs
E!fil!fl ln-Harbor Ship Handling
Anáhor and Anáhor CablÕ
ThÕ spÕáifiáations of anchor and anáhor áablÕ to bÕ ÕquippÕd arÕ dÕtÕrminÕd with thÕ µquipmÕnt Num-
bÕr of thÕ ship stipulatÕd in thÕ RÕgulations for µquipmÕnt of Ships.
µaáh álassifiáation soáiÕty lays down its own rÕquirÕmÕnts in áomplianáÕ rvith thÕ abovÕ standard.
Anáhor áapabi l i ty
It is dÕsirablÕ that an anáhor Õåhibits ovÕrall áapability áovÕring thÕ following propÕftiÕs:
1. The anÞhor f|ukes bite into the seabed without fai| after the anáhor is Iet go.
2. Âhe anáhor possesses suffiáient holding power (resistanáe) to áope with the foráe dragging the anáhor.
3. The anáhor maintains postura| stabi|ity without turning over when it is pu||ed through the seabed.
Types of anáhor
ThÕ major anáhors áommonly usÕd in mÕráhant ships and naval vÕssÕls arÕ shown in Fig.3-4.
In mÕráhant ships, the AC14 typÕ anáhor appÕars to bÕ thÕ most widÕly usÕd, bÕáause of its high holding powÕr
and postural stability.
Fig.3.4 MajÞr anáhors
Danforth
Hol di ng power of anáhor
ThÕ holding powÕr of thÕ anáhor is normallã ÕxprÕssÕd as a faátor of its own wÕight
ho|ding power of anáhor (ton)
weight of the anchor (ton)
áoeffiáient of the ho|ding power
Hp:
Wa:
l a:
Hp=l a'Wa or ^"=#
Jl s anáhor
AC14 Ðnchor
046 | A Gui de to Shi p HÐndIi ng
3..l Anáhoring
For examplÕ, thÕ AÁ14 anáhor will hold morr than 10 timÕs its own wÕight if thÕ sÕabÕd is good;
in poor sÕabÕd of sÞft, silty mud, thÕ holding powÕr will drop to about 3 times anáhÞr wÕight.
HowÕvÕæ thÕ holding pÞwÕr of thÕ JIS t1pÕ anáhor is, at bÕst, half that of anACl4 anáhor of Õqual
wÕight under normal seabÕd áonditions.
Fig.3-5 shows thÕ AC14 anáhor undÕr pulling tÕst.
ThÕ figurÕ shows that thÕ anáhor bitÕs wÕll into thÕ sÕabÕd and maintains stablÕ postuâÕ without tæm-
ing ovÕr.
on the other hand, Fig.3-6 indiáatÕs that thÕ »S anáhor tÕnds to turn ovÕr whÕn draggÕd, and subsÕ-
quÕntly brÕaks out with flukes up.
Fig.3.Ñ JIS anáhor turnÕd over
Fig.3-7 illustratÕs thÕ áharaátÕristiá hold.
ing power áæryÕs of thÕ ACl4 and JIS
anáhors. ThÕ AC14 anáhor Õxhibits high
Ðnd stablÕ holding power' whÕreas thÕ
holding power of thÕ JIS anáhor dÕálinÕs
drastiÞally aftÕr it turns ovÕr and losÕs
thÕ ability to grip thÕ srabÕd.
Ä
()
Ä
.ç
áÛ
Ä
())
E
o
â
Fig.3.5 AC14 anáhor biting into the bottom
Fig.3-7 Holding powÕr áharaátÕristiás áurvÕ
PulIing distanáe
A Gèido to ship Ýandling I o47
I
I
I
!ft[s@ In-HÐrbor Ship Handling
BÕsidÕs thÕ holding powÕr of thÕ anáhoÓ itsÕlf. thÕ áontÓibution Þf thÕ anáhor áablÕ áannot bÕ ignorÕd.
MÞrÕovÕæ thÕ anáhor áablÕ plays thÕ impoÓtant rolÕ Þf absorÌing somÕ of thÕ ÕnÕrgv aáting on thÕ an-
áhor by áhanging thÕ shapÕ of its áatÕnary.
Fig.3-8 shows thÕ anáhoring systÕm whÕn ridin-s to a sino1Õ anL.hLrr.
Total mooring powÕr P is thÕ sum of thÕ holding poÒ.ÕÓ of thÕ ÐnáhÞr r Hp = ,|3. !'|/" ) and thÕ friátional
rÕsi stanáÕ of thÕ áabl Õ l ai d ovÕrthÕ sÕabÕd (l".W".1 ): thÐt i s.
t:::l
t I-.'|nl r|i nßnarl '.l, Áïtananrna¡
Ó- l |VIUI|tl l Pa| r_-vel µl Iá|)r Àá1r[+
P= l".WÐ+Ic.Wc.l/
Fi g3-8 -
P : mooring power (ho|ding pîr,ier of anáhor Ðnd áab|e) (ton)
^a: áoeffi ái ent of hol di ng power
Wa: anÞhor wei ght (ton)
l á: áoeffi ái ent of áÐb|e resi staÛáe 9gr æßi t l ength (}á=0.75)
Wá: áÐb|e Wei ght per Uni t l engÓth i ton ä]
f : ho|di ng |ength of áabl Õ (mi
SeÐbed
×.1
AnáhÞring opÕratiÞns
Approaáh to an anáhor berth
Anáhoring mÕthod variÕs aááording to watÕr dÕpth, áurâÕnt and wind áonditions at thÕ anáhoragÕ.
Riding to a singlÕ anáhor by dropping anáhor (lÕtting go thÕ anáhor undÕr stÕmway) is normally usÕd
bÕáausÕ of its handling simpliáity whÕn lÕtting go or wÕighing anáhor. ThÕ ship proáÕÕds in aááordanáÕ
with thÕ spÕÕd rÕduátion plan, and thÕ ÕnginÕ is stoppÕd bÕforÕ arÓiving at thÕ anáhor bÕrth, advanáing
solÕly by inÕr1ia. ThÕ ÕnginÕ is put astÕrn just bÕforÕ thÕ intÕndÕd loáation so that thÕ ship may áomÕ to
a stop in thÕ anáhor bÕrth. ThÕ anáhor is lÕt go and thÕ áablÕ is paid out undÕr stÕrnway.
PÕrsonnÕl on thÕ navigation bridgÕ rÕáord thÕ ship's hÕading whÕn thÕ anáhor is lÕt go, and plot thÕ
position ofthÕ bridgÕ (anáhor position) on thÕ áhar1.
Anáhori ng i n water of 20 meters or Iess depth
WhÕn anáhoring in watÕr of 20 mÕtÕrs or lÕss dÕpth' thÕ anáhor may bÕ lÕt go frÕÕly by rÕlÕasing thÕ
brakÕ from thÕ áoák-bill position, and an amount of áablÕ approximatÕly Õqual to twiáÕ thÕ dÕpth Þf
watÕr shÞuld first bÕ allowÕd to run out frÕÕly to ÕnablÕ thÕ anáhor to ÕmbÕd itsÕlf. ThÕrÕaftÕæ thÕ
windlass brakÕ should bÕ appliÕd so that thÕ áablÕ is kÕpt growing at an ang|e of about 30 dÕgâeÕs tÞ
thÕ vÕrtiáal. ThÕ brakÕ should not bÕ appliÕd foráÕfully. A frÕe-falling anáhoring áan áausÕ parting of
thÕ áablÕ and damagÕ to thÕ windlass.
In largÕ ships, stÕrnwaã after lÕtting go thÕ anáhor should bÕ adjustÕd within 0.5 to 1.0 knot to prÕvÕnt
an ÕxáÕssive strain on thÕ áablÕ. WhÕn thÕ intÕndÕd shaáklÕs of thÕ áablÕ arÕ Þaid out. suffiáiÕnt brakÕ
should bÕ appliÕd to áausÕ thÕ flukÕs ofthe anáhor bitr into thÕ sÕabÕd.
When thÕ áablÕ tautÕns and thÕn slaákÕns, it is a sign that thÕ ship is brought up. At thÕ samÕ timÕ, thÕ
ship bÕgins to turn towards thÕ wÕathÕr'
Anchoring in water of 20 to 50 meters depth
WhÕn anáhoring in watÕr of 20 to 50 mrtrrs
dÕpth, thÕ frÕÕ-fall anáhoring from thÕ áoák-bill
position may áausÕ thÕ áablÕ to attain a dangÕr-
ous spÕÕd as it runs out, thÕ rÕsult bÕing a parting
ofthÕ ÕntirÕ áablÕ.
ThÕrÕ is also risk that thÕ anáhor may fraáturÕ on
striking thÕ bottom at high spÕÕd.
Âo prevÕnt suáh hazards, walk baák thÕ anáhor
into thÕ watÕr until it rÕaáhÕs about 5 mÕters
abovÕ thÕ bottom, thÕn lÕt go thÕ anáhor.
AftÕrwards, thÕ propÕr brakÕ shÞuld bÕ appliÕd to
áontrol áablÕ ruèing out spÕÕd, and stÕmway of
thÕ ship should bÕ maintainÕd within thÕ pÕrmis-
siblÕ range. (Fig.3-9)
l u.
³-
Fig3-9
AnáhÞÓing in watÕr of 20 tÞ 50 rr.rÕtÕrs dÕpth
A Guide to ship ÝÐnd|ins i 049
!@s@ In-Harbor Ship Handling
Anáhori ng i n water of 50 meters or greater depth (Deep anáhori ng)
WhÕn anáhoring in watÕr of 50 mÕtÕrs or greatÕr depth' thÕ anÞhor and thÕ amount of áablÕ intÕndÕd
for usÕ arÕ paid out by thÕ walk-baák mÕthod'
In largÕ ships' stÕmway ovÕr thÕ ground should not ÕxáÕÕd 0.5 knot aftÕr thÕ anáhor has bÕÕn ÕmbÕd-
dÕd in thÕ bottom'
Âhis is bÕáausÕ if thÕ ship's stÕÓnway is gâÕatÕr than thÕ walk out speÕd of thÕ áable, parting the áable
or damagÕ to thÕ windlass may oááur duÕ to ÕxáÕssivÕ strain on thÕ áablÕ. (Fig.3-l0)
o.G. Speed (Stern way) < è¼
Fi g3-10 AnáhÞÓi ng tn rr'atÕÓ Þf 50 mÕtÕrs or grÕatÕr dÕpth (DÕÕà anáhÞÓi n.!])
Anáhor position
WhÕn anáhoring is áomplÕtÕd, thÕ prÕáisÕ anáhor position should bÕ plottÕd on thÕ áhart taking into
aááount thÕ distanáÕ from thÕ bow to thÕ navigation bridgÕ and thÕ amount ÞfáablÕ paid out.
Permjssi bl e water depth for anáhori ng
PÕrmissiblÕ watÕr dÕpth for anáhoring is not dÕtÕrminÕd by thÕ total lÕngth of ÕquippÕd áablÕ, but bã
thÕ áapaáity of thÕ windlass.
GÕnÕrally, a windlass has a lift áapaáity of 3 to 4 shaáklÕs with an anáhor. Aááordingly, pÕrmissiblÕ
watÕr dÕpth will bÕ in thÕ rangÕ bÕtwÕÕn 82 to 110 mÕtÕrs.
ÂhÕ ratÕd áapaáitã of a windlass must bÕ suffiáiÕnt to hoist two shaáklÕs of áablÕ at an avÕragÕ ratÕ of
9 mÕtÕrs/min, with thÕ anáhor and 3 shaáklÕs of áablÕ suspÕndÕd in watÕr without touáhing thÕ bottom.
(ÂhÕ rough áaláulation at this ratÕd capacitã is that 3 minutÕs is nÕÕdÕd to hoist onÕ shaáklÕ of áablÕ.)
050 | A Gui de to Shi p HÐndl i ng
I
3.1 Anáhoring
Anáhoring UndÕr Wind and CurrÕnt µffÕáts
In an anáhoragÕ whÕrÕ thÕ ÕffeÞts Þf wind andlor áurrÕnt aIÕ strong, thÕrÕ is risk of dragging anáhor
duÕ to ÕxáÕssivÕ strain on thÕ áablÕ.
ThÕrÕ also is risk of holding failurÕ of thÕ anáhoæ as thÕ áablÕ is oftÕn laid out mÕandÕringly along thÕ
bottom, whiáh hindÕrs thÕ anáhor's ability to ÕmbÕd and hold.
WhÕn approaáhing thÕ anáhÞragÕ, wÕll-áhosÕn landmarks, bÕam rÕfÕrÕnáÕs and thÕ ship's spÕÕd mÕtÕr
arÕ to bÕ usÕd to rÕákÞn thÕ ship's movÕmÕnt' as thÕ prÕáisÕ spÕÕd ovÕr thÕ grÞund is diffiáult to
áonfirm.
Approaching with head-to-wind/stream
WhÕn riding to a singlÕ anáhoæ thÕ approaáh is madÕ head-tÞ-wind or hÕad-to-strÕam, and then the anáhor is
lÕt go.
To allow thÕ anáhor to ÕmbÕd and hold, a lÕngth of áablÕ morÕ than twiáÕ thÕ dÕàth of thÕ watÕr should bÕ al-
lowÕd at first to run out freely, aftÕr whiáh a suffiáiÕnt lÕngth of áablÕ should bÕ paid out rrndÕr brakr to prÕvÕnt
thÕ anÞhor from bÕing draggÕd.
Approaching with wind or áurrent on the beam
WhÕn approaáhing rvith wind or áurrÕnt on thÕ bÕam, suffiáiÕnt spÕÕd is rÕquiâÕd to maintain thÕ vÕssÕl's
prÕdÕtÕrminÕd traák bÕáausÕ lÕÕway or áurrÕnt sÕt inárÕasÕs drastiáally as thÕ ship's SprÕd drárrasÕs.
ThÕ ship should stÕm thÕ wind or ÞurrÕnt just bÕforÕ lÕtting go thÕ anáhoæ at whiáh timÕ preparation
for making bold altÕration ofáoursÕ is nÕáÕssary sináÕ thÕ vÕssrl rapidly losÕs way.
ThÕ wÕathÕr anáhor should be lÕt go with thÕ ship stoppÕd, and as thÕ ship drifts downstrÕam thÕ áablÕ
should bÕ paid out gradually (if nÕáÕssary thÕ astÕrn ÕnginÕ may bÕ usÕd) in suáh a way as to kÕÕp the
ship hÕad-to-wind or hÕad-to-strÕam.
Approaching with wind or áurrent on the stern
Anáhoring with wind or áurrÕnt on thÕ stÕrn should bÕ avoidÕd bÕáausÕ áontrÞl Þf hÕadway is difftáult
and thÕ áablÕ may bÕ subjÕátÕd to an ÕxárssivÕ strain.
If thÕrÕ is no othÕr altÕrnativÕ' thÕn mÐkÕ thÕ approaáh with hÕadway as slow as possible, and lÕt go thÕ
turning sidÕ anáhÞrjust bÕforÕ thÕ loáation ofthÕ anáhoragÕ.
A Guide to ship ÝÐndling 05.|
!ft!@@ In-Hartlor Shià Handling
Swing MotiÞns and Dragging Anáhor
A ship at anáhor will swing around thÕ anáhorÕd position in thÕ wind, dâawing a figurÕ-Õight, as shown
i n Fi g.3-11.
SubsÕquÕnt tÞ hÕad-to-wind position at thÕ ÕåtrÕmÕ Õnd of thÕ
windward (Fig3-lr o,o), thÕ ship bÕgins to bÕ swÕpt away
baákward. WhÕn thr ship's forÕ-and-aft linÕ is in line with
thÕ áablÕ dirÕátion or a littlÕ aftÕr (Fig.3-11o,@), maxi-
mum tÕnsion is ÕxÕrtÕd on thÕ áablÕ.
Dragging anáhor will oáÞur whÕn thÕ anchor losÕs its grip on
thÕ boffom and starts sliding ovÕr thÕ bottom, a rÕsult of im-
pulsÕ foráÕ ÕxáÕeding thÕ anáhor's holding powÕr.
To áontrol swing motion, the following measures are taken:
1. Deepen ship's draft by ba||asting to reduáe wind-affÕátÕd area
2. Adjust shi p's tri m by-the-head whi l e keepi ng the propel l er
under water
3. Use a swi ng-áheák anáhor wi th another anáhor, |owÕri ng i t
to one-and-half deoths of Water on its áable
For PÁÁs or LNG áarâiÕrs with largÕ wind-affÕátÕd arÕas,
risk of dâagging anáhor is said to bÕ high at thÕ following
wind spÕÕds:
15 m/s whÕn lying at a singlÕ anáhor, 20 rn|s whÕn a swing-
áhÕák anáhor is droppÕd, and 25 m,/s ÕvÕn whÕn thÕ ship is
lying at two anÞhors.
Anáhor Watáh
Fig.3-11 Swing motion in wind
PÕrsonnÕl on anáhor watáh shÞuld pay striát attÕntion to suddÕn áhanges ofwÕathÕæ signs ofdragging
anáhoæ signs of áablÕ fouling and dangÕrous bÕhaviÞr of othÕr ships in thÕ viáinity, and thÕ mastrr
should immÕdiatÕly bÕ irrformÕd whÕn anything unusual is obsÕrvÕd.
WhÕn thÕ mastÕr dÕtÕáts signs of dragging anÞhoæ thÕ following ÞountÕr mrasurÕs arÕ takÕn (dÕpÕnd-
ing on thÕ situation):
. Letti ng go the swi ng-áheák anáhor
. Paying out an extra length of the áable
. Keepi ng the shi p's hÕad to the wi nd and easi ng áabIe tensi on usi ng the mai n engi ne and ruddÕr, or bow
thruster.
Wi nd
+
052 A Gui de to Shi p Handl i ng
3.1 Anáhoring
othÕr mÕasèÕs' suáh as shifting anáhoragÕ or drifting offshore also should bÕ áonsidÕred.
MÕthods of dÕtÕáting anáhor dragging arÕ as follows:
. Checking the ship,s position by rÐdar or other instruments
. Checking the áourse reáorder
Þ Cheáki ng the shi p's swi ng behavi or
. Cheáking tightening sequenáes of the áab|e
. Cheáki ng the i ndi áator of the Dopp|er |og
ThÕ following phÕnomÕna áan bÕ rÕgardÕd as Õarly signs of thÕ anáhor bÕing draggÕd:
. the áourse reáorder indiáates a distorted áurve
i nstead of a regu|ar si ne áurve
. the periodical swing motion of the hull is stopped,
and the shi p i s gradual l y swept down wi th wi nd
on one si de of the hul l (Fi g.3-12)
o the Dopp|er log indiáates the ship is moving in a
áertain direátion at a rate of one knot or more
over the ground
Þ the cabl e remai ns taut at a|l ti mes
. abnormal vibration is felt on the hull
. the re|ati ve posi ti ons of other shi ps i n the vi ái ni ty
áhange markedly
As statÕd abovÕ, thÕ most important thing is Õarly
dÕtÕátion of dragging anáhor whÕn lying at Ðnáhor
in a salÕ.
ârajeátory of anÞhor
Ârajeátory of the ship.s
áenter of gravity
í
.Û
.Ä .'.al
áäD
Ù6
-e'
Ä;
¾
Wind
+
Fig.3.12 DraggingÐnáhor
A Guido to shiP Ýandlins / 053
l r
!ftfisfi! In-Harbor Ship Handling
Sighting anáhor
In a rivÕr or an Õstuary thÕ boffom is usually áovrrÕd with a thiák layÕr of silt or soft mud, and somÕ-
timÕs it may bÕ diffiáult to wÕigh anáhor aftÕr it has bÕÕn buriÕd dÕÕp in mud for an ÕxtÕndÕd pÕriod.
WhÕn a ship is obligÕd to |aã at anáhor in suáh an anáhoragÕ for a long pÕriÞd, thÕ anáhor should bÕ
hovÕ up and lÕt go again evÕryday or áouplÕ of days to prrvÕnt it frÞm gÕtting stuák'
Sl i ppi ng anÞhor
In an ÕmÕrgÕnáy, thÕ ship may bÕ obligÕd to slip the áablÕ or áablÕs and proáeÕd to sÕa.
WhÕn slipping a áablÕ, thÕ Õnd should bÕ buoyÕd to ÕnablÕ it and thÕ anáhor to bÕ rÕÞovÕrÕd, and thÕ
wirÕ ropÕ buoy pÕndant usÕd should be of suffiáiÕnt strÕngth to rÕáovÕr thÕ áablÕ.
\¼Õighing Anáhor
PrÕparations for wÕighing anáhor ÐrÕ thÕ samÕ proáÕdurÕs for anáhoring.
. Preparation of pumping is required for washing the anáhor and áable.
Þ Heaving in the áab|e is áommenáed by the master's order.
. When the áable is taut due to wind and áurrent, or when an exáessive strain is exerted on the áab|e,
mai n engi ne or bow thruster i s used to ease tensi on on the áabIe.
Þ Âhe brake is applied when the anáhor is fina||y hove up into the hawse pipe, and the áable ho|der is
disengaged. Âhe stopper is set after áonfirming it is no longer bearing the anáhor.s load.
Þ After the foreáast|e-station is dismissed, anáhor |ashings shouId be seáured firmly as these are very
important in preventing the anáhor and áable from running out to the bitter end in stormy seas.
054 I A Gæide to Ship HÐndling
3.1 Anáhoring 3.2 BÕtthing
-l
.....:::
GÕnÕral
In haâbors and ports whÕrÕ manÕuvÕÓing arÕas arÕ áonfinÕd and shalloé thÕrÕ arÕ many navigational
rÕstriáiions. ThÕrÕforÕ' ship opÕÓators arÕ rÕquirÕd to manÕuvÕr thÕir vÕssÕls in aááordanáÕ with prÕ-
vailing ÕnvironmÕntal áÞnditions. Additionally' whÕn ÕntÕring and lÕaving port also involvÕs bÕrthing
and unbÕrthing opÕrations, ship handling is not Õasy. This diftiáulty is duÕ to thÕ problÕm of dirÕátional
áontrol and áouâsÕ-kÕÕping, a diâÕát âesult ofpoor stÕÕrability at low spÕÕd and thÕ influrnáe ofwind
and áurrÕnt. UndÕâ suáh áiâáumstÐnáÕs' ship ÞpÕrators aro rÕquirÕd to usÕ assistanáÕ in ship handling,
assistanáÕ suáh as thÕ usÕ Þf tugs whÕn nÕáÕssary in áonjunátion with thÕir own full undÕrstanding of
ship manÕuvÕrability, ináluding usÕ of ruddÕr dÕflÕátion to áhÕák Ãaw at low spÕÕd, and thÕ stopping
powÕr of various rÕvÕrsÕ ÕnginÕ sÕttirrgs.
AssistanáÕ by Tugs
1. Types of tug
Tugs arÕ álassifiÕd by propulsion typÕ aS follows:
Þ Voith-Sáhneider Propel|er (VSP type)
o Contro|Iabl e Pi táh Prope||er (CPP type)
. Azi muthi ng Dri ve Propel l er (Z type)
In Japan, thÕ Azimuthing DrivÕ PâopÕllÕr Tãpe (Z typÕ) is thÕ prÕdominant tug.
Suáh tugs arÕ ÕquippÕd with two stÕÕrablÕ propulsion units that rÕvolvÕ 360 dÕgrÕÕs.
By áontrolling both thÕ dirÕátion and rÕvolutions ofthÕ propÕllÕrs, tug assistanáÕ for ship handling is
availablÕ in all dirÕátions and with varying thrust'
A Gæide to Ship HÐndlin" l *i
Fig.3.13 VSP tãpÕ propulsiÞn
Fig.3-14 CPÀ type pâÞpulsion
Fig.3-15 Z type propulsion
!ftfi@fi! rn-Harbor Ship Handting
2. Âowing force of a tug
WhÕn a fug is built, its towing foráÕ is mÕasurÕd
by a pulling tÕst as shown in Fig.3-16, whÕrÕ thÕ
fug's strÕngth of pull on thÕ bollard is dÕtÕrminÕd.
ThÕ valuÕ for bollard pull (towing foráÕ) variÕs
with thÕ typÕ of main ÕnginÕ and propulsion sys-
tÕm. ThÕ bollard pull of a Z tãpe tug is said to bÕ
approåimatÕly 1.5 tons ahÕad and 1.4 tons astÕm
pÕr 100 BHP of thÕ tug.
ThÕ bollard pull of a VSP t1pÕ tug is said to ÌÕ
approåimatÕly l.0 ton ahÕad and 0.7 ton astÕrn
pÕr l00 BHP of thÕ fug.
Fig.3-1Ñ MÕasurÕmÕnt Þf towing foráe (boliard pull)
HowÕvÕæ thÕ towing foráÕ of a tug will dÕárÕasÕ whÕn: 50
o the shi p bei ng assi sted i s maki ng headway
othe tug,s di sáharge áurrent i mpaáts agai nst
the shi p's underwater hul l
.the tug and the shi à are bei ng osái l l ated by
seas and swells
| 2000 3000
BHP of tug 1Òs;
Fig.3.17 BollaÓd pull vÕrsus BHP of tugs
Partiáularly, whÕn thÕ ship assistÕd is making hÕadway, thÕ inárÕasÕ in thr tug,s powÕr áonsumption
for latÕral motion mÕans that effÕátivÕ towing foráÕ is rÕduáed sharply as ship spÕÕd inárÕasÕs (SÕÕ
Fig.3-r8). As thÕ ship gains hÕadway and its spÕÕd inárÕasÕS, it will inárÕasingly drag thÕ tug, rvÕn
to thÕ point whÕrÕ thÕ tug, bÕáausÕ of its posturÕ, is in dangÕr of hÕÕling ovÕr.
á
í
_×0
o-
P20
Ä
Eto
LÆ
8 roo
aBo
E
(' °n
Ñ
-o
±40
á
Ä .,n
-
U'
Ä
Eo
Ä
2·4
Shi p speed 1Únot1
Towing ³oráÕ rÕduátion with a ship *".,'"*Çfl;3;11
(onÕ-knÞt hÕadwaã = l00)
Âugboat
056 l A Guide to Ship HÐndling
I
I
3. Use of tugs
ThÕ usÕ oftugs is dÕáidÕd in aááordanáÕ with ship han-
dling rÕquirÕmÕnts, suáh as áontrolling a towÕd ship's
spÕÕd, latÕral motion and yaw-ratÕ.
(1) Latera| moti on áontro|
In pulling-out opÕrations, thÕ tug's paid-out ropÕ lÕngth
is rÕákonÕd ranging from 2.0 to 2.5 timÕs thÕ fug's
lÕngth (L). (Fig.3-19)
As thÕ towÕd ship's sizÕ inárÕasÕs, thÕ lÕngth of ropÕ
inÞrÕasÕs.
Fig.3.19 StandaÓd length Þf towin.t 1inÕ
Fig.3-20 shows thÕ alÂangÕmrnt for assistanáÕ in latÕral motion áontrol by onÕ tug.
It is áommon to usÕ this arrangÕmÕnt in áombination with a bow thrustÕr or with an anáhor.
Fig.3-21 shows thÕ arrangÕmrnt for assistanáÕ in latÕral motion áontrol by two tugs.
Â] =*n
I l s t I
*LJ *J
Ä
=
Fig.3.20 AssistarráÕ in latáÓÐl rnáltion
áontÓol b1 árrlÕ tug
(2) Pi voti ng moti on áontro|
Fig.3-22 shows thÕ aèangÕmÕnt for assistanáÕ in
pivoting motion áontrol.
RÕgarding tug opÕrations, ÕithÕr thÕ pushing or
pulling mÕthod is usÕd.
ThÕ pulling mÕthod is nÕÕdÕd for broad SÕa room;
this mÕthod suffÕrs from a dÕárÕasÕ in towing
foráÕ duÕ to thÕ impaát of disáhargÕ áuèÕnt' but
allows flÕxiblÕ usÕ of tus.
Fig.3-21 AssistanáÕ in latÕÓal motiÞrr
áontl-ol bã two tugs
LJ
Fig.3.22 AssistanáÕ in pivoting mÞtion áÞntrol bã onÕ tlÓ two tugs
A Guide to ship ÝÐndIing l 057
Elfi@@ In-HarbÞr Ship Handling
WhÕn a tug tows or pushÕs thÕ stÕrn of a ship, thÕ ship's pivot point wi1l bÕ aft Þ³ thÕ borr.. aboæt onÕ-
third thÕ ship lÕngth. (Fig.3-23, Fig.3-24) WhÕn thÕ bÞw is towÕd or pushÕd, thÕ pir'Þt point lr ill bÕ for.
ward of thÕ stÕrn about onÕ-thiÓd thÕ ship lÕngth.
Pivot point
Fi g.3-23
PÞi nt Þl.aátj Þl l Þ1.tt-t'g l l ná] ài\ Ot ]]tr]l l t .)i 'hi n
As thÕ poi nt of aáti on C ÕxÕrtÕd bã thÕ
tug shifts álosÕr to thÕ ship's áÕntÕr of
gravity G, thÕ pivot point P will shift
farthÕr from thÕ ÞÕntÕr of sâavitã G.
(Fig.3-2s)
ÁonsÕquÕntly, tuming in a short round
rÕquirÕs a áiráular manÕuvÕring arÕa with
a radius grÕatÕr than GP + |/2L, with thÕ
furning árntÕr at thÕ pivot point P.
As shown in Fig.3-26, thÕ farthÕr thÕ
point of aátion from thÕ áÕntÕr of gravi.
ty, thÕ smallÕr thÕ turning radius.
G
Fig.3-25
ÁhÐngÕ Þ³ àl r'l l t 1l ql j 111 .,' ;:h áh;tngÕ l n àÞrrl t Þf aáti Þrr
Fig.3-24
Ship rrndÕr pir'otirig rnáåiÞn
Fig.3-26
Óadius ê'ith áhan.qÕ in àoint of aátiÞn
P: Pivot point
G: Center of gravity
C: Point of aátiÞn
058 | A Gui de to Shi p HÐnd|i ng
Átlmparison of turning
Fig.3-27 shows thÕ trajÕátoriÕs of a ship undÕr onÕ-knot hÕadway making a 90-dÕgâÕÕ tum with thÕ as.
sistanáÕ of a fug pushing abÕam ÕithÕr thÕ bow or thÕ stÕrn Þf thÕ ship.
As shown in thÕ figurÕ, it is known that pushing abÕam of thÕ ship áausrs a rÕlativÕly largÕ kiÞk-out.
At thÕ samÕ timÕ' howÕvÕæ it ÕnablÕs thÕ ship to fum in a smaller manÕuvÕring arca thanif the ship
wÕrÕ pushÕd abÕam thÕ bow.
%rE Fis.3-27
CÞmparison Þf 90-dÕgrÕÕ tumiÛg trajÕátÞries when bÞw o' Ü"- ì.Øg-puÙo
WhÕn a fug assists thÕ pivÞting of a ship in áonditions of strong wind and áurrrnt, towing thÕ bow in
thÕ dirÕátion of thÕ wind Ðnd áurrÕnt rÕquirÕs a broad manÕuvÕring arÕa duÕ to the ship's inárÕasÕd
rangÕ of mÞtion. on thÕ othÕr hand, towing thÕ stÕrn against thÕ wind and áurrÕnt is ÕffÕátivÕ for pivot-
ing in a smallÕr arÕa. ThÕ ship will be in motion álosÕ to turning in a short round. (Fig.3-28)
Fis-}2S
l ug asslstanáÕ in pivÞtjng motion undÕÓ wißd Ðrl árèfl
ThÕrÕforÕ, álosÕ affÕntion should bÕ paid to ship hÐndling in mÐneuvÕring areas with stÓong wiods and
árÓrrnts.
Ar-*L-t i GD
!ft!@@ In-Harbor Shià Handling
(3) Requi rÕd towi ng foráe i n berthi ng operati ons
Fig.3-29 shows thÕ rÕquirÕd towing foráÕ on
bÕrthing opÕration rÕlativÕ to ship stze, para-
mÕtrizing water dÕpth (H) to draft (d) ratios,
(}Vd). In thÕ figurÕ, thÕ rÕquirÕd towing foráÕ
is shown vÕrtiáally, and vÕssÕl displaáÕmÕnt
tonnagÕ horizontally'
It should bÕ notÕd that thÕ rÕquirÕd towing
foráÕ inárÕasÕs as displaáÕmÕnt tonnagr grows
largÕr and watÕr dÕpth to draft ratio (H/d) bÕ-
áomÕs smallÕr.
---)- lÝloÞ.0
ThÕ numbÕr of tugs and thÕ
áonditions:
Þ áondi ti on of the berth
. shi p si ze
o shi p handl i ng method
o Weather áondi ti ons
o most i mportant|y, Wi nd ve|oái ty and áurrent set, as
wÕ|I as water depth to shi p's drÐft rati o (H/d).
In somÕ harbÞr arÕas, thÕ áritÕria for using tugs arr
laid down as shown in TabIÕ 3-1.
240
D.W. ton (uni t l o,ooo tons)
Fig.3-29
RÕquirÕd tug towing fÞráÕ whÕn bÕrthing
150Â+.200T->-1..,,,..
-__ñ-
ll/d 1.5 -__ñ-
powÕt nráÕSsary for bÕrthing opÕrations arÕ dÕpÕndÕnt on thÕ following
Âokyo Bay Pilot AssoáiÐtion (for referenáe)
â 200
9
a 160
o 1)n
())
.á 80
=
µ40
Bæ|ker
vLáá
':,:3
060 | A Guide to ship Ýandling
TablÕ 3.1 NumbÕr of tugs rÕquirÕd whÕn entÕring Þr lÕÐving
3.2 BÕrthing
(a) Safe handling of towropes
Slipping off or parting of towropÕs will rÕsult in sÕrious aááidÕnts.
In somÕ áasÕs, ship bitts to whiáh towropes arÕ madÕ fast laák suffiÞient strÕngth; it is nÕáÕssary to áhÕák thÕ
safe working load of bitts.
To prÕvÕnt damagÕ to a towâope, it shÞuld bÕ madÕ fast to thÕ innÕr bitts as far as áonditiÞns pÕrmit, as
shown in Fig.3-31.
SãnthÕtiá fibÕr ropÕ has high rÕsistanáÕ to áhafing over flat surfaáÕs, but poor rÕsistanáÕ against sharp ÕdgÕs
and sidÕslips.
DuÕ to malfunátions and rusty, rough surfaÞÕs of rollÕrs and fairlÕads, Þhafing áan áausÕ ropes to part.
For this rÕason, it is ÕssÕntial to maintain ship-mooring ÕquipmÕnt in good áondition.
For ÕxamplÕ, thÕ rusty surfaáÕs of fairlÕads must bÕ sárapÕd and smoothÕd, shafts must be rÕ-adjustÕd, and
rollÕrs gâÕasÕd.
If ropÕs arÕ bÕnt or strÕtáhÕd ovÕr sharp angles or áomlrs' or if thÕy ÞomÕ into áontaát with thÕ ship's hand-
rails, áhafing against sharp ÕdgÕs or áorners may áausÕ thr ropÕ to part' as shown in Fig.3-32.
Fig.3.31 Taking tow ropÕ to bitts
Fig.3.32 RopÕ in áontaát with sharp edge
For opÕrational safÕty, a hÕaving linÕ should bÕ usÕd with thÕ áolTÕát äpÕ Þf monkey fist.
NÕvÕr substitutÕ a shaáklÕ for a moÙÕy fist.
It is an unfortunatÕ faát that towropÕs or mooring lines in use will somÕtimes part for unforesÕÕn
reasons.
PartÕd linÕs áan Õasily áausÕ injuriÕs and fatalitiÕs.
ÂhÕrÕforÕ, kÕÕp pÕrsonnÕl from working or standing by on thÕ rxtÕnsion linÕs oftÕnsiÞnÕd ropÕs.
A Guide to shià Ýandling | 061
!ft@f, ln-Harbor ship Handling
BÕrthing and MÞoring
Berthing alongside a whÐrf
1. Speed of approach
In thÕ handling ofbÕrthing ships, it is vÕry important to áontrol the ship's approaÞh spÕÕd, as well as dirÕátional
áontrol. As a ship approaáhÕs its objeátive loáation, its hÕadway should gradually bÕ rÕduáÕd, and hull inertia
should bÕ stoppÕd at thÕ predÕtÕrmined point. on the assumption that thÕ ship áan Õmploy brÕaking powÕr
through thÕ usÕ of DÕad Slow AstÕrn enginÕ, guidelinÕs for spÕÕd reduátion sÞhemes for LNG áarriÕrs, PCCs
and áontainÕr ships arÕ shown in Fig.3-33. ThÕ samÕ guidÕlinÕs for VLCCs arÕ also shown in Fig.3-34.
10
10
8
|Û
í6
â'
3æ
Ä
2
8
Ä
E6
Þ
Eæ
a
)
0 500 1000 rs00 2000 2500 3000 0
Distanáe (m)
Fig.3.33 Speed rÕduátion sáhÕmÕs for LNGs, PÁCs,
and ContainÕr ships
1 500 ×000 4500 6000 7500 9000
Distanáe (m)
Fig.3-34 SpÕÕd rÕduátion sáhÕmÕs for VLCÁs
2. Approaáhing a wharf
To prÕvÕnt damage to thÕ wharf and fendÕrs, a|arge-size ship should rÕduáÕ its headway to zero somÕwhÕrÕ at
a distanÞÕ of onÕ ship lÕngth or ship brÕadth from the wharf, and then move |ateral|ã, bÕrthing with thÕ ship's
hÕading kÕpt parallÕl to thÕ wharf. Wharfs and shore-basÕd moor-
ing fÐáilitiÕs arÕ usually dÕsignÕd assuming a berthing vÕloáity of ·0o
15 ám/sÕá. Aátual bÕrthing vÕloáitiÕs arÕ muáh lowÕæ howÕvÕ., µ
and should not ÕåáÕÕd 10 ám/sÕá for ordinary-sizÕ shiàs, and 5 $ zoo
ám/sÕá for largÕ-sizÕ ships. FÕndÕrs absorb the berthing ÕnÕrgy of ¡
the ship. ThÕir purpose is to prevent damagÕ to hull and wharf. -? loo
WhÕn berthing with a ship,s heading nearly parallÕl to thÕ wharf, ₠
thÕ ÕnÕrgy of thÕ ship against thÕ mooring faáilitiÕs will inárÕase m
in proportion to displaáemÕnt tonnage and thÕ squarÕ of thÕ ship's 0
approaÞh vÕloáity, whiáh áaÛ be wâitten as:
Fig.3.35 BÕrthing ÕnÕIgy VÕrsus bÕrthing vÕloáity
ThÕ valuÕ of áoÕffiáiÕnt Á áhanges áonsiderably with thÕ typÕ of
ship, watÕr dÕpth and othÕr faátors. Fig.3-35 shows thÕ áaláula-
tÕd rÕsults of bÕrthing enÕrgy on raáh ship type, whÕrÕ it is
known that thÕ bÕrthing ÕnÕrgy of a VLÁÁ inárÕasÕs sharply
whÕn thÕ bÕrthing vÕloáity exáÕÕds 6 ám/sÕá.
µ=+.A. u,..
µ : Berthing energy (ton . m)
W: Disp|aáement tonnage (ton)
V : Òerthing ve|oáity (m/seá)
g : 9'8m/seá, C: Coeffiáient
Berthing speed < 8-10Þm/seÞ (genera|Iy)
4 6 S i a'12
062 | A Guid6 to ship ÝÐnd|ing
3.2 BÕrthi ng
3. Posi ti oni ng of shi p on berthi ng operati ons
WhÕn a PCC with a short parallÕl body is bÕrthing as shown in Fig.3-36, thÕ ship's bÞw or stÕrn has oááaslon-
ally áomÕ in áontaát with áomÕrs of thÕ wharf, áar-stopprls or bitts.
TËs áontaát is duÕ to a dirÕátional diffÕrÕnáÕ bÕtwÕÕn forÕ-and-aft linÕ of thÕ ship and thÕ faáÕ linÕ of thÕ wharf.
ThÕ rangÕ of áritiáal positioning, wherÕin a par1 of thÕ hull is not in áontaát with thÕ wharf, is dÕtÕrminÕd by
thÕ wharf faáÕ line and thÕ angular dÕviation Þf thÕ ship's hÕading fiom that wharfllinÕ. (Fig.3-37 right)
ThÕ lÕft sidÕ of Fig.3-37 shows thÕ
pÕrmissiblÕ amount of ovÕrhang R
vÕrsus thÕ angular dÕviation from thÕ
wharf linÕ (t on a PÁC.
From thÕ figurÕ' thÕ áritiáal angular
dÕviation áoßÕsponding to thÕ amount
of ovÕrhang áan bÕ found.
In thÕ plottÕd áasÕ, whÕn thÕ pÕrmissi-
blÕ amount of ovÕrhang is 3 mÕtÕrs,
thÕ áritiáal angular dÕviation of thÕ
stÕrn is 2.3 desrÕes.
Fender
Water level
Fig.3-36
CÓi ti áal àosi ti oni ng o1.a PÁÁ
Overhang (R)
i--j
i l
Â*l
ti
Hul l
1234
Angul ar devi ati on, a"
Fig.3-37
vÕl.sus aß]oullt of ovÕÓhang
PÕÓl ni ssi bIe l ngtl l Ðr dÕr i l ti Þn
A Guide to ship ÝÐnd,ins l 063
I
ffi!fi l l r-fl at UUt Jl l l P ßarræl Il tÚ
Moori ng
'1 . Mooring arrangement
MoÞring linÕs áontrol a ship's motion and makÕ thÕ ship fast to Ð fixÕd position.
Fig.3-38 shows a fundamental mooring arrangÕmÕnt. HÕadlinÕs and stÕrn linÕs arÕ usÕd to áontrÞl srrrgÕ' sway
andyaw. Spring linÕs áontrol drift.
MorÕovÕæ sináÕ it is dÕsirablÕ that Õaáh linÕ bÕ ÕxtÕndÕd as far as possible, it is nÕáÕssary that attÕntiÞn bÕ paid
during berthing operatiÞns to insurÕ thÕsÕ maximum lengths.
In a wharf whÕrÕ affangÕmÕnt of longÕr mooring linÕs is not possiblÕ, additional linÕs should bÕ dÕployÕd as
nÕáÕssary.
2. Moori ng foráe of moori ng |i nes
As shown in Fig.3-39' mooring foÓáÕ is thÕ horizontal áomponÕnt, T.áosd, of tÕnsion neÕdÕd to withstand thÕ
motion of a ship ÕxÕrtÕd by ÕxtÕmal foráÕs on thÕ hull. Aááordingly, as shown in Fig.3-40, thÕ horizontal
mooring foráÕ is rÕsolvÕd as follows:
.mooring foráÕ on thÕ forÕ-Ðnd-aft dirÕátion Tx:
.mooring foráÕ on thÕ transvÕrsÕ dirÕátion Ty:
Tx=T.cosd.áosc
Ây=T.áosd.si nä
, : angle of elevation of the mooring line
ä : horizontÐ| ang|e to the faáe Iine of wharf
Fig.3-39 DÕfinitiÞn of moÞring foráÕ
064 l A Gui de to shi à ÝÐnd|i ng
Fig.3.40 HoÓizontal moÞring foráÕ vÕátÞr
3.2 Berthing
ThÕ sum of Õaáh mooring foráÕ, on thÕ forÕ-aud-aft and transvrrse diâÕátion, is thr rÕsultÐnt mooring
foráÕ.
Critiáal mooring foráÕ to áope with all exteßral foráÕs is dÕtÕrminÕd by the Þondition that eaáh áompo-
nÕnt of exteßral foráÕ should not ÕxáeÕd thÕ áorrÕsponding áomponrnt of the sum of Õaáh mooring
foráÕ.
on thÕ other hand, áritiáal mooring foráÕ is dÕtÕrminÕd in rÕlation to thÕ strenä of mooring rÞpÕ or
thÕ brÕaking powÕr of thÕ mÞoÓing wináh.
That is, the load of Õaáh mooring line to withsØnd thÕ ÕåtÕrnal foráÕ on thÕ hull should always be
within thÕ range of thÕ safÕ working load of thÕ linÕ or brÕaking powÕr of Õaáh mooring wináh:
µxtÕÓnal foráÕ on hull < 60 % of ¼inimum Breaking Load (¼BL) of mooring linÕ
or
µxtÕrnÐl foráÕ on hullS BrÕaking powÕr of mooring wináh
The smallÕr value of eithÕÓ of the abovÕ opposing foráÕs bÕáomes the árifiáal mooring foráÕ.
Assuming a ship frÕÕ from ÕxtÕrnal forárs suáh Ðs wind and ár.rrrÕnt as moorÕd shown in Fig.3-38, a
áaláulated ÕåamplÕ Þf mooring foráÕ on thÕ transvÕrsÕ dirÕátion is shown in TablÕ 3-2.
The linÕ pull of wináhÕs is assumed to Ìe 25 tons, and all mooring lines, 14 linÕs in this áasÕ, arÕ
rqually pre-tÕnsionÕd.
The total mooring foráÕ on thÕ tÓavÕrsÕ dirÕátion is approximately 128 tons, and thÕ mooring foÓáÕ of
Õaáh line is within the range ofthÕ sÕttled line pull of thÕ mooring wináh.
TablÕ 3.2 CaláulatÕd example of number of mooring lines and mooring foÓáÕ on tansvÕÓse dirÕátion
A Guide to shiß Ýandlins | 065
!ft!@@ In.HarbÞr Ship HÐndling
3. shift of a ship under wind effeáts
WhÕn a wind of l0 m/s is blowing off thÕ wharf, thÕ amount of shift of a PÁC is simulatÕd undÕr vari
ous mooring áonditions:
(1) ThÕ ship has bÕÕn shiftÕd |atera|\ã l.6 mÕtÕrs undÕr thÕ moorins áondition shown in Fig.3.38 with Õaáh
moÞring linÕ of 70 mmä arrangÕd in pairs, 12 linÕs in total.
(2) WhÕn onÕ additional linÕ is dÕployÕd on Õaáh mooring point, ÕxáÕpt on thÕ tÊnr.ald and aft spring linÕs, thÕ
ship has bÕÕn shiftÕd latÕrally 1 .2 mÕtÕrs, thÕ rÕstraining ÕffÕát of thÕ additional liârÕs bÕing on1y 40 ám.
(3) WhÕn wirÕ ropÕs of 40 mm Ä arÕ madÕ fast to storm bitts as additiÞnal linÕs as shorr.n in Fig.3-41, thÕ ship
has bÕÕn shiftÕd latÕrally only 5 ám, and thÕ ÕffÕátivÕnÕss of storm bißs mooÓing is álÕarly dÕmonstratÕd.
In this áasÕ, Õaáh additional linÕ should bÕ as pÕrpÕndiáulaÓ as possiblÕ to IhÕ sltip's forÕ-and-aft linÕ, and
thÕ linÕs bÕ ÕxtÕndÕd as far as possiblÕ from thÕ edgÕ of thÕ wharf.
HowÕvÕr, whÕn wind vÕloáity ÕxáÕÕds l5 m/s, additional linÕs madÕ of sr.nthÕtiá matÕÓials will losÕ thÕir
rÕstraining powÕr, and thÕ ship will suffÕr a largÕ latÕral shift.
SomÕ TankÕr tÕrminals undÕr strong wind and/or áurârnt Õquip StoÓm wiIÕ and ß-ináh as shown :rÓ'µig3-42.
066 A Gui de to shi p Ýandl i ng
4. Moori ng l i nes
ThÕ numbÕrs' typÕs' lÕngths, diamÕtÕrs, and brÕaking loads of mooring linÕs with whiáh a ship should
bÕ ÕquippÕd arÕ stipulatÕd in thÕ µquipmÕnt NumbÕr.
Commonly, ships arÕ ÕquippÕd with morÕ mooring linÕs than thÕ µquipmÕnt NumbÕr rÕquirÕs.
SynthÕtiá fibÕr ropÕs arÕ madÕ of various matÕrials, suáh as nylon, polyÕstÕr and polypropylÕnÕ.
High pÕrformanáÕ fibÕr ropÕs arÕ now somÕtimÕs usÕd fÞr mooring linÕs. The fibÕr matÕrials usÕd in
thÕsÕ ropÕs arÕ muáh strongÕr and also stiffÕr than ÞonvÕntional ropÕ-making fibÕrs.
BÕáausÕ they arÕ muáh stiffÕr, ropÕs madÕ of this nÕrv álass of fibÕrs arÕ áallÕd high-mÞdulus fibÕr
ropÕs. ThÕsÕ high-modulus fibÕr ropÕs arÕ almost as strong as wirÕ ropÕs of thÕ samÕ sizÕ, and thÕã arÕ
also almÞst as stiff. WhilÕ thÕ propÕrtiÕs of sãnthÕtiá fibÕr ropÕ makÕ it highly rÕsistant to áhafing ovÕr
flat surfaáÕs, it has poor rÕsistanáÕ to áhafing ovÕr sharp ÕdgÕs and sidÕslips.
It also dÕtÕrioratÕs undÕr ÕxposurÕ to ultra-violÕt rays.
BÕáausÕ thÕ ÕxtÕnt of dÕtÕrioration in strÕngth of mooring linrs variÕs with áyálÕs and duration of usÕ,
it is nráÕssary to áhÕák thÕ áondition of mooring linÕs daily. WirÕ ropÕs (or high-modulus fibÕr ropÕs)
arÕ usÕd to moor tankÕrs and LNG áarriÕrs in ordÕr to avoid damage to loading arms; synthÕtiá fibÕr
ropos arr usÕd to moÞr ships of ÞthÕr äpÕs'
DÕploying additional linÕs for miåÕd mooring, thÕ áombination of full-lÕngth synthÕtiá ropÕs and wirÕs
should bÕ avoidÕd.
5. operational preáaution of mooring
Mixed mooring 1ß.ig×-a3)
Load of rope
47â
2â
1Â
1Â
2â
47â
Steel wire rope
Polypropylene rope
Nyl on rope
100Â µ@>
Fig.3-43 µffÕát Þf mÞoring matÕrial
A Gui de to shi p Ýaßdl i ng
3.2 Berthing
!ftfisfit In-Harbor Ship rrandling
Mixed mooring 1Óig×-aa)
LoÐd of rope
25Âl-100m
Load of short rope > Ioad of long rope
soTl-som
25â}-100m
ThÕrefore two or more lines lÕadins in the sÐmÕ dirÕátion
Fig.3-44
µffÕát of length of moorings
( sÐmÕ sizÕlsamÕ materials)
shorrld, as faÓ as pÞssible, Ì of the samÕ length.
Key numbers for mooring lines
11m:Línäh of tai| rope (Fig3-as)
60o/o:
18 months:
12 wires:
4-4-2=
MBL of ÂaiI rope + MÒL of Mooring wire}125o/o
(MBL meÐns MBL of eaáh material before making eyes and sp|iáes.)
MBL: ¼inimum Breaking Load
Brake áapaáity of Wináh + MBL of Mooring lines = 60%
Tail rope should be renewed every 18 months.
otherwise every tai| rope should be inspeáted and áertified by manufaáturer regularly'
RÐs ÂÐrrurÐh port regulations require more than 12 wire moodné for mooring at the sea berh.
4 head/stem lines-4 breast lines-2 spring Iines
125o/"=
Tail rope (Syßthetiá rope)
068 I A Guad6 to Ship Handlins
I
I
!g.*
ï-
L.#'t'
*:s.ê
GÕnÕraI
WhÕn navigating in sÕvÕrÕ following and quar1Õring SÕas. a stèp is lftÕh âÞ ÕnáountÕr various kinds of
dangÕrous phÕnomÕna, whiáh may lÕad to áapsizing. WÕ shÞuld. thÕrÕtÊrÕ. possÕSs thÕ fundamÕntal
skills for safÕ ship handling in following and quar1Õring SÕas tá) Ðr Þid suáh dÐngÕr.
With thÕ samÕ objÕátivÕ, thÕ I¼o has releasÕd GuidanáÕ to thÕ \I×stÕr ti-.r -\'oiding DangÕrous Sifua-
tions in Following and QuartÕring SÕas. In this sÕátion. lr Õ bÕsin r-".ith Ð basiá stèdy of vÕssÕl stabiliä
and thÕ fundamÕntal propÕrtiÕs of wavÕs, and thÕn mo\'Õ on ât-i .f,ÕsáÓibÕ àhÕnomÕna that posÕ a dangÕr
to ships and providÕ ÞpÕrational guidanÞÕ for dÕalin's rr ith thÕßr.
Stability of Ships
TrÐnsverse StÐbiIity
1) Righting momÕnt
A ship {loating at rÕst is in a statÕ of statiá ÕquiliÌÓium: that is. thÕ gâavitational foráÕs aáting on thÕ
áÕntÕr ofgravitã G, and thÕ buoyanáy aátin-s on thÕ áÕntÕÓ ofbuoyanáy B bÕing Õqual and aáting in
linÕ with onÕ anothÕr. ThÕ position of áÕntÕr of gâaliß. G rÓill remain fixÕd whÕn thÕ ship is hÕÕlÕd.
ThÕ áÕntÕr of buoyanáy B is thÕ gÕomÕtÓiá áÕntÕr of thÕ undÕrwatÕr part of thÕ ship in still watÕr.
WhÕn thÕ ship is hÕÕlrd by somÕ ÕxtÕrnai foráÕ. it æ-il1 mor-Õ to a position Bl in thÕ áÕntÕr of thÕ
submÕrgÕd volumÕ of thÕ ship. ThÕ foráÕs of rr.Õisht and buoyanáy arÕ Õaáh Õqual to thÕ ship's dis-
plaáÕmÕnt W, and aát vÕt1iáally in opposite dirÕátions' As shown in Fig.4-1, thÕ foráÕ of buoyanáy
aáting upwards through Bt whÕn thÕ ship is hÕÕlÕd u.ill produÞÕ a momÕnt tÕnding to right thÕ ship,
and this momÕnt is áaiáulatÕd by multiplyin.t thÕ displaáÕment W by thÕ righting lÕvÕr GZ, whiáh
is thÕ horizontal distanáÕ bÕtwÕÕn thÕ foráÕs ofÒ.Õight and buoyanáy.
070 ] A Gui de to Shi p HÐnd|i ng
i
4.1 Ship Handiing in Óo]Iotvii and QuartÕriræ SÕas
2) TransvÕrsÕ mrtaáentÕr and transvÕrsÕ metÐáÕntriá hÕight
In most ships, for small ang1Õs Þf hÕÕl of up to about l0 dÕgrÕÕs, thÕ linÕ of aátion of thÕ foráÕ of
buoyanáy Br will intÕrseát thÕ middiÕ linÕ of thÕ ship at a fixÕd point M (Fig.a-l)' ThÕ point M is
áallÕd thÕ transvrrsÕ mÕtaáÕntÕr' ÂhÕ span bÕtwÕÕn thÕ mÕtaáÕntÕr M and thÕ áÕntÕr of gravity G,
GM, is áallÕd thÕ mÕtaáÕntÓiá hÕight; it givÕs a mÕasurÕ of thÕ initial stability of thÕ ship, i.Õ. its sta-
bility at small anglÕs of hÕÕl. ÂhÕ gÓÕatÕr thÕ mÕtaáÕntriá hÕight, (i.Õ. thÕ lowÕr thÕ position of G),
thÕ grÕatÕr thÕ stabi1itã. In Fig.-l-l, thÕ anglÕ0 is Õqual to thÕ anglÕ of hÕÕl, and thÕ righting lÕvÕr
GZ is Õqual to G¼.sin0 {pror-idÕd that 0 is small and GM is positivÕ [G is bÕlow ¼]). If thÕ mÕt.
aáÕntriá hÕight is knorr.n. thÕ rrghtrng momÕnt áan bÕ found by multiplying thÕ righting lÕvÕr GZ by
thÕ ship's displaáÕmÕnt W:
Ri ghti ng moment =W 'GZ = W'GM .si n0
B:
M:
Center of buyanáy
Center of gravity
Metaáenter (Transverse)
ThÕ hÕight of thÕ transvÕrsÕ mÕtaáÕntÕr abovÕ thÕ áÕntÕr of buoyanáã S1.l is indiáatÕdby thÕ fol-
lowing fonnula:
i::..: -
B: breadth d: draft k: áoeffiáient
A ship with a largÕ transvÕrsÕ mÕtaáÕntriá hÕight will ro1l with a shotl' rapid motion; suáh a ship is
said to bÕ stiff. A ship with a small transvÕrsÕ mÕtaáentriá hÕight will ro1l with a long, slow motion;
suáh a ship is said to bÕ tÕndÕr.
TransvÕrsÕ stabiiity is a vÕry important faátor
whÕn it áomÕs to safÕ navigation in hÕavy
sÕas; wÕ rÕfÕr to it oftÕn in this áhaptÕr.
k#
Status
stiff
Âender
Transverse
lltetacenter
,, .:Largg
.. .9ìqrt . l
Rolling
,Rgpi{
..Sltiä..
ÂransvÕrsÕ mÕtaáenter and mÕtÐáÕntliá height
A Guide to ship ÝÐnd|ing l 071
!@fié Ship Handling inWavÕs
Longi tudi nal Stabi l i ty
ThÕ longitudinal mÕtaáÕntÕr Ml of a ship is
found in a mannÕr similar to that usÕd to find thÕ
transvÕrsÕ mÕtaáÕntÕr.
Fig.4-2 shows a ship tiàpÕd forward by somÕ Õx-
tÕrnal foráÕ; thÕ longifudinal áÕntÕr of buoyanáy
B has movÕd forward to Br. Thus a longitudinal
righting momÕnt W.Gz is produáÕd; whÕrÕ W is
thÕ displaáÕmÕnt of thÕ ship and GZ is thÕ lÕngth
Þf thÕ lÞngièdinal righting lÕvÕr. ThÕ longitudinal
mÕtaáÕntriá hÕight GMr- is givÕn vÕry roughly as
follows:
Fi g.J-2 Longi tudi nÐ| mÕtÐáÕntÕr
áenter of buoyanáy
Center of gravity
Metaáenter (Longrtuo]1a
GMI -- L L: ship length
It is sÕÕn that thÕ ship is far stiffÕr longitudinally than transvÕrsÕlr.. Âhis r..lÐtrÞnship wi1l bÕ usÕd whÕn
áonsidÕring thÕ nafural pitáhing pÕriod of a ship.
l l"._. ]"' ,
.l
o72 |^ Gui de to shi p ÝÐndl i ng
× {
4.l Shlp Hanálling in Following ar.rd QuaÓtÕÓing Seas
Siå FrÕÕdoms of MotiÞn in a SÕawav
ThÕ motions of a ship áan bÕ split into thrÕe mutually pÕlpÕndiáular translations of thÕ áÕntÕr of gravity
G and thrÕÕ rotations around G:
Three translations of the ship.s áenter of gravity G in the direátion of the X., Y- and Z-axes:
. surgÕ in thÕ longièdinal X-dirÕátion, positivÕ forward
. sway in thÕ lateral Y-dirÕátion, positivÕ to starboard sidÕ
. hÕavÕ in thÕ vÕrtiáal Z-dirÕátion' positivÕ downward
Âhree rotations about these Ðxes:
. roll about thÕ X-aåis, positivÕ right èming
. pitáh about thÕ Y-axis, positivÕ bow up motion
Þ yaw about thÕ Z-axis, positivÕ right tuming
ThÕsÕ dÕfinitions arÕ shown in Fig.4-3.
År
-:.. --''i
":'........-r--/*
Suéñ
Yr
XXt: Fore and after ro|ling aåis
Wl: Athwartships pitáhing axis
ZZt: Verlical yawing axis
.{i{;
Fig.4-3 Siå fiÕÕdÞn.rs Þ1.râÞtion
;
A Guide to ship Ýandling l 073
!ftfisf, Ship Handling inwaves
Basiá µlÕments of RÕgular WavÕs
l) DÕfining a harmoniá wavÕ
Fig.4-4 (a) and Fig.4-4 (b) dÕpiát harmoniá WavÕs' ( , from two diffÕrÕnt pÕrspÕáti\'Õs:
. Fig.4-4 (a) shows thÕ wavÕ profilÕ (with wavÕ amplitudÕ, o, and
wavÕ lÕngth' ,\ ) as a funátion of distanáÕ at a fixÕd instant in timÕ.
. Big,4-4 (b) shÞws timÕ rÕáord of thÕ wave profilÕ (with wavÕ ampli-
tudÕ, ₠l, and wavÕ frÕquenáy, ar) obsÕrvÕd at onÕ loáation.
H : Wave height
,l : Wavelength
Âw : Wave àriÞd
Cw : Wave propagation speed
(Phase veloáity)
a : Wave amplitude (H=24)
Crest : Highest point of wave
Troéh : Lowest àint of wave
( : ShÐàeofwave
Fig.4-4 (a)
H.:â :i.niá rr ar'Õ dÕfi nitions
Fis.a.4 Ä)
½;:ßl..niá rr.avÕ dÕfi nitions
From the abovÕ, basiá dÕfinitions of a harmoniá WavÕ áan be givÕn:
. A wavÕ's highÕst point is the árÕst and lowÕst surfaáe point is the trough
Þ 3 l WavÕ amplifudÕ (thÕ distanáÕ from thÕ still watÕr lÕvÕl to thÕ árÕst. or to thÕ trough)
. H : W.avÕ hÕight (H:2a; twiáÕ amplitudÕ)
Þ ,i. : Vy'avÕlength (horizontal distanáÕ bÕtwÕÕn any two suááÕssivÕ war'Õ árÕsts)
. Tw : WavÕ pÕriod (thÕ samÕ distanáÕ as wavÕlÕngth along thÕ timÕ axis ) ( sÕÕ Fig.4-4-b)
Þ Cw: WavÕ propagation spÕÕd or phasÕ vÕloáiä (,\ /Tw; vÕlÞáity at rvËáh thÕ wavÕ prÞfilÕ
undÕrgoes a áompletÕ 360.degrÕÕ áyálÕ or phasÕ ÞhangÕ)
. k : WavÕ numbÕr (k:2ßl I (rad./s))
. al : CiráularwavÕ frÕquÕnáy (áls:2ß¿w (rad./s))
. 0 : Vy'avÕ StrÕpnÕss (d :H/ ^ ; ratio of wavÕ hÕight to wavÕlÕngth. WhÕn wavÕs bÕáomÕ too high,
árÕsts break at thÕ uppÕr limit of H/ i. :1/l0.)
For phasÕ vÕloáity, Cw, it is important to undÕrstand that watÕr partiálÕs do not movÕ at this spÕÕd; onlã
the waveform movÕs with this phasÕ veloáity.
If thÕ rÜavÕfoßn movrs in thÕ positivÕ X dirÕátion' thÕ wavÕ profilÕ (thÕ shapÕ of thÕ watÕr srèfaáÕ) can
bÕ ÕxprÕssÕd as follows:
074 |^ Gui de to Shi p HÐndl i ng
l =a'cos(kx-art)
.:.:::
4.l Ship Handling in Following and QuartÕring SÕas
2) Basiá ÕlÕmÕnts of rÕgular dÕÕp wavÕs
By applying thÕ obtainÕd rÕlations to rÕgular dÕÕp wavÕs (longÕr dÕÕp-watÕr gâavity wavÕs)' simplÕ
and vÕry praátiáal rÕlations bÕtwÕÕn thÕ wavÕ-
lÕngth (m) and phasÕ vÕloáity (m/s), or wavÕ å::^".Y::::iY(á*) Cw=1.25±(ml91'.
pÕriod (s) áan bÕ ÕxprÕssÕd as follows: fr:1"j;:::ãl'-, Tw = 0.80»,l.(", ,:l.;.:'
....Çavelengl!l (t) l = 1.56.Tw2 (m}
¼isáÕllanÕous itÕms rÕlatÕd to wavÕs
1) Group vÕloáity and wavÕ Õnrrgy
WhÕn supÕrposing pÓopagating wavrs with slightly diffÕrÕnt wavÕlÕngths, gloup WavÕs
(thÕ ÕnvÕlÞpÕ of thÕ wavÕ paákÕt) arÕ árÕatÕd as shown in Fig.4-5.
1..*i:í..: :.:'..
Yry
' -/-,- \
, l'.
--------------->r
, Fig.4-5
Wave groups and grÞuà veloáitã
ThÕ ÕnvÕlopÕ ofthÕ wavÕ paákÕt propagatÕs at thÕ group vÕloáity, Ág. ThÕ group vÕloáity for dÕÕp wa-
tÕr Wavrs is ÕåprÕssÕd as: ág = } áw Cw: phase veloáity of the WÐve
ThÕ wÐvÕ enrrgy is also áonvÕyed along a gâoup vÕloáity (thÕ propagation ÞfswÕll).
:_:________- waÙ group -----------------------*
A Gui de to shi ß Ýand|i ní | 075
Elfisf, Ship Handting in WavÕs
2) Signifiáant wavÕ hÕight (HlÒ)
Signifiáant wavÕ height is dÕfinÕd as thÕ averagÕ
hÕight of thÕ highÕst ÞnÕ third (tz×) Þf all wavÕs rÕ.
áordÕd ovÕr a partiáular timÕ pÕriod. ThÕrÕ is a fair
áorrÕlation bÕtwÕÕn signifiáant wave hÕight and vis-
ually ÕstimatÕd wavÕ hÕight. Signifiáant wavÕ hÕight
is used as a gÕnÕral mÕasure ofsÕa roughnÕss.
Tp * 0.5\/t
L: ship length (m)
o Enáounter wave period (âÒ). As shown in Fig.4-1 , a ship making Vs (m/seá) is assumÕd to bÕ run-
ning obliquÕly in rÕgular wavÕs with thÕ ÕnáountÕr anglÕ of thÕ ship to wavÕs, a dÕgrÕÕs off thÕ
bow, wavÕs of truÕ pÕriod, Tw (:0.stÛ.), lÕngth, ,l, and phasÕ vÕloáity, Cw (: 1'25\³D.
As prÕviously mÕntionÕd, rnáountÕr wavÕ pÕriod is ÕxprÕssÕd as:
µnáountÕr wavÕ pÕriod: wavÕlÕngth,/rÕlativÕ vÕloáity to wavÕ
Ship spÕÕd pÕrpendiáular to thÕ wavÕ is ÕxprÕssÕd as Vs. áos a. ThÕrÕforÕ' thÕ ÕnáountÕr wavÕ pÕr-
iod is ÕxprÕssÕd by thÕ following Õquation:
+
Ship's speed (Vs)
TÒ=
Cw+Vs . áos 4
u'."-6^
,/ r-sz
oæ rÕfÕrring to thÕ prÕÙous rÕlationship,
TÒ=
1.25f1+vs .áos d
Fig.4.7 µnáountÕr wave àeriod (TÒ)
.Ñ
o
×
3) Natural rolling/pitáhing pÕriods and ÕnáountÕr wavÕ pÕriod "'*"',.;Æ.Â; Signifiáant wavÕ hÕight
. NaturaI roIIing period (TÒ)'
Natural rolling pÕriod is to bÕ mÕasurÕd whÕn thÕ ship is in áalm sÕas. ThÕ valuÕ is roughly Õsti-
matÕd by thÕ fÞllowing Õquation:
â± - 0.8Ò B: shià.s breadth
. .' _ 1GM GM: ship's metaáentriá height
¾ Natura| pitáhing period (Tß).
ThÕ valuÕ of natural piáhing pÕriod is roughly ÕstimatÕd by thÕ following Õquation:
076 A Gui de to shi à Ýand|i ng
4.1 Ship Handling in FÞllowing and QrrartÕring Seas
BasÕd on thÕ abovÕ Õquation, a diagâam is prÕparÕd as shown in Fig.4-8, and ÕnÞountÕr wavÕ pÕfl-
od (TÒ) is obtainÕd using thÕ ÕnáountÕr anglÕ of thr ship to wave (a), ship spÕed (Vs) and wavÕ
pÕriod (Tw).
A synáhronous rolling motion rr.i1l oááur whÕn thÕ rnáountÕr wavÕ pÕriÞd TÒ is nÕarly Õqual to thÕ
natural rolling pÕriod of thÕ
ship, TÚ, and this will áÐusÕ
largÕ rolling motions. Âhis phÕ-
nomÕnon will bÕ ÕxplainÕd in
thÕ subsÕquent sÕátion.
Ì(ampIe Vs: ]a KnÞì (stä+eed)
a : 3O"(ErîßïµrÐæb)
Tw: 1'l sÕá(Wweàriä
µ : 8 seá(µ'µo.µfurpebd)
2d
·40.
A=U rn'
36d ·;0"
90'
270'
24 22 20 18 16 14 12
µnáounter Deri od µ (s)
t70'
190'
Fig.4-8 DÕtÕrminÐtion Þf ÕnáountÕr wavÕ pÕriod (TÒ)
70"
2ä.
I 80-
\ 280'
-|1lÞo"
f7 260"
71ßo.
7 uo"
120
240'
6
210'
lî"
2ä
·2 30 28 26
A Gui de to shi p ÝÐndl i nn |o,,
!ftfiftf, ShipHandlinginWavÕs
DangÕrous µnáountÕr With lligh WavÕ GrÞup
ThÕ ÕnvÕlopÕ of wavÕ paákÕt propagatÕs at thÕ
group vÕloáitÃ, Ág, in dÕÕp wator;
Ág--|l2. Cw (SÕÕ pagÕ 075). WhÕn thÕ abovÕ wavÕ
group vÕloáity is nÕaä Õqual to thÕ spÕÕd áomponÕnt
of a ship to thÕ wind dirÕátion, dangÕrous ÕnáountÕr
with high wavÕ group oáárrrs; this is a phÕnomÕnon
whÕrÕby thÕ ship is attÐáked by a suááession of high
wavÕs. As mÕntionÕd abovÕ, thÕ maåimum wavÕ hÕight
of thÕ suááessivÕ wavÕs áan rÕaáh almost twiáÕ thÕ ob-
sÕrvÕd wavÕ hÕiä ofthÕ sÕa statÕ áonáÕrnÕd. This sit-
uation áÐn rÕsult in thÕ rÕduátion of synáhronous rolltng
motion, paramÕtriá rolling rnotion, or thÕ oááurrÕnáÕ of
sÕvÕral dangÕrous phÕnomÕna, heightÕning thÕ risk of
áapsizÕ.
Fi g.4-9 shows thÕ dÕfi ni ti on of ÕnáountÕr angl Õ
x'mrasured from thÕ stÕrn of a shi p.
Fig.4-10 shows a diagram indiáating thÕ dangÕrous zone for ÕnáountÕring a high wavÕ group; it is
usÕd to dÕtÕrminÕ dangÕrous áÞnditions. In thÕ figurÕ, Õaáh ratio of ship spÕÕd V (knots) to wavÕ pÕr-
iod T (s), V/T, is shown as a
áonáÕntriá áirálÕ, and rncoun-
tÕr anglÕ å aS a radial linÕ.
WhÕn a ship is in thÕ dangÕrous
zone, ship spÕÕd should br rÕ-
duáÕd to prÕvÕnt attaák by a
suááÕssion of high wavÕs. CoursÕ
áhange may providÕ anothÕr
mÕthod for Õsáaping thÕ dangÕâ-
ous Zonr, but signifiáant áoursr
áhangÕs arÕ not advisablÕ sináÕ
thÕy will bring thÕ ship to bÕam,
whiáh puts tâansvÕrsr stability
at risk. ThÕ áombination of speÕd
rÕduátion with a slight áoursÕ
áhangÕ is anothÕr possiblÕ taátiá
for Õsáaping thÕ dangÕrous zone.
CarÕ should bÕ takÕn to main.
tain ship spÕÕd for stÕÕrabiliä
in wind and wavÕs.
ShiP course
Fig.4.9 DÕfinition of enáountÕr anglÕ, x
Fig.4-10
DiagÓam indiáating dangÕrous zonÕ of
ÕnáountÕring to high wave group
×,0 2'8 26 2° 22 2'0 |'8 1.6 |'412I'0 0.8
1'4 1,6 l.s z0 22 2.4 2'6 2'8 ×.0
50"
078 I A Guide to ShiP Handling
I
4.1 Ship Hand1ing in FÞllowing and Quarterlng SÕas
RÕduátion of Intaát Stability CausÕd by Riding on WaYÕ CrÕst at Midship
WhÕn a ship is navigating in follÞwing and quaÓtÕring sras, the ÕffÕátivÕ bÕam of a ship-shapÕd hull
áan áhangÕ áonsidÕrably with áhangÕs irr a ship's watÕrlinÕ.profilÕ, partiáularly whÕn thÕ ship has finÕ
linÕs and a|arge flarÕ (áontainÕr shiàs and fishing vÕssÕls).
Thr mÕtaáÕntriá radius, B¼, and áonsÕquÕntly, transvÕrsÕ stability will inárÕasÕ or drárÕasÕ as a wavÕ
passÕs along the lÕngth of the hull. As shown in Fig.4-11, whÕn a ship is riding on thÕ wavÕ árÕst' intaát
stability will bÕ rÕduÞÕd áonsidÕrabl1. as thÕ loss of watÕrplanÕ area at thÕ forÕ and aft Õnds rÕduáÕs thÕ
ship's GM and transvÕrsÕ stÐbiliß-. on thÕ other hand, when thÕ wave trouä is amidships, stability is in-
árÕasÕd as thÕ Õxtra watÕrplanÕ aIÕÐ at thÕ forÕ and aft Õnds inárÕasÕs thÕ ship's G¼ and transversÕ stabili|z.
lffave árest Ðmidships
Sti|l wÐterline
lffave trough amidships
WÐve árest amidships WÐterplane area
':',,:j.:: Still waterline waterplane area
{.:.::j.i=i.i:i..].µ Wave tro u g h am ids h i ps wate rp | Ð n e are a
Fig.4-11 ÁhangÕ in ship,s watÕlplanr arÕa with wavÕ profilÕ
ThÕ amount of stability rÕduátion is nÕarlã propottional to
wavÕ hÕight and thÕ ship may losÕ stability whÕn thÕ wavÕ-
lÕngth is onÕ to two timÕs ship lÕngth and wavÕ hÕight is
largÕ. This situatiÞn is ÕspÕáially dangÕrous in following and
quartÕring sÕas, bÕáausÕ thÕ timÕ spÕnt riding thÕ wavÕ árÕst
bÕáomÕs longÕr (morÕ time is spÕnt in a statÕ of rÕduáÕd sta.
bility). Fig.4-|2 shows thÕ frÕquÕnáy of áapsizing duÕ tÞ rÕ-
duáÕd stability as rÕvÕalÕd by ÕxpÕrimÕnts with ship modÕls.
PlÕasÕ notÕ that thÕ most dangÕrous áapsizing zonÕ rÕlatÕs to
a dirÕátion of ÕnáÞuntÕr wavÕ anglÕ ranging from 20 to 40
dÕsrÕÕs frÞm thÕ stÕrn'
µnÞounter wave ang|e
Fig.4-12
NumbÕr of áaàsizÕd vessels to numbÕr of
trial runs (mÞdel ship ÕxpÕrimÕnts)
Ná: Number of áaàsized vessels
N : Number of trial runs
40
4
40
<Û
Ä
.N
Ä
Ñ
(J
o
(d
E
600/o
40o/o
20%
A Gui de to Shi p HÐndIi ng | 079
!@EEa Ship Handling in WavÕs
RÕduátion of stability tÕnds to bÕ morÕ signifiáant whÕn a ship is finÕ-linÕd with a |arge flarÕ (áontain-
er ships and fishing vÕssÕls) and lÕss signifiáant in full-hull ships (tankÕrs and bulk áarriÕrs).
ÂhÕ fastÕr thÕ ship runs, thÕ grÕatÕr thÕ risk ofáapsizing; rÕduátion ofstability is gâÕatly inárÕasÕd bÕ-
áausÕ thÕ ship is riding on a árest of a largÕr wavÕlÕngth, i.Õ. largÕr wavÕ hÕight. To avoid thÕ risk of
áapsizing due to rÕduáÕd stability, ship speÕd should bÕ rÕduáÕd or áoursr altÕrÕd, or both, in ordÕr to
áhangÕ thÕ ÕnáountÕr Wavr anglÕ and pÕriod. WÊÕn ÕxÕáuting thÕ abovÕ proáedurÕs' áarr should bÕ
takÕn not to induáÕ othÕr risks, suáh as bÕam sÕas that may plaáÕ thÕ dÕák undÕr WatÕr or áausÕ svn-
áhronous rolling motion. ¶*:*+
Synáhronous Rolling MotiÞn
LargÕ rolling motions may bÕ ÕxáitÕd when thÕ nafural rolling pÕriod (TÚ) áoináidÕs with the Õnáoun-
tÕr wavÕ periÞd (TÒ) (Fig.a-l3). WhÕn nÐvigating in following and quartÕring sÕas' this may happÕn if
thÕ transvÕrsÕ stability of thÕ ship is small and, thÕreforÕ, thÕ natural rol1 pÕriod bÕáomÕs longÕr.
Li sti ng.
Return ro|l is aááÕlerated and reinforáed by the neåt Wave.
ÂhÕ Iimits of ship's ro|| áoináide with the Wave árest (or trough).
The rolling angle ináreases with eaáh suááessive wave.
This is known as ..synáhronous ro||ing'', (Causing dangerous heavy ro|ling.)
o
o
I
)80 ] A Guide to ship ÝandIing
I
Fi g.4.13 Sãnáhronousrol l i ng
.:
1.1 Shià Handling in Fol1owing ÐIrd QuartÕrirrg Seas
Fig.4-14 shows thÕ zonÕs of hÕa\ã rolling of ships With 8- and 24-seáond roll pÕriods among wavÕs of
60 to 180 mrtÕrs in lÕngth. As sÕÕn in thÕ ³rgurÕ' thÕ zonÕ of hÕavy rolling shifts from thÕ bÕam to thÕ
quartrr of thÕ ship as thÕ nafural rol1 pÕriod bÕáomÕs lÞngÕr (i.Õ. thÕ ship bÕÞomÕs tÕndÕr.)
ÁoursÕ áhangÕ or spÕÕd rÕduátion is rÕquirÕd to prÕvÕnt synáhronous rolling motion, i.Õ. avoiding syn-
áhronous ro11,ÂÚ/ Tr,:1. ThÕ áoursr or spÕed leading to synáhronous roll áanìe oÌtained using thÕ
Õquation dÕsáribÕd on pagÕ 07 6 or bã thÕ diagram in Fig.4.8 undÕr thÕ áondition TR/ Tµ : l .
l _Âß .1.25\/â
. Ship,s rÕlativÕ áoursÕ to wavÕ ( á ) from thÕ bow
lÕading to synáhronous rolling:
. Ship spÕÕd (Vs m/s) lÕading tÞ synáhronous
rolling motion:
Example
1. Natura| ro||i ng peri od (âÒ) = 24sec (áontÐi ner and Páá)
2. Wave enÞoUnter peri od (ÂÒ)=24seá
3. âR=âµ -synáhronoUs ro||i ng
oâR=24' Vs=15 knots aßd a=159 deg from bow-synáhronoUs rol Ii ng
How to avoid synáhronous rolling
changespeed (vs) o* Ä
Changeáourse (a) 9*g
(Beware quÐrtering seas when changing áourse.)
coSá=
Tß .Vs
l _Tß .1.25\/â
Vs=
TÝ. áosa
·5
30
25
20
I5
10
I
3s
5
µo
Ä
o-
al,
.+5
tro
15
20
25
·0
·5
Foflowing seas Fig.4-L4
ZonÕ Þf hÕavy 'rolling Þf ships with 8- and 24-sÕáond Óoll àÕriods among waves Þf 60- tÞ 1 80.m length
Head seas
wav´s ot uo-,J ',o-' |ength Ðre pl."Ðorni'l,ant ,l' o"Ìo "J"".
Ç
Ä
N
.|³
á
5
.g
á
Ä
-.µ.
Ñ
á
ä
Ä
"1i"
¡
F
.+
=
s
.:
{Ì,'
7 I 910
Natura| period (seá.)
A Guide to ship ÝÐnd|ins | 08.|
E!!!fi Jrl rà fl al rurr'tg l't vta}áD
Surf.riding and Broaáhing.to
WhÕn a ship is situatÕd on thÕ
stÕÕp forÕfront of a wavÕ in fol-
lowing and quartÕring SÕa áon-
ditions, thÕ orbital vÕloáity of
watÕr par1iálÕs áan ÞausÕ thÕ
ship áan to ridÕ thÕ wavÕ, a
phÕnomÕnon known as surf-
riding. In suáh a sitèation (i.Õ.
ship travÕlling down-slopÕ), two
opposing drift foráÕs will árÕ-
atÕ a furning momÕnt as shown
in Fig.4-17.
ThÕ ship is tumÕd foráibly bÕáausÕ of thÕ laák of stÕÕrability' and is tÒ.istÕd bÕam-on to thÕ advanáing
árest of thÕ WavÕ' aS shown in Fig.4-18.
rr+ Force of water paßiá|e motion
Water pÐIhc|e orbita|s
Yawing moment
.> Üomentum
+ Wave direction
Wind & Wave
Fig.4.17 TÓar'Õlling dÞrr'n-slopÕ
0B4 A Guide to ship ÝÐndling
Fig.4-18 ¿lustration ofbroaáhing-to
4. ] Ship Haßálling in FollÞwing aná qu-.".ing s.o,
This is known as broaáhing-to, and thÕ ship is at risk of áapsizing duÕ to thÕ suddÕn áhangÕ ofhÕading
and unÕxpÕátÕdly largÕ hÕÕling. BrÞaáhing-to áan happÕn to small as wÕll as largÕ ships. Broaáhing-to
morÕ áommonlã oááurs whÕn wavÕs aÓrivÕ from bÕhind with a small anglÕ, say 10-30 dÕg., to thÕ forÕ-
and-aft axis of thÕ ship. In modÕratÕ sÕa statÕs, a ship is morÕ likÕly to broaáh-to if it is running at a
high spÕÕd and is slowly ovÕfiakÕn by thÕ wavÕs. Broaáhing-to may also oááur at lowÕr spÕÕds if thÕ
WaVÕS arÕ vrry stÕÕp. As mÕntionÕd abovÕ, whÕn ship spÕÕd is so high that its áomponÕnt in thÕ wavÕ
dirÕátion approaáhÕs thÕ phasÕ vÕloáity ofthÕ wavÕ, ·5
thÕ ship will bÕ aááÕlÕratÕd, wi1l bÕgin surf-riding
and thÕn broaáh-to. ThÕ áritiáal spÕÕd for thÕ oÞáur- ·0
rÕnáÕ of surf-riding is áonsidÕrÕd to bÕ 1.8r/³ Q 25
(knots), whÕrÕ L is ship lÕngth. It should bÕ notÕd 5 ,n
that thÕrÕ is a marginal zone (|.4,,fL-1.8,´) bÕlow Ò ."
áritiáal spÕÕd whÕrÕ a laÓgÕ surgr may oááur. This * ,'
ÕvÕnt is almost ÕquivalÕnt to surf-riding in tÕrms of .µ ,o
dangÕr. Fig.4-19 shows thÕ áritiáal spÕÕd (knots) for á
thÕ oááurrÕnáÕ of surf-riding in rÕlation to ship
lÕngth. Fig.4-20 shows thÕ diagram indiáating surf- 0
riding dangÕrous zonÕs.
To avoid sè¡riding and broaáh-
ing-to, ship spÕÕd shÞuld bÕ rÕ-
duáÕd to thÕ marginal spÕÕd
zofle or bÕlow. AftÕr rÕduáing
spÕÕd, if thÕ ship is in thÕ mar-
gi nÐl zonÕ and a l ÐrgÕ suÓgÕ i s
fÕlt' spÕÕd should bÕ rÕduáÕd
furthÕr' Surf-riding áan oááur
whÕn a ship is running in shal.
low watÕrs, ÕvÕn whÕn thÕ ship
is making a rÕlativÕly low
spÕÕd. This is bÕáausÕ thÕ phasÕ
vÕ|oái ty of wÐvÕs i s sl owÕr i n
shallow WatÕrs, and thÕ áritiáal
spÕÕd may bÕ attainablÕ at a re|-
ativÕly low ship spÕÕd.
lt is important that seÐfarers
operÐting high-speed pleÐs-
ure boats and fi shi ng ves-
sels in shallow waters bear
thi s phenomenon i n mi nd.
·'0 2.8 2'6 2'4 2'2 2.0 I.8 1,61.4 12 |'0 0.8
v/â
0,8 1,0 |,2 1'4 1,6 I.8 20 2'2 24 2,6 z8 ·.0
V: Shi ps speed (knot) T: Wave peri od (seá)
Fig.4-20
Diagrarrr indiáating dangÕrous zÞnÕ duÕ to surf-riding
A Gui de to shi p Ýandl i ns ]
ship Iength (m) Fig.4-19
Áâitiáal spÕÕd fbr suÓf.riding and ship lÕngth
A
0
E@I Shià µ{aÒaá}iimg itlWaves
Ship Motion in HÕad and Bow SÕas
A ship among wavÕs is rÕpÕatÕdly subjÕÞtÕd to hÕaving, pitáhing and rolling as shown in F'ig.4-3.
Hogging, sagging and twisting (torsional momÕnt) áan also bÕ gÕnÕratÕd dÕpÕnding on thÕ ship's rÕla-
tivÕ position to thÕ waves; i.Õ. whÕthÕr thÕ wavÕs árÕst or trough amidships, or thÕ ship is among obli-
quÕ WavÕs as shown in Fig.4-2l and F'ig.4-22.
Hul l twi sti ng
086 A Gui de to Shi p Handl i ng
HulI hogged by wave árest amidships Hul l sagged by wave trough ami dshi ps
Fl g.J-2 ! ½ÞÕgi nr 1l l d sÐgÀ j nc
Fig.4.22 Twisting (torsiÞnal mománt)
4.2 Ship Handling in Hrad and Bow Seas
Compoundin g the above' ship speed is rÕduÞÕd due to added fesistanáÕ fuom wind and waves.
This phÕnomrnon is ÕspÕáially likely in hÕad and bow sÕas.
A ship's pitáhing responsr to anà wavÕ is dÕtÕrminÕd by thÕ Ùave's ÕnáountÕr length rÕlativÕ to the
shipÊ lÕngth' as well as the period of Õnáountrr:
. ThÕ ship's pitching motion is lÕss signifiáant whrn wavÕlÕngth is shortÕr than ship lÕngth bÕáausÕ thÕ
influenáÕ wavÕ is small. Pitáhing is rÕstrainÕd; thÕ bottom of thÕ bow doÕs not ÕmrrgÕ from thÕ wa-
tÕæ and thÕ bow doÕs not dip sÕverÕly Õnough to takÕ grÕÕn watÕr. (Fig.a-23)
o WhÕn wavÕlÕngth is longÕr than ship lÕngth, thÕ ship pitáhÕs and hÕavÕs Õasily following thÕ fore and
aft wavÕ profilÕ. (Fig.a-2a)
Þ WhÕn wavelÕngth is Õqual to ship lÕngth pitáhing motion is at its most intÕnsÕ. HÕaving of thÕ ship
on a árÕst and plunging of thÕ bow into thÕ nÕxt wavÕ will aááÕlÕratÕ. Fluátuations of WatÕr lÕvÕls rÕ1-
ativÕ to wavÕs at thÕ bow and stÕrn gâow grÕatÕæ lÕading to phenomÕna suáh as propellÕr racing,
shipping watÕr and slamming. (Fig.a-25)
Fig.4.23 Pitáhing motion when enáountÕr wavÕlñngth is shortÕr than ship length
Fig.4.24 Pitáhing motion whÕn ÕnáountÕr wavÕlÕngth is longÕr than ship lÕngth
Fig.4-25 Pitáhing motion whÕn enáountÕr wavÕlength is equÐl tÞ ship tength
A Guide to ship Ýandling l
i
Eftfil!f, Ship Handling in WavÕs
Fig.4-26 shows thÕ áaláulatÕd fluátuations of
watÕr lÕvÕl rÕlativÕ to Wavrs at thÕ bow.
From thÕ ³rgurÕ, it is known that thÕ fluátuat-
ing watÕr lÕvÕl at thÕ bÞw attains its grÕatÕSt
lÕvÕl whÕn wavÕlÕngth is Õqual to ship lÕngth;
shipping ofwatÕr áan oááur bÕáausÕ thÕ rÕla-
tivÕ watÕr lÕvÕl ÕxáÕÕds thÕ bow frÕÕboard;
slamming áan oááur whÕn thÕ rÕlativÕ watÕr
lÕvÕl drops far Õnough bÕlow for.ward draft to
ÕxposÕ thÕ bottom platÕs at thÕ bow.
Ä
Ä
Ä
Ñ
×
Ä
Ñ
Ä
µ
WhÕnÕvÕr a ship is pitáhing and hÕaving hÕavily at thÕ bow, similar hÕaving motion is gÕnÕratÕd at
thÕ stÕrn. As thÕ rÕlativÕ motion bÕtwÕÕn watÕr lÕvÕl and thÕ stÕrn inárÕasÕs. thÕ stÕrn lifts out of thÕ
watÕr and Õåposrs part ofthÕ propÕllÕr, áausing it to raáÕ. This grÕat and abrupt ÓÕduátion ofpropÕl-
lÕr load rÕsults in a suddÕn inárÕasÕ in propÕllÕr rÕvolutions, gÕnÕrating intÕnsÕ r.ibration. Known as
propÕllÕr raáing, this phÕnÞmÕnon áan damagÕ thÕ propÕllÕr' thÕ propÕl1Õr shait and thÕ main ÕnginÕ'
Aááordingly, whÕn a ship in ballast is navigating hÕad and bow sÕas in still rr'atÕrs. aft draft should bÕ
dÕÕpÕnÕd so that thÕ ratio of propÕllÕr immÕrsion to propÕllÕr diamÕtÕr may bÕ kÕpt at 20 pÕráÕnt or
morÕ. (Fig.4-27)
PropÕllÕr Raáing and RÕduátion Þf Ship SpÕÕd
lmmersed depth of propellerr upper tip ratio
d/D > o.2(2ÄÌ)
Propel l er i mmersi on rati o
I lD > o.7 (7oã")
I : propeller immersion D: propeller diameter
1.0 2.5
Wavel ength / Shi p l ength
Fig.4-26 FluátuatiÞl-ls tli ÓÕ1attr Õ l'u'atÕr lÕvÕ1 at bÞw
Fig.A-27
RÕá1uiâÕd ratio of pâopÕllÕr immÕrsion to pr.álpÕllÕr diamrtÕr
Draft at bow
Freeboard at bow
0B8 | A Gui de to Shi p HÐnd|i ng
I
4.2 Ship Handling in HÕad and Bow SÕas
PlÕasÕ also notÕ that nominal spÕed will bÕ rÕduáÕd duÕ to addÕd resistanáÕ, IÕduáÕd propulsivÕ ÕfÂi-
áiÕnáy and inárÕasÕd proprller load. Fig.4-28 shows thÕ nominal spÕÕd rÕduátion in ièÕgu1ar wavÕs
Whrn a 250-m-lÞng áontainÕr ship hÕads into a sÕaway. ThÕ figurÕ makÕs it álÕar that thÕ dÕgrÕÕ of
nominal spÕÕd rÕduátion inárÕasÕs signifiáantly whÕn wavÕ hÕight ÕåáÕÕds 6 mÕtÕrs.
Fig.4-28
Nominal sàeed rÕduátion in hÕad sÕas
(full-1oaded áontainÕr ship)
WhÕn thÕ main ÕnginÕ is subjÕát to ÕxáÕssivÕ torquÕ brought about by addÕd rÕsistanáÕ to thÕ hull, thÕ
rÕsult áan bÕ what is known as a torque riáh áondition, whiáh áan lÕad to ÕnginÕ troublÕ áausÕd by
ovÕrhÕating, or in abnormal áÞnsumption of fuÕl oil. In suáh an ÕvÕnt, ship spÕÕd must bÕ rÕduáÕd.
Shir headißg tÞ high waves
µ 1n
µ
µ
í
ç n°
;
Ä
Ä
Þ-
(I)
0.2
Wave height 1m;
A Gui de to shi p ÝÐndIi ng | (
!@[s@ ShipHandlinginWavÕs
Shipping Water Forward
Shipping watÕr rÕfÕrs to grÕÕn watÕr swÕÕping down thÕ upper dÕáks bÕyond thÕ forÕáastlÕ bulwark.
ThÕ impaát foráÕ of grÕÕn WatÕr áan áausr sÕvÕrÕ damagÕ. oááasionally, dÕák maáhinÕry dÕák áargo
and hatáh áovÕIS arÕ damagÕd. Hatáh áovÕr damagÕ may allow watÕr to ÕntÕr into thÕ holds.
ThÕ impaát foráÕ of shipping watÕr has two ÕffÕáts: dirÕát dynamiá prÕssurÕ árÕatÕd by thÕ shippÕd
grÕÕn watÕr; and impaát foráÕ áausÕd by thÕ swÕÕp of grÕÕn watÕr against dÕák maáhinÕry and othÕr
applianáÕs. Dynamiá prÕssrrrÕ árÕatÕd by shippÕd grrÕn WatÕr pounding onto thÕ dÕák can rÕaÞh ap-
proåimatÕly twiáÕ the statiá prÕssurÕ ÕquivalÕnt to hÕight of shippÕd grÕÕn watÕr abovÕ dÕák. ThÕ dy-
namiá strÕss of shippÕd grrÕn WatÕr swÕÕping ÞvÕr thÕ dÕáks is prÞportional to thÕ squarÕ Þf ship
spÕÕd; impaát foráÕ is similar tÞ that áausÕd by grÕÕn watÕr pounding thÕ dÕák.
Fig.4-29 shows thÕ rÕsults Þf a tank tÕst on
shipping watÕr. AssumÕd arÕ an aáfual ship of
78.5-m lÕngth and rÕgular rvavÕs of3-m hÕight
(áorrÕsponding to BÕaufort sáale ·). ThÕ ex-
pÕrimÕnts wÕrÕ ÕxÕáutÕd in áombinatiÞn with
various ship spÕÕds, wavÕ ÕnáountÕr anglÕs and
ratios of wavÕlÕngth to ship lrngth.
From thÕ figrèÕ, it is found that shipping watÕr
inárÕasÕs whÕn ship lÕngth is Õqual to wavr-
lÕngth in hÕad sÕas, and that thÕ frÕquÕnáy of
shipping WatÕr may bÕ dÕárÕasÕd by rÕduáing
spÕÕd andlor altÕÓing áoursÕ.
Fig.4-29 FrÕquÕnáy of shipping watÕr in regular wavÕs
As shÞwn in Fig.4-30, oáÕan WavÕs áan bÕ sÕÕn aS a supÕlpo-
sition of many, simplÕ, regll|at harmoniá wavÕ áomponÕnts,
Õaáh with its own amplitudÕ, lÕngth or frÕquÕnáy and dirÕá-
tion ofpropagation.
ThÕ intÕraátion of thÕsÕ áomponÕnts áan lÕad to irrÕgulariä.
NÕÕdlÕss to say, it is important to invÕstigatÕ shipping watÕr
phÕnÞmÕnon in irrÕgular WavÕs.
Fig.4-30
ÁonáÕpt of irâÕgular wavÕ
-30"
ang\e
090 i A Guide to ship ÝÐnd|ing
4.2 Ship HandIing in HÕad and Bow SÕas
Fig.4-3l shows thÕ rÕsult of shipping watÕr
tÕsts. AssumÕd arÕ a shi p of 78.5-m l Õngth
and irrÕgular WavÕs. From thÕ figurÕ, it áan
bÕ seÕn that the frÕquÕnáy of shipping watÕr
inárÕasÕs proportionally with an inárÕasÕ in
ship speÕd and dÕáreasÕs as thÕ ÕnáountÕr
wavÕ anglÕ (mÕasurÕd from thÕ bow) inárÕasÕs.
WhÕn áonsidÕring shipping watrr phÕnomÕn-
on in hÕad and bow seas, first áheák thÕ
BÕaufort sáalÕ numbÕæ whiáh rÕlatÕs to thÕ
hÕight of áorrÕsponding wavÕs, to áaláulatÕ
thÕ frÕquÕnáy of shipping WatÕr' as shown in
TablÕ 4.1. (ÂhÕ BÕaufort sáalÕ will bÕ Õx-
plainÕd in ChaptÕr 5.) NÕxt, using probability
thÕory a áritiáal oprration diagram for thÕ oá-
áuèÕnáÕ of shipping watÕr áan bÕ obtainÕd.
TablÕ 4-1 BÕaufort sáalÕ and wavÕ hÕight
Fig.4-·2 and Fig.4.33 show áritiáal opÕration diagrams for thÕ oááurâÕnár of shipping watÕr for a full-
loadÕd áontainÕr ship of40,000 gâoss tons. Ship spÕÕds arÕ drawn in áonáÕntriá áirálÕs and enáountÕr
wavÕ anglÕs in radial lines. Critiáal lines áorrÕsponding to thÕ BÕaufort sáalÕ (wavÕ hÕight) arÕ shown
as áolorÕd áurvÕs.
Contai ner shi p
Contai ner shi p
Ö'F 1-a .;. .; u .i... Ò 9.'.. l o l ti t..l z
H"i;fr!*, .lo.í'Þ ×.o +µ 5'5, ;i.. s.o âl.i:lÔ.Þ
Ñ'×
.:'=
_Þ
(knots)
Fig.4-32
Critiáal opÕration diagram for thÕ ÞááurrÕnáÕ Þf
shipping water on a áontainÕr ship (l0 times/hour)
Fig.4-31
FrÕquenáy of shipping watÕr in iÓregular wavÕs
Fréuenry of shiàing Water
=5 ti mes/hour
5'o lo 15 20 25 (knots)
Fig.4-33
CritiáÐl Þperation diÐgâÐm for thÕ oááuÓÓÕnáe of
shipping watÕr Þn a áÞntainer ship (5 times/hour)
1,1lquÒ
Frequenáy of shiàing Water
=10 ti mes/hour
Ä
j Ç^
åÇ
t
.À ln
í l w
Äl l
Ä..
11
tz
Ev
±l U
í 11
Ñ l I
Ä-^
Ä12
A Gæide to shià ÝÐndIing I
I
EEEé Shià HÐndling in WavÕs
ThÕsÕ figuâÕs show that a áontainÕr ship hÕading into a seaway with BÕaufort sáalÕ 10 wavÕs will ship
watÕr l0 timÕs pÕr hour at a vÕssÕl speed of 19 knots (F'ig.4-32), and that thÕ frÕquÕnáy of shipping wa-
tÕr áan bÕ áut in half i.Õ. to 5 timÕs pÕr hour, if ship spÕÕd is ÓÕduáÕd to l7 knots. (F.ig.a-33)
By thÕ samÕ tokÕn, a full-loadÕd orr áarriÕr of l10,000 gross tons hÕading into a sÕaway of BÕaufort
sáale 5 áan rÕduáÕ thÕ frÕquÕnáã of shipping watÕr by half, from l0 timÕs pÕr hour to 5 timrs pÕr hour,
if ship spÕed is rÕduáÕd from l3.5 knots to l2.5 knots. (Fig.a-3a' F'ig.4-35)
ore áarrier
ore áarrier
Frequenry of shiàing waµr
=5 times/hour
Êu
3.0 6.0 9.0 12 J5(knots)
Fig.4-34
J5(knots)
Fig.4-35
. Frequenáy of shipdng wder
ãTQuo =10 times/hour
- etL
\ 't%
--å \ lÓo "2
Ä
()
Ä
o
×
o
Ä
Critiáal opÕration diagram for the ÞááurrÕnáe of
shipping watÕr on Ðn ore áÐrriÕÓ (10 times/hour)
CritiáÐl opÕration diagram foÓ the oááurÓenáe of
shipping watÕr on an orÕ áarÓiÕr (5 timÕs/hour)
ThÕ oááurrÕnáÕ of shipping watÕr as it rÕ.
latÕs to ship äpÕ and spÕÕd is summarÙÕd
in TablÕ 4-2. It is shown that a rÕduátion
of spÕÕd will áonsidÕrably lÕssÕn shipping
watrr.
Frcquencyofshiàpingwater Bf.5
10 times/lrour 12 knots
5 times/hou] 11 kßots
*Bf = Beaufort sáa|e
Ship typÕs and speeds for thÕ oááuÓrÕnáÕ of shipping water
Slamming
WhÕn a ship proáÕÕds at a rÕlafivÕly high spÕÕd in hÕad sÕas, slamming may oáárrr. Slamming may bÕ
álassifiÕd into thÕ following thrÕÕ typÕs:
. Òottom sIÐmming oááurs whÕn, due
to hÕavy bow motion rÕlativÕ to WavÕs,
thÕ forward part of a ship's bottom
ÕmÕrgÕs from the Water and thÕn slams
down hÕavily into the rising watrr of thÕ
nÕxt onáoming wavÕ. (Fig.4-3Ñ)
Fig.4-3Ñ Bottomslamming
092 | A Guide to Ship HÐßdling
I
4.2 Ship Handlirrg in HÕad and Bow SÕas
. BoW flare slamming oááurs tn a Iarge flarÕd ship WhÕn a high rÕlativÕ spÕÕd Õxists bÕtwÕÕn watÕr
lÕvÕl and thÕ flarÕ. (F.ig.4-37)
Fig.l-×ß BÞw flÐrÕ slamrning
. Breaking Wave impaát is áausÕd by thÕ build-uà
of brÕaking wavÕs rÕsulting from a supÕrposition of
bÞw wavÕs and hÕad sÕas. LargÕ, fat ships arr sus.
áÕptiblÕ to this phÕnomÕnon. (Fig.a-3s)
Fig.4-38 BrÕaking WatÕr (WaVÕ) lmpaát
HÕalã slamming will not only damagÕ thÕ ship's boé forward bottom plating and bow flarÕ, but thÕ
áargo as well. ImmÕdiatÕly aftÕr slamming, high-frÕquÕnáy vibratory strÕssÕS, áallÕd whipping, will
takÕ plaáÕ ÕlsÕwhÕrÕ in thÕ hull, áausing damagÕ to thÕ hull and various applianáÕs.
FurthÕrmorÕ' as thÕ frÕquÕnáy of slamming inárÕasÕs, áraáks áan dÕvÕlop in thÕ hull struáturÕ and mÕt-
al fatigue, áausÕd by rÕpÕatÕd strÕssÕs and strains, oááasionally rÕsults in fbta1 hull áollaÞsÕ.
Phoios äUrtesy of Aáâ áo' Ltd'
A Gui de to shi p ÝÐndl i ng ] 0s
I
zl.2 Ship Handling in HÕad and Bow SÕas
E!!s[l Ship Handling in waves
Fig.4-39 shows modÕl ÕxpÕrimÕnts áoncÕming a
78.5-mJong vÕssÕl ÕxpÕriÕnÞing slamming.
ThÕ following impor1ant findings have bÕÕn ob-
tainÕd:
. AppropriatÕ rÕduátion of spÕÕd is ÕffÕátivÕ rn
rÕduáing slamming.
. AltÕring áoursÕ to áhangÕ ÕnáountÕr anglÕ is
also ÕffÕátivÕ in rÕduáing slamming.
. A ship in light áondition with trim-by-thÕ-stÕrn
is mÞrÕ susÞÕptiblÕ to slamming áomparÕd to a
ship in full-load áondition.
. Slamming is likÕly whÕn thÕ ship is álosÕ to
rrsonant pitáhing in hÕad wavÕs slightly lÞngÕr
than its own lÕngth.
CarÕ should bÕ takÕn whÕn rÕduáing spÕÕd or
áhanging áoursÕ as thÕsÕ mÕasulÕs may have
áonsrquÕnárs with rÕgard to paramÕtriá rolling,
synáhronous rolling or áoursÕ áontrol.
Fig.4-40 shows a áritiáal opÕration diagram for
slamming on a full-loadÕd containÕr ship of
40'000 gross tons. ThÕ figurÕ shows that a áon-
tainÕâ ship hÕading intÞ a sÕaway of BÕaufort
sáalÕ 10 (avÕragÕ wavÕ hÕight 9 mÕtÕrs) will suf-
fÕr slamming 2 timÕs pÕr hour if thÕ ship is mak-
ing 13 knots. (WhÕn áoursÕ is altÕrÕd to 45 dÕ-
grÕÕs starboard or port' thÕ ship áan makÕ 19
knots.)
oááuèÕnáÕ of slamming rÕlativÕ to ship äpÕ and
sÞÕÕd is ÕxaminÕd in Table 4-3.
In this áhaptÕæ you havÕ bÕÕn shown many tablÕs and diagrams
hÕalã sÕas and found thÕsÕ rÕfÕrÕnáÕs to bÕ :: .:..:.j.:|:.|::::|.::I:::.:::
simplÕ and áonvÕniÕnt mrasurÕs. MorÕovÕr,
rÕfÕrÕnáÕ data ate now availablÕ for naviga-
tiÞnal risk phÕnomÕna as thÕy rÕlatÕ to ship 5 times/hour
typÕs and áonditions. It is hopÕd that you arÕ 2times/hour
ÕnáouragÕd to aÞhiÕvÕ sÐfÕ nÐvigation in *Bf = BeÐufoÓt sáa|e
Fig.4-39
FÓÕquÕná1-of slamming on a áoastal ship
in light áÞndition
Contai ner shi p
Frequenáy of sl ammi ng
=2 ti mes/hour
5.0 l0 15 20 25(knots)
Fig.4-40
CÓitiáal opÕratiÞn diagram for thÕ oááurrenáÕ of
slamming Þn a áontainÕr ship (2 timÕs/hour)
for avÞiding navigational risks in
.. .;.;;;Ùi×;¡ : .á;;ntn*:.:':oµ. .l
á
-
Ä
Ä
()
á
Ä
í
Ä
LL
Ä
6
3o
á-,
±
(g
Ä
Ä1n
11
1)
hÕalã sÕas by using thÕsÕ rÕfÕrÕnáÕ data.
094 A Guide to ship ÝÐnd|ing
Ship typÕs and spÕÕds for thÕ ocáurâÕnáÕ of slamming
@
ñ.;*,**q**ffi
¼ÕtÕÞrÞIÞgã fÞr SafÕ Navigation in
µxtratrÞpiáal axld
Âropiáal CãálÞnÕs (StÞrms)
"d't'
:'s;J
*.*:i
ffi
4
ff
"r&t
..t.
* : 1,,,
. 'j,
r, 1
, -::
tt
:.
F
t
I
r¡ nrt
"í'Æ*i
.,_: - :
y6lÞg! for SafÕ Navigation in
*Ò.qÚmland
:.,
TfÞpiáal CãálonÕs (Storms)
Beaufort SáalÕ (PrÕliminary GuidanáÕ)
ThÕ BÕaufor1 sáalÕ is an Õmpiriáal mrasurÕ dÕsáribing wind intÕnsity basÕd mainly on obsÕrvÕd sÕa áon-
ditions. It is usÕd by áountlÕss wÕathÕr stations and sÕafarÕrs. A dÕfinition ofthÕ BÕaufÞrt sáalÕ is shown
in TablÕ 5-l, whilÕ Fig.5-1 providÕs a visual imprÕssion of thÕ sÕa statÕs rÕlativÕ to thÕ BÕaufor1 sáalÕ.
@.t,"
Beauforl
nuÙber
Wind speed (mls)
Probable mean
Wave height (Ä
Sea áondition
0 0-0.2 Cal m
0
ÞaIm (GIassy)
1
0.×-1.5
Li ght ai r 0.1 Ripple without crests
Z
1.6-×.3 Light breeze 0.2 Sma|I waveIets' árests of gIassy appearanáe
a
×.4-5.4
Gentle breeze
u.o
Large wavelets. Crests begins to break
4
5.5-7.9
Moderate breeze
,1
Smal l waves, becomi ng l onger
5
8.0-10.7
Fresh breeze
Z
l\,4oderate waves, taking a more pronounced long form
o
10.8-13.8 Strong breezÕ Large waves with foam Ðnd sàray
-7
1·.9-17.1
Near gale 4
Sea heaps up and foam begins to streak
I 17.2-20.7 Gal e
b.5
Moderate high waves with breaking crests forming
spindrift. Streaks of foam
20.8-24.4 Strong gale
7
High waves With dense foÐm.
Wave crests start to roll over.
10
24.5-28.4 Storm I
Very high waves with |ong overhanging árests
'11
28.5-t2.6 Violent storm
1 1.5 µxáeptionaIly high Waves: VisibiIity affeáted
12
·2.7ove(
Hurriáane
14+
The air is filled with foam and sDrav:
VisibiIity serioUsly affeáted
TabIÕ 5-1 BÕaut.ÞÓt r'r,ind sáalá
096 A Gui de to Shi p l l andl i ng
Fig.5.1 sÕa statÕ vs bÕaufort sáalÕ
Photos áourtesy d{ Japan t\4eteoroIogiáÐ| °gency
A Guide to ship ÝÐndlins 097
I
I
I
Fig.5.1. . SÕa statÕ r,s bÕÐufort sáalÕ
Photos áourtesy of. Jaàan ¼eteo'olÑgiáal .Ageßcy.
)98 | A Gui de to $hi p Handl i ns
5.1 MetÕorologiáal PhÕnomÕna ln WzrtÕrs NeighÌoring Jaàan
Formation and DÕvÕlopmÕnt of µåtratrÞpiáal CyálonÕs and Typhoons
1. Formation and deveIopment of extratropiáaI áyclones in waters neighboring Japan
ThÕ formation and dÕvÕlopmÕnt of Õåtratropiáal áyálonÕs arÕ grÕatly affeátÕd by air massÕs in watÕrs
nÕighboring Japan. WhÕn a\ area of high atmosphÕriá prÕssurÕ rÕmains ovÕr a áontinÕnt or thÕ oáÕan
for an ÕxtÕndÕd pÕriod of timÕ' a largÕ homogÕnÕous air áonáÕntration may build up. This is áallÕd
an air mass. ThÕrÕ arÕ two major air massÕs affÕáting mÕtÕorologiáal áonditions in watÕrs nÕighbor-
ing Japan: onÕ is thÕ SibÕrian Air Mass, a áold air mass; and thÕ othÕr is thÕ ogasawara Q.{orth Paáif-
iá) Air ¼ass, a warm air mass. DÕpÕnding on thÕ sÕason, thr okhotsk Air ¼ass and thÕ YangtzÕ-Riv-
Õr Air Mass will also influÕnáÕ mÕtÕorologiáal áonditions in watÕrs nÕighbÞring Japan (Fig.5-2).
Fig.S-2 Air massÕs arÞund Jaàan
A Gui de to shi p ÝÐndIi ng
@MÕtÕorol ogyforSafÕNavi gati oni nµåtratropi áal andTropi áal Cyál onÕs(StÞrms,1
The formation and dÕvÕlopmÕnt of Õxtratropiáal áyálonÕs arÕ ÕxplainÕd as follows: WliÕn two air
massrs with physiáally diffÕrÕnt áharaátÕristiás áomr into áontaát with Õaáh othÕr, fronts are formÕd
in thÕ boundary zonÕ bÕtwÕÕn thÕ two aiâ massÕs.
WhÕn thÕ áold air mass is largÕæ it movrs
towards thÕ warm air mass' thÕ áold air
moving thÕ frontal boundary forward and
raising thÕ lightÕr warm air. A front
formÕd i n thi s mannÕr i s áal l Õd a ..áol d
front" (Fig.5-3).
WhÕn warm air prÕdominatÕs, thÕ warm
air movÕs towards thÕ áold aiâ mass and
pushÕs thÕ front forwÐrd with thÕ lightÕr
warm air árÕÕping up thÕ frontal boundary
of thÕ áold air mass. A front formÕd in this
mannÕr is áallÕd a,,warmfront'' (F.ig.5-4).
cB: áumuIonimbus
NS: nimbostratus
An Õåtratropiáal áyálonÕ fÞrms whrrÕ thÕsÕ fronts mÕet. WhÕn a southÕm warm air mass movÕs north-
ward and a northÕrn áold air mass movÕs southward, an updraft is árÕatÕd by thÕ áontaát bÕtwÕÕn thÕ
two air massÕs (Fig.5-5).
100 | A Gui de to Shi p Handl i ng
5.1 MÕtÕorologiáal PhÕnomena in WatÕrs NeighboÓing Japan
As shown in F'ig.S-Ñ, this forms the countÕr-áloákwisÕ spiral flow of aiâ that áan dÕvrlop into an Õxtra-
tropica| cãclone.
ThÕ largÕr thÕ diffÕrenáÕ il tÕmprÓÐnèÕ bÕtwÕÕn thÕ two áonverging massÕs' the grÕatÕr the potÕntial
strÕngth ofthÕ Õxtratropiáal áyálÞnÕ. For thÌ rÕÐson' strong Õxtratropiáal áyálonÕs arÕ morÕ frÕquÕnt
in wintÕr than in summÕr.
µåtratÓopiáal áyálonÕs in thÕ NorthÕm hÕmisphÕrÕ gÕnÕrally movÕ nÞrthÕastward at an approximatÕ
spÕÕd of 40 km,/h or daily l0 dÕgrÕÕs of longièdÕ. ApproximatÕ maximum wind spÕÕd may bÕ áaláu-
latÕd using thÕ following formula:
V 1mls1 = $y'1ffi-p Y:TlT"'wind speed (m/s)
P: atmospheriÞ minimum pressure (hPa)
µåtratropiáal áyálones may bÕ álassifiÕd into thÕ following two ÞlassÕs:
. Wind rain álass: áore atrnosphÕriá prÕssrÓÕ is l,000 hPa or less èrd maximum wind spÕed is 15 m/s
or grÕater.
Þ StoÓmy wind and rain álass: áorÕ atmosäÕriá prÕssurÕ is 980 hPa or lÕss and maximum wind spÕÕd
is 25 m/s or grÕatÕr.
A dÕvÕloping Õxtratropiáal áyálone is áharaátÕrizÕd by thÕ following indiáafions:
Þ áorÕ atmosphÕriá prÕssurÕ falls bÕlow l,000 hPa
. ratÕ ofdailyprrssrrrÕ dÕárÕasÕ ÕåcÕÕds 10 hPa
. moving vÕloáity ÕxáÕÕds 50 km/h
Þ AC = StatioßÐry surfaá₠ boundary
or front
¾ srnÐ|. wave developing at B
¾ Ciráu|Ðtion Ðround
AB = Cold front
BC = Warm front
Fig.5.Ñ
Formation of fronts in NorthÕm hemispherÕ
A Guido to ship Ýand|ing | 10
E!!!@ MeteorÞlogy for SÐfÕ NavigatiÞn in µåtratropiáal and TrÞpiáal CyálonÕs (Storms)
2. Suffaáe and upper air weather chafts
ThÕ wÕll-known surfaáÕ wÕathÕr áharts arÕ usÕd tÞ
find thÕ loáatiÞn and strÕngth oflow and high prÕs-
surÕ systÕms as wÕll as Warân' áold and stationary
fronts. ThÕ highs and lows áan bÕ loáatÕd with H
and l sãmbÞls on thÕ map. IsolinÕs rÕprÕsÕnt thÕ
isobars of surfaáÕ atmosphÕriá prÕssrrrr (Fig.5-7).
H: ½igh pressure l.: Lowpressure
To undÕrstand mÕtÕorologiáal phÕnomena áausÕd by Õxtratropiáal áyálonÕs, it is nÕáÕssary to grasp
thÕ thâÕÕ-dimÕnsional struáfurrs of atmosphÕÓiá air movÕmÕnt within thÕ troposphÕrÕ, thÕ lowÕst rÕ-
gion of thÕ atmosphÕrÕ, whiáh ÕxtÕnds from thr planÕt's surfaÞÕ to a hÕight of about |2 k{fi. UppÕr Ðir
wÕathÕr áharts arÕ produáÕd for thÕ portion of thÕ atmosphÕrÕ abovÕ thÕ lowÕr trÞposphÕrÕ; prÕssurr
surfaáÕ hÕight, air tÕmpÕraturÕ and wind spÕÕd arÕ plottÕd on thesÕ isobariá maps. ThÕy arÕ álassifiÕd
into thÕ following lÕvÕls of thÕ atmÞsphÕrÕ (SÕÕ Fig.5-8):
300 hPÐ
(9,000m)
500 hPa
(5,500m)
Ö*,.
Mt.Fuji
Judgement of rain arÕa
Fig.5.7 Surfaáe wÕathÕr áhart
Mt.µVerest
1O2 | A Gui de to Shi p Handl i ng
I
Fig.5.8 Upper air áhaÓts vs. altitudÕs
5.1 MÕtÕÞrÞlogiáal PhÕnomÕna in WatÕè NÕighÜ.Øg ré"n
ThÕ áhar1s rÕprrsÕnt hÕight Þontours
(linÕs ÞonnÕáting all points on thÕ sur-
faáÕ having thÕ samÕ altitudÕ) as solid
linÕs; and isothÕrms (linÕs ÞonnÕáting
all points having thÕ samÕ tÕmpÕra-
turÕ) as dottÕd linÕs (Fig.5-9 and
Fi g.s-10).
300 hPa áharts may havÕ ,,isotaáhÕs'',
whiáh arÕ linÕs áonnÕáting all poiÛts
having Õqual wind spÕÕd. Ships mainly
áonáÕm thÕmsÕlvÕs with 500 hPa up-
pÕr air áharts rÕprÕsrnting wÕathÕr
áonditions in thÕ mid-troposphÕrÕ; half
thÕ mass of thÕ atmosphÕrÕ liÕs bÕlow
this lÕvÕl. SináÕ many wÕathÕr systrms
follow the wind flow at this lÕvÕl, this
lÕvÕl is oftÕn áÞnsidÕrÕd to symbolizÕ
thÕ stÕÕring lÕvÕl Þf thÕsÕ systÕms.
i i 5580
Fi g.5.9 UàpÕr ajÓ áhaßs (500 hPa;
Sol i d l i ne:
IsobariÞ surface / Height (m)
Dotted line;
lsotherms (500/700/850 hPa chart)
Isotaches (300 hPÐ)
W, Core of warm air
C: Core of áo|d air
âemperature
11 -37.5
ç
r.:.,... ,. . . .4;0.' .
;;Dqé' point.deàression
.{iAirtñmp - DeW point temà}
-\
[-;
,ê:
Fi g.S. l 0 UppÕÓ ai r áhafi s (500 hPa: i sobaÓi á sufaáÕ and i soäÕrms)
i' ..,^
._--__-_-Êff*l
!,z N-,+.ï .- '
:,} é-,+.s i'
í;,17-*Ô₠:¡
Þourtesy of Japan Üeteoro|ogiáal Agenáy
A Gui de to shi p ÝÐndl i ng ]
Eéµ Ni IetÕorÞl og1.for Sal Ê Nal,i gati on i n µåtratrÞpi áal and Âropi áal Á1,ál ÞnÕs (StÞrms)
As shown in F.ig.5.1l, Õåtratropiáal áyálonÕs tÕnd to dÕvÕlop in front of an uppÕr.lÕvÕl trough.
WhÕn thÕ uppÕr-lÕvÕl trough dÕÕpÕns rÕlativÕ to thÕ prÕvious day, thÕ low on thÕ surfaÞÕ will
strÕngthÕn.
AttÕntion should also bÕ givÕn to thÕ movÕmÕnt of uppÕr-lÕvÕl isothÕrms, bÕáausÕ thÕ flow of áold air
towards thÕ south may áausÕ Õåtratropiáal áyálonÕs to dÕvÕlop aááÞmpaniÕd with gusting winds.
Partiáular áarÕ should bÕ paid to thÕ movÕmÕnts of isothÕflns on 500 hPa uppÕr-aiÓ áharts at -30.Á and
-36"C in wintÕæ and at -24"Á in spring and Ðutumn (Fig.5-12).
It is hopÕd that navigators will rnakÕ optimum usÕ of uppÕr-air áhar1s in áombination with surfaáÕ
wÕathÕr áharts.
Fi g.5-11 tJpàÕÓ-l Õr.Õl trál ugh l i i Ó t's. l otv Þn suÓl.Ðáá Fi g.5-12 DÕr'.Õl opßl Õl tt ÞI.áåtÓl ttÓál pi áal áãái tl ná
aßtl Lr111l áÓ áÞl d ai Ó i n³l Lrå
3. Âyphoons
Lows formÕd in a tropiáal zone are áallÕd tropiáal dÕprÕssions. In Japan' a tropiáal dÕprÕssion with a
maximum wind spÕÕd of 11 .2 m/s or morÕ is áallÕd a äphoon (Fig.s-l3).
l | Û ául oe to shi p ÝÐnd|i ng
Photos Þourtesy of Japan MeteoroIogica| Agency
.5.l ¼ÕtÕorologiáll PhÕßÞßrÕna in Watárs èÕighì.ing l^àon
Fig.5-l4 shows arÕas of typhoon for-
mation. ThÕ most typhoons form in thÕ
ÕastÕffl sra arÕa off thÕ PhilippinÕ Is-
lands.
As shown in Fig.S-l5, typhoons gÕnÕr.
ally follow onÕ of two paths: somÕ
movÕ nofthwÕstÕrly aftÕr birth; whilÕ
othÕrs vÕÕr to thÕ right along thÕ wÕst-
Õrn fringÕ of thÕ North Paáifiá oáÕan
High, thÕn movÕ nofihÕastÕrly undÕr
thÕ impaát of thÕ WÕstÕrliÕs. ThÕ path
of thÕ lattÕr typÕ is largÕly dÕpÕndÕnt
on thÕ strÕngth of thÕ WÕstÕrliÕs and thÕ
North Paáifiá oáÕan High.
Most typhoons tÕnd to advanáÕ toward
thÕ right, along 500 hPa uppÕr-air áhar1
áontours 5,820 m to 5,860 m for thÕ
Nor1h Paáifiá oáÕan High. Points of
vÕÕr tÕnd to áorrÕspond to thÕ hÕight
ridgÕs for thÕ Nor1h Paáifiá High Õx-
tÕnding Õast to wÕst on thÕ samÕ air
áhart (Fi g.5-1Ñ).
';
Fi g.5-16 °dr.anái ßg áÞuÓsá anál l -áául\,i l 1tl ÓÕ poi ßr ál i tãphÞon
Frequent region S--A Most frequent region
Fi g.5.14 ArÕaso1.tãphÞál nfoÓmati on
Fi g.5-15 Paths Þf typhtl ons
A Gæi de to Shi p HandIi ng 105
@NIÕtÕrl rtl l ÞgyfÞrSÐ1ÊNavi gÐti Þni nµåtratrÞpi áal andTrÞpi áal Á1,ál ÞnÕs(StÞrms)
Typiáal µåtratropiáal CyálonÕs DÕvÕloping in WatÕrs Neighboring Japan
:Li
.:;
ÞoUrtesy of Japan |\,4eteoroIogiáaI Agenáy
In watÕrs nÕi ghbori ng Japan, many Õåtratropi -
áa| áãál onÕs ³oÓm fÓom autumn to spri ng. Ðnd
oááasi onal l y grow to typhoon-strÕngth l ÕvÕl s.
As shown i n µi g.5-l 7, thÕy arÕ áatÕgori zÕd
i nto thÕ fol l owi ng thrÕÕ pattÕrns basÕd on ori -
gi n and path:
East China Sea Lows
Japan Sea Lows
Twin Lows
; Bi rthpl Ðáe
, Paths of Iows
\
!" ã>
\
,\
'\tro
Citirta Si
!.i g.S-17 |rl l l hs Þt LÞrr's
106 ] A Gui de to shi p ÝÐnd|i ng
I
........
5.l MÕtÕorÞlogiáirI PhÕnÞmÕnÐ iß WÐters NÕighboÓißg Japtrn
EÐst Chi nÐ Sea Lows
ThÕ µast Áhina SÕa Lows originatÕ in thÕ µast Áhina SÕa or nÕar Âaiivan whÕn thÕ rigid wintÕr atmos-
phÕriá pattÕm of high prÕssurr in thÕ wÕst and lori'plÕssurÕ rn thÕ Õast abatÕs in thÕ sÕason from wintÕr
to Õarlã spring. BÕáausÕ a áontinrntal high ÕåtÕrrds to thÕ southÕast. a àrominÕnt trough is formÕd and
frontal wavÕ stimulatÕd. DuÕ to thÕ abor'Õ. thÕ lolr' dÕr.ÕlÞàs raàidlr and porr'ÕÓfully whilÕ proáeÕding
along thÕ southÕm áoast of thÕ JapanÕsÕ aráhipÕlaÕo' PÐßiáularh. tlrÕ lorrs srr'Õll signifiáantly aááompa-
niÕd by vÕry hÕar,ã sÕas as thÕy proáÕÕd northÕasn\-ard alÞng thÕ southÕÓn áoast of Japan at a spÕÕd
rangi ng 50 km/h to 80 km/h. µi g.5- 1l l shoæ s thÕ dÕr Õ1Þpi nÕnt sÕquÕnáÕ of an µast Áhi na SÕa Low.
ThÕ dÕvÕl opmÕnt of thÕ 1oæ. i s Õnorßl ol ts.
Fi g.S-18 µast Chi ßa SÕa LÞws
A Gæi de to Shi p HÐnd|i ng
Courtesy of Japan Meteorological Agenáy
E!fié MetÕorÞlÞgv fÞr SÐfÕ ³{avigatiÞn in µxtrÐtrÞpiáal and ÂrÞàiáÐl ÁyáiÞnes (StÞrms)
Japan Sea Lows
ThÕ Japan SÕa Lows originatÕ in thÕ samÕ sÕason and rrndÕr thÕ samÕ atmosphÕriá áonditions as thÕ µast
Áhina SÕa Lows, i.Õ. bÕtwÕÕn wintÕr and Õarly spring in áonditions of high prrssurÕ in thÕ wÕst and low
prrssurr in thÕ Õast. ThÕ Japan SÕa Lows will dÕvÕlop rapidly as prominÕnt troughs arÕ formÕd in thÕ Japan
SÕa whÕn the winter atrnosphÕriá prÕssrrre pattÕm abatÕs. SouthÕrly winds blow towards thÕ low and most
arÕas of Japan arÕ áovÕrÕd with warm air (Fig.S-l9). If a high is prÕsÕnt to thÕ south of thÕ JapanÕsÕ áoast,
afirrosphÕriá tÕrrrpÕraturÕ will risÕ, áausing Strong gusts with vÕry high sÕas. This phÕnomÕnon is known as
thÕ vÕmal storm. HowÕvÕæ thÕ supply of warm air is tÕmporary and tÕmpÕraturÕ drops abruàtly onáÕ thÕ
wintÕr atrnosphÕriá pattÕm aááompaniÕd by thÕ áold nor1h wind rÕfums in thÕ wakÕ of thÕ passing áold front.
áourtesy of Japan MeteoroIogiáal Agenáy
10B 1 A Gui de to shi à Ýand|i ng
I
Fi g.S-19 Japan SÕÐ LÞrvs
5.1
.:::
MÕtÕorologiáal PhÕnomÕna in WatÕÓs NÕighboling Japan
Twi n Lows
ThÕ Twin Lows appÕar in thÕ sÕason from NovÕmbÕr to Maráh' onr in thÕ north, and thÕ othÕr in thÕ
south ofthÕ JapanÕse aráhipÕlago (Fig.5-20). AftÕr proáÕÕdihg to thÕ Õast sidÕ by sidÕ, thÕy dÕvÕlop frè-
thÕr and arÕ joinÕd to onÕ low off thÕ Sanriku áoast. A Strong monsoon nÕarly ÕquivalÕnt to a typhoon
will follow behind this low aáÞompaniÕd Ì1'r.ery high sÕas.
Fig.5-20 Twin Lows
áourtesy of Japan ÜeteoroIogiáa| °genáy
A Guide to ship }|ÐndI.ng
Efi[@@ MÕtÕorolÞgy for SafÕ Navigation in µåtratroàiáÐl and TrÞpiáal CyálonÕs (Storms)
A. °nother |oW is generated
on the oÞc|uded front.
B. Another low is generated
topographiáalIy.
C. Âwo indeàÕndent lows are
proáeeding together.
Wi nter atmospheri á pressure áonfi gurati on
ThÕ typiáal wintÕr atmosphÕriá prÕssurÕ áonfiguration of high prÕssurÕ in thÕ wÕst and low prÕssurÕ in
thÕ Õast apprars fâom NovÕmbÕr to ¼aráh'
WhÕn a áontinÕntal high ÕxtÕnds to áovÕr Japan and a dÕvÕlopÕd low Õxists in thÕ northÕast arÕa offJa-
pan, thÕ wintÕr monsoon grows strongÕr and blows longÕÓ.
ThÕ wintÕr monsoon blows strong bÕáausÕ thÕ prÕssurÕ gradiÕnt bÕáomÕs sharpÕr whÕn thÕ high in thÕ
wÕst and thÕ low in thÕ Õast dÕvÕlop simultanÕously (Fig.5-21).
Courtesy of Japan MeteoroIogiáal Agency
1 10 A Gui de to Shi p Handl i ng
Fig.5.21 WintÕr atmÞspheriá pâessuâe áÞntiguratiÞn
5.1 MÕtÕoroiogiáal Phenomrna in WatÕrs NÕighboÓing Japan
High-wave zone (off Nojima Saki)
In thÕ sÕa µ}rÕa rast of Japan (off Noji-
ma Saki), marinÕ áasualtiÕs arÕ frrquÕnt
duÕ to high WavÕs áausÕd by thÕ wintÕr
monsoon, whiáh prÕvails in vast sÕa
arcaand áan last a long timÕ.
As thÕ sÞuthÕm tip of thÕ uppÕâ áold aiâ
passÕs ovÕr this sÕa arÕa (SÕÕ Fig.5-22.1,
thÕ fuäulÕnt air flow áarrsrd by áonvÕá-
tion áurrÕnts bÕáomÕs prÕdominant duÕ
tÞ thÕ largÕ diffÕrÕnáÕ in tÕmpÕrafurÕ
bÕtwÕÕn thÕ warm sÕa surfaáÞ in thÕ
Kuroshio CurrÕnt and thÕ áold air of thÕ
uppÕr laãÕr. This will furthrr inárÕasÕ
wave height.
As shown in Fig.5.23, this high-wavÕ
arÕa ÕxtÕnds ·0 to 37 dÕgreÕs north in
latitudÕ and 140 to 160 dÕgrÕÕs Õast in
longitudÕ. oááasionally, this high-wavÕ
arra apprars in thÕ southwÕst quadrant
at a áonsidÕrablÕ distanáÕ from thÕ áÕn-
tÕr of a low (Fig.5-24).
Âhis faát indiáatÕs that, to dÕtÕát a
high-wavÕ arÕa, thÕ movÕmÕnt of up-
pÕr-layÕr áold aiâ should bÕ áhÕákÕd on
thÕ isothÕrms of thÕ 500 hPa uppÕr-air
áhÐrt.
Fig.5.22 SouthÕrn ä of upper áold air
Fig.5-23 High-wavÕ zonÕ in the sea area east of Japan
Fig.5.24 High-wavÕ sÕátÞr in thÕ southwÕst quadrant of a low
A Gui de to shi p ÝÐndIi ng | 1.| 1
@¼ÕtÕÞrol ÞgãforSafÕNavi gati Þni nµåtratropi áal andTropi áal Cãál onÕs(Storms)
MÕtÕorolo giá al lnformation
WhÕn navigating undÕr thâÕat of a tropiáal dÕprÕssion or typhoon' a ship must áollÕÞt information from
mÕtÕÞrologiáal' organizations and thÕn utilizÕ thÕsÕ data. A rough mÕthod of dÕtÕáting thÕ árntÕr of a
stÞrm is known as Buys Ballot's Law: stand with your baák to thÕ wind; thÕ áÕntÕr of low prÕssurÕ will
bÕ from 15 to 30 dÕgrÕÕs for.ward from your lÕft hand (Fig.5-31) in thÕ NorthÕm hÕmisphÕrÕ, and on
your right hand in thÕ SouthÕrn hÕmisphÕrÕ. This law is alsÞ appliáablÕ to ÕxtratrÞpiáal áyálonÕs.
It is nÕáÕssary to knorÜ thÕ rÕlativÕ position ofthÕ ship to thÕ targÕt tropiáal dÕprÕssion or typhoon to
minimizÕ its ÕffÕáts. WhÕn a äphoon is moving northward and obsÕrvÕd wind dirÕátion on board áhan-
gÕs to áloákwisÕ, thÕ ship is in thÕ right-hand sÕmiáirálÕ. If thÕ wind dirÕátion áhanges to áountÕr-
áloákwisÕ, thÕ ship is in thÕ lÕft-hand sÕmiáirálÕ of a äphoon (Fig.5.25 and Fig.5-26).
Fig.5-25 Wind dirÕátion of typhoon (in thÕ forwa.álpart;
ThÕ ratÕ of áhangÕ in wind dirÕátion bÕáomÕs
greater whÕn thÕ distanáÕ bÕtwÕÕn thÕ ship and
thÕ áÕntrr of thÕ typhoon is smallÕr. ÁonvÕrsÕly,
its rate of change beáomÕs smailÕr whÕn thr dis-
tanáÕ bÕtwÕÕn thÕ ship and thÕ áÕntÕr of äphoon
grows largÕr. A iargÕ ratÕ of áhangÕ in wind dirÕá-
tiÞn also forÕtÕlls abrupt and drastiá dirÕátional
áhangÕ in wind dirÕátion (Fig.5.27).
With fÕw ÕxáÕptions, most ports and harbors
along thÕ southÕrn áoast of léan are ÕxposÕd tÞ
dangÕr duÕ to strong winds blowing towards thÕ
shorÕ whÕn a typhoon, dirÕáting northÕâly or
northÕastÕrly, is passing to thÕ wÕst of port.
Fig.5-26 ÁhangÕ Þf wind dirÕátion
112 A Guide to ship Ýand|ing
Fig.5.27 RÐtÕ of winál álirÕátiÞn áhangÕ
5.1
\r.'1.1;'... 1 ri çri...1 \l.rÓtrl r tT)l rhuotl:r
Avoiding Tropiáal Storms (TyphoÞns)
1. Dangerous and navi gabl e semi ci rÞl es
ÂhÕ right-hand sÕmiáirálÕ to thÕ path of a nphÞÞr-r (iaárng thÕ diÓÕátion torraâd rr'hiáh thÕ Óã-phoon is
moving) is known as thÕ dan-sÕrous sÕmiáirálÕ: hÕâÕ. u.ind speÕd iIrárÕasÕs bÕáartse lr-rnd direátion and
diâÕátion of typhoon movÕlnÕnt aIÕ thÕ satnÕ. and thÕ ship rnay bÕ bloæ.n toæ.ards thÕ áÕIltÕI of tliÕ Óy-
phoon (Fig.5-28). WhÕn a r-vphoon is loáatÕd in thÕ southÕrn oáÕan, at a distanáÕ from Japan. its stotm
arÕa has a áiráular form. As thÕ ßphoÞn approaáhÕs watÕrs nÕighboring Japan, thÕ stonn arÕa Õåpands
signifiáantly, and tÕnds to Õxpand prominÕntly in thÕ ÕastÕrn sÕmiáirálÕ. Strong winds and high wavÕs
arÕ formÕd in thÕ typhoon's southÕast quadrant.
Fig.5-30 shows that thÕ high-wavÕ arÕa prÕvails in thÕ southÕastÕrn qtradrant. ThÕ lÕft-hand sÕmiáirálÕ
tÞ thÕ path of a typhoon is áallÕd thÕ navigablÕ sÕmiáirálÕ bÕáausÕ wind dÕárÕasÕs duÕ to thÕ forward
motion of thÕ tãphoon (advÕrsÕ to wind dirÕátion), and thÕ wind blows thÕ ship away from thÕ ty-
phoon path (SÕÕ Fig.5-29). µven though it is áallÕd thÕ navigablÕ sÕmiáirálÕ, it nÕvÕrthÕlÕss aááompa-
niÕs thÕ Storm arÕa, and suffiáiÕnt áaÓÕ should bÕ takÕn.
an
F i g.5.29 NÐvi gl rbl Õ sÕl l l i ái Óál r
Âyphoon
Wind
Fig.5-31
Fig.5-30
oáÕan rl ar Õ
álrart Þf tyàhÞon
,arrd;\^
Buys Ballot Law
Northern Hemi sohere
A Gui de to shi p Ýand|i ní | l l ×
5'2 ArÞi di ng Âl.opi árl StÞÓm. tÂãàhÞol l.l
@MÕtÕÞrÞl ogyfÞrSÐfÕNavi gati oni nµåtratrÞpi áal andTrÞài áal Áyál ÞnÕs(StÞrms)
2. General ruIes for avoiding tropiáaI storms (typhoons)
ThÕ gÕnÕral rulÕs for avoiding tropiáal áyálonÕs or tãphoons arÕ 'summarizÕd as follows:
(As äphoons arÕ mainly disáussÕd in this áhapteæ thÕ following ru1Õs apply only to ships in thÕ NofthÕm hÕmisphÕrÕ.)
(a) If thÕ wind áhangÕs to áloákwisÕ, thÕ ship must bÕ in thÕ dangÕrous sÕmiáirálÕ. If possiblÕ, thÕ
ship should plaáÕ thÕ wind on thÕ starboard bow (45" rÕlativÕ), hold áoursÕ and makÕ as muáh
Way as possiblÕ to gÕt out ofthÕ dangÕrous zonÕ.
(b) If thÕ wind baáks thÕ ship, thÕ ship is in thÕ navigablÕ sÕmiáirálÕ. The ship should plaáÕ thÕ wind
on thÕ starboard quÐrter 1135" rÕlativÕ). hold áoursÕ and makÕ as muáh way as possiblÕ. (This
mÕthod of avoidanáÕ is áallÕd sáudding.)
(á) If thÕ wind rÕmains steady or nÕarly steady in tÕrms of dirÕátion, thÕ ship should bÕ in thÕ path of
thÕ äphoon, ahÕad of thÕ stotm'S árntrr. In this áasÕ, thÕ mastÕr should dÕáidÕ in advanáÕ whÕth-
Õr thÕ ship is ablÕ to rntrr thr navigablÕ arÕa ofthÕ typhoon safÕly or not. Ifthis aátion is dÕÕmÕd
praátiáablÕ, thÕ ship should plaáÕ thÕ wind 2 points on thÕ starboard quaftÕr (about 160. rÕlativÕ),
hold áoursÕ and makÕ as muáh Way as possiblÕ. When wÕll within thÕ navigablÕ srmiáirálÕ,
sáudding is rÕáommÕndÕd.
(d) If thÕ ship is in thÕ áÕntÕr, or nÕar thÕ cÕntÕr of thÕ tãphoon' thÕ ship should hÕavÕ-to with thÕ
wind on thÕ starboard bow.
Heave-to: When the Weather beáomes so violent in
the open sea that áontinued navigation Wi|| |ead to
diffiáu|ty or danger, the ship áan heave-to (i.e. lie with
the wind on the stÐrboard bow and run ahead at the
minimum possible speed for mÐintaining steerage
wÐy)' Âhe methÞd by whiáh engines are stopped and
the ship is allowed to drift is known as Iying-to.
F.ig.5-32 shows thÕ mÕthods for avoiding typhoons
in thÕ Nor1hÕm hÕmisphÕrÕ; alphabÕtiáal symbols
in thÕ figurÕ áotâÕspond with thosÕ abovÕ.
Fig.5-32 HÞw to Ðvoid tyàhoÞn
Today, thÕ ¼ÕtÕorologiáal AgÕnáy providÕs ships
with information on oáÕaniá mÕtÕorologiáal áonditions' Suáh as surfaáÕ wrathÕr áhar1s, uppÕr-air
áharts, oáÕan wavÕ áharts, photographs from wÕathÕr satÕllitÕs' and so on. A1l arÕ Õasy to obtain'
It should bÕ notÕd that muáh of thÕ data from on-board wÕathÕr obsÕrvations arÕ ináotporatÕd in thÕ
MÕtÕorologiáal AgÕnáy's WrathÕr rÕpofis. ThÕrÕforÕ, for thÕ pulposr of providing ships with moIÕ aá-
áuratÕ infotmation on oáÕaniá mÕtÕorologiáal áonditions, wÕathÕr obsÕrvations and rÕpÞrts will áontin-
uÕ to bÕ of vital impor1anÞÕ. SÕafarÕrs arÕ rÕquirÕd not only to dÕvÕlop thÕir mÕtÕorologiáal knowl-
ÕdgÕ' but also to sÕÕk to realrize safÕ ship opÕrations by making praátiáal usÕ ofthis knowledgÕ.
114 A Gui de to shi à ÝÐnd|i ng
*
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:
Is
a,"-
-: äg *1
'Ö
.,..is' .le',
a i,r:r *-.1.
'1ìs' ..!: :
!ftfisfit Handling Þf SpÕáial-PurposÕ Ships
Initial TurningAbility'Yarv.Cheáking and CoursÕ.KeÕpingAbilitiÕs 0f vÕry LargÕ Ships
In thÕ past, ship manÕuvÕrabiliä was ÕåprÕssÕd in tÕrms of results glÕanÕd from furning tests, suáh as
tactica| diamÕtÕr and advanáÕ' With thÕ dÕvÕlopmÕnt of largÕ-sizÕd ships with largÕ bloák áoÕffráiÕnts,
howÕvÕæ it has bÕÕn rÕáognizÕd that full SpÕátrum of manÕuvÕring áharaátÕristiás áannot bÕ ÕåprÕssÕd
by turning faátors alonÕ, but that othÕr faátors, suáh as initial turning ability and yaw-áhÕáking/
áoursÕ-kÕÕping abilitiÕs, should also bÕ takÕn into áonsidÕration. ThÕ above manÕuvÕring mÕasurÕs
wÕrÕ ÕxplainÕd in gÕnÕral in ChaptÕrl; thÕir praÞtiáal appliáation will bÕ ÕxplainÕd in this srátion.
A sáhÕmatiá diagâam of thÕ 10"/10" zigzag tÕst and rÕlatÕd faátors arÕ desáribÕd hµig.|-22, ChaptÕrl.
Initial fuming ability is rÕlatÕd to timÕ to sÕáond exÕáutr, tÐ; áoursÕ-kÕÕping ability to timÕ to áhÕák
yaw, ts; and yaw-ÞhÕáking and áoursÕ-kÕÕping abilitiÕs to ovÕrshoot anglÕs ar, and Ðz.
TablÕ Ñ-1 and Fig.6.4 - Fig.6-6 show thÕ áomparisÞns of 10./10. ztgzag tÕst for a 278'000-DWT
VLáC undÕr variÞus áonditions and for a áontainÕr ship in full-load áondition. In thÕ tablÕ, taátiáal
diamÕtÕr is shown as a multiplÕ of ship lÕngth, L.
Tabl e Ñ-1 RÕsul ts zi gzag l 0"/10. tÕst
'o1t}µfl"" 278,èx}DWâvL@Ì×20m(ls.zÚs) .E*â¡":3Ì
l+^ÙÐ Full load BaIlast FuII loÐd FuII load
llÕllIí H/d=oo ½Id=ä }Vd=1.5 ½ld=Þo
Âime to seáond
;;;Ù'Ù¡) 68
âime to áheák 1 15
yÐw, ts, (seá)
First overshoot.;ê.¡.;;Ðêê].) 14
TÐáticaI diÐmeter, Q ^
TD (multiple of L) e''
,f,
.':l:l l l l l::. ..'. .
r:]:]::i9il]t,,l
l:l:r:::l.i!:i::,.
'::::rrl rr,l r.::. rl
",,'ll2:8: :,
117
18it
12
4.5
,,!2,
. ']ll::':.iiliil,.
,::tt,.:l:.:'i::lLl:l:
-: r: ::413'..
6.1 ¼aneuvÕrability of vrry LargÕ Ships
800
(seá)
0 200 400 600 (secl
Fig.Ñ.4
Áompèison of 10"/10. zigzag tÕst betwÕÕn \|LÁÁ Ðnd ÁontainÕr shrp (full-load áÞndition)
FrÞm thÕ abovÕ tablÕ and figurÕs, it
is known that:
. VLÁCs have poor initial tuming
and áoursr-kÕÕping abilitiÕs, but
has good fuming ability' rÕlativÕ to
áontainÕr ships.
.TuÓning ability aÛd manÕuvÕÓing
abilitiÕs dÕtÕrioratÕ in fullload áon-
dition rÕlativÕ to ballast áondition.
. ManruvÕring abilitiÕs dÕtÕrioratÕ
in shallow watÕr áonditions (first
ovÕrshoot anglÕ ÕåáÕptÕd).
ThÕ áontÓol of a vÕry largÕ ship
will also bÕáomÕ inárÕasingly dif-
fiáult whÕn thÕ tèrning ratÕ has
bÕÕn fully dÕvÕlopÕd using a largÕ
amount of ruddÕr dÕflÕátiÞn. It is
important to áontrol thÕ ship's
turning ratÕ by putting ovÕr thÕ
ruddÕr gradually.
800
(seá)
s
-·0
10
0
S×o
10
0
-10
-×0
-50
P
s
- Headi ng angl e
- Rudder ang|Õ
0
Fig.Ñ.5
ÁomparisÞn of 10"/10" zigzag tÕst bÕtweÕn VLÁÁ in full-loÐd Ðnd in ballast áonditrons
Fig.Ñ.6
Áomparison Þf 10. l1,0. zigzag tÕst bÕtween in dÕÕp Waters and in shallow wateÓs
A Gui de to shi p ÝÐnd|i ng | 119
E[@@ HÐndling Þf SpÕáial-PrrrpÞsÕ SIlips
Nerv ÁoursÕ DistanáÕ and Collision AvÞidanáÕ Aátion
In rÕspeát to nÕw áoursÕ-kÕÕping maneuvÕring, áollision avoidanáÕ is sirnulatÕd undÕr
various áonditions for two full-loadÕd 280'000.DWÂ tÐnkÕrs making 15.7 knots and
mÕÕting on rÕáipÓoáal áoursÕs' Applãing rÕquisitÕ bridgÕ-to-bridgÕ distanáÕs, thÕ rÕ-
sults arÕ summarizÕd in thÕ following figurÕs:
.,-.t l
400
'ÄÄ
b
(m)
-400
-800
12¾ A Gui de to Shi p HÐnd|i ng
1.0 Nauti áaI mi |e (132 sÕá)
L
400 800 1 200
I
1 600
l ààÓtl aáh (Ál,,\)
280'000-DWâ Tankers
Speed't5.7 kts
H/d: oo
Fi g.6-7 KÕÕài ng onÕ shi 1l l áßcth tl i.ál ál sÕst àOi ¿t Ot
(m)
-800
(m)
400
As shown in Fig.6-8, sufifiáiÕnt áarÕ should bÕ taken for initial evasivÕ distanáÕ whÕn navigating in
shallow watÕrs, suáh as thÕ Malaááa Strait.
280'000.DWÂ Tankers
(m)
400
0
-400
.'| .8 Nauti áa| mi |es (214 seá)
t. _
I2o0 1600 2o0o -'-.)4¹'..*Í
Fig.Ñ.8 KÕeping onÕ ship length of álosÕst pÞint of apprÞaáh (CÀA) with hard ovÕr hÕlm by own ship
1.6 Nauti áal mi l es (186 seá)
Speed 15.7 kts
H/d: 1.5
2..| NautiÞalmiles (318 seá)
A Guide to shiÓ ÝandIins | .|2.1
!ft[s@ Handling of Sàeáial-PurposÕ Ships
Fig.6-9 shows a simulatÕd rÕsult whÕn passing Õaáh othÕr by kÕÕping onÕ nautiáal milÕ of álosÕst point
o³apàroaáh i n opÕn sÕÐ.
µaáh ÕvasivÕ áoursÕ-áhanging anglÕ has áhangÕd to 20" to starboard with using 10. ruddÕr to starboard
whi IÕ áontÓol l i ng thÕ fuÓni ng ratÕ.
µaáh should takÕ thÕ initial evasivÕ aátion at thÕ bridgÕ-to-bridgÕ distanáÕ of 3.8 nautiáal milÕs.
(m)
1 000
0
,1 000
-2000t:.
Fig.6.9 KÕÕping one nautiáal mile of ÁPA eaáh taking ÕvasivÕ áoursÕ-áhanging anglÕ Þf 20 degrÕes
280'000-DWâ ÂÐnkers
Speed 15.7 kts
H/d: oo
6.1 ManÕuvÕÓability of VÕrã LargÕ Ships
SpÕÕd Control
Assuming that a ship is approaáhing its bÕrth using a dÕáÕlÕration manÕuvÕr' spÕÕd and distanáÕ áov-
ÕrÕd arÕ dÕsáribÕd in Fig.6.10 aftÕr thÕ main ÕnginÕ has bÕÕn stoppÕd and thÕ ship is making 6 knots.
ApproximatÕ distanáÕ áovÕrÕd by thÕ time ship spÕed is rÕduáÕd to 2.5 knots, thÕ áritiáal speed at
whiáh ruddÕr ÕffÕátivÕnÕss is nÕarly lost, (Kt)
áan bÕ obtainÕd from thÕ diagram (2,800 m 5 6
for a l60,000-ton tankÕr; and 4,000 m for a } s
280,000-ton tankÕr). -·- o
TimÕ rÕquirÕd for spÕÕd rÕduátion is also ±
shown as a funátion of displaáÕd wÕight and ^ :
distanáÕ run. (For ÕxamplÕ, a 160'000-to" ,')
tankÕr rÕquires approximate|ã 22 minutÕs
for its spÕÕd to dÕáÕlÕratÕ tÞ 2.5 knots; '
whilÕ a 280,000-ton tankÕr takÕs approxi- 0
matÕlv 30 minutÕs.)
)laáement - 280'000ton
'** 160,000ton-
- 90.000ton
t
\.
>
\ -<\
å a
rl n
T0mi n-'
i omi n.''
I
1000 ' 20i00 3000 4000
DistanÞe run (m)
Fig.Ñ-10 DÕáÕlÕrationdiagram
In aááordanáÕ with thÕ Standards for SafÕæ-\IanagÕmÕnt SystÕm (sMS), thÕ following prÕáautions arÕ
rÕquirÕd during dÕáÕlÕration manÕuvÕrs æ'hÕn a ship is approaáhing a bÕrth in harbor or an anáhoragÕ
outsidÕ a harbor:
. Ship spÕÕd should bÕ rÕduáÕd gâaduallã. adjusting to thÕ rÕmaining distanáÕ.
. Ship should not ovÕrshoot thÕ targÕt dÕstination.
. Ship should bÕ brought to a stop rr-ith dirÕátional áontrol bÕing kÕpt stablÕ.
It should bÕ notÕd that hÕadway and dirÕátional áonffol arÕ diffiáult to maintain drèing suáh manÕuv.
ers, a áondition ÕxaáÕrbatÕd by poor stÕÕÓing ability at low spÕÕd. ThÕ spÕÕd reduátion sáhÕmÕ shown
in Fig.3-34 in Chapter 3 may provÕ hÕlpful whÕn it áomÕs dÕÞÕlÕration manÕuvÕrs.
ThÕ movrmÕnt of vÕry largÕ ships áannot bÕ áontrollÕd using áonvÕntional ship-handling tÕáhniquÕs
a1onÕ. As suáh, attÕntion should bÕ paid to maintaining dirÕátional áontrol using vÕrifiÕd numeriáal
data and rÕadings from a yaw ratÕ mÕtÕr.
VÕry largÕ ships arÕ characteized as .,good tuming ability, but ÕåtrÕmÕly poor áoursÕ-kÕÕping and ini-
tial turning abilitiÕs.''
It is hopÕd that you kÕÕp safÕ ship handling in mind, firmly grasping the abovÕ-mÕntionrd manÕuvÕr-
ing áharaátÕristiás ofvÕry largÕ ships.
A Guide to shiÓ Ýandlins | 123
!ft!s@ Handling Þf SpÕáial-Purpose Shiàs
IntroduátiÞn
Suáh ships, typi³rÕd by PurÕ Car CarriÕrs or Car-fÕrriÕs, arÕ áharaátÕrizÕd as a spÕáial dÕsign áharaátÕr-
izedbã a high frÕÕboard, with a signifiáant arÕa of thÕ hull and supÕrstruáturÕ abovÕ watÕr as comparÕd
to thÕ undÕrwatÕr hull.
This mÕans that wind has a signifiáant impaát on thÕ hull and that thÕ bow wavÕ has a muáh grratrr Õf-
fÕát on thÕ largÕ flarÕd bow.
Partiáular attÕntion shÞuld bÕ paid to typhoons or approaáhing low fronts, as thÕy áan rÕsult in loss of
manÕuverability duÕ to thÕ ship bÕing buffÕtÕd by strong winds and wavÕs; dÕtÕrioration of ruddÕr Õf-
fÕátivÕnÕss as thÕ rÕsult ofheavy rolling and pitáhing; and grÕatly rÕduáÕd spÕÕd áausÕd by prÞpÕllÕr
raáing, whiáh in furn may make it diffiáult to maintain áontrol ovÕr thÕ main ÕnginÕ. ThÕsÕ vÕssÕls arÕ
alsÞ susáÕptiblÕ to anáhor dragging duÕ to strong winds.
ÂhÕrÕforÕ, it is important to grasp wind ÕffÕáts and undÕrstand the manÕuvÕrability limits thÕy imposÕ.
124 i ^ Guido to Ship }|andlißg
I
Hull StructureProperties of PCCs
Âo maåimize vÕhiálÕ-áarrying capacitã,
Ð PÁÁ is dÕsignÕd as a rÕátangu|ar-tãpe
hull struáturÕ With high fl.ÕÕboard' with
an ÕnoÓInous area of hull and supÕÓ-
structurÕ abovÕ watÕr as áomparÕd to
the undelwater hull. SináÕ thÕ PÁÁ hull
form is distinát from thosÕ of tankÕÓs
and áontainÕr ships, PÁÁs arÕ allvays
vulnÕrablÕ to thÕ ÕffÕáts of rr,ind, rÕ.
gardl Õss of thÕi r l oad áondi ti on.
Pri nái pal parti ául aÓs of thÕ PÁÁ arÕ
shown i n ÂÐl rl Õ 6-2.
Length over all (LOA)
BreÐdth extreme (B)
Depth moufded (D)
Summer draft
Draft Designed draft
BallÐst áondition
Anáhor Weight (AC14 type)
Weight
Gable
Length
190m
32.26m
37'41m (áÐrgo deck top)
14325m
8.325m
7.50m
8'·25 kg
143.7 kglm
687.5m (l 2l 13 shaákl es)
Tab|Õ 6-2 PÓi nái àl rl pÐÓti áLtl ÐÓs Þ1'thá rrrÞtl Õ] PÁÁ (6.l ()()-uni t ál l à;l ái 11')
Typiáal symbols, suáh as Aa and Ba arÕ dÕfinÕd as shown in Fig.6-l l.
As shown in µig.6.l l ' thÕ projÕátion of a full-sizÕd PÁÁ's midship abovÕ-watÕr sÕátion has an approxi-
matÕ valuÕ ranging from 950 m2 to 1,050 m2.thÕ valuÕ for thÕ latÕral planÕ of symmÕtry rangÕs from
5,500 mu to 6,200 m2.
5,500-6,200m2
I
.. .... ..]. .AÇ:
BaÒ
. ....
AaÒ l of äoßïíqffir eoÉç om çftdäm é
Projeátion of underwater portion on midship
µi g.6-11 FÓotrt Ðnál si ál á pÓtl j Õáti otl s ol.abor,'Õ-rvatáÓ Ðl l d tttrdáÓwl ttÕt. 1l oÓti Þns oI.ÀÁÁ--s
A Gui de to shi p ÝÐnd|i ng | 12]
!ftfl@ftt Handling of SpÕáiÐl-PurposÕ Ships
TablÕ 6-3 áomparÕs a PÁÁ, a áontainÕr ship and a tankÕr, Õaáh in loadÕd áondition. ThÕ ratio of thÕ
front projÕátion of thÕ abovÕ-watÕr portion, Aa, is áomparÕd to that of thÕ undÕrwatÕr portion, Aw, and
thÕ ratio of sidÕ projÕátion of thÕ abovÕ-watÕr portion, Ba, to that of thÕ undÕrwatÕr portion, Bw. ÂhÕ
wi nd ÕffÕÞt on a PÁÁ i s about 1.2 ti mes (×.|12.6= 1.2) on thÕ front vi Õw and l.5 ti mÕs (2'9l |.9=|'5)
on thÕ sidÕ viÕw as áomparÕd to a áontainÕr ship. ThÕ tablÕ also indiáatÕs that thÕ wind ÕffÕát on thÕ
PÁÁ is aÌo:uj 2.6 timÕs on thÕ
ttont vi Õw and 3.6 ti mÕs
on thÕ Shi p Item
sidÕ viÕw as áomparÕd to a PCC (6,400-unit áapaáity)
tankÕr. So, a PCÁ is highly
susáÕptiblÕ to thÕ ÕffÕáts of áontÐiner ship (6'000-TµU)
wind. Tanker (2×0'000-DWâ)
Thble Ñ-3 PâincipÐl partiáulars of thÕ ModÕl PCC (6'400-unit áapaárty,;
Wind µffÕáts on PÁÁ whilÕ Underway
.|. Wind foráe (Resultant wind foráe) on PCC
ThÕ wind foráÕ aáting on Õaáh portion of thÕ hull diffÕrs aááording to thÕ shapÕ of thÕ hull and thÕ rÕla-
tivÕ wind dirÕátion. HowÕvÕæ ship opÕrators dÕal with Õaáh loáal wind foráÕ as an intÕgratÕd valuÕ. This
unifiÕd foráÕ is tÕrmÕd thÕ rÕsultant wind foráÕ aáting on thÕ working point. ThÕ rÕsultant wind foráÕ
aáting on thÕ hull is áaláulatÕd by thÕ formula dÕvised by G. HughÕs as shown in F.ig.Ñ-12. ca in this
Õquation is thÕ rÕsultant wind foráÕ áoÕfftáiÕnt, its valuÕs varying with thÕ rÕlativÕ wind dirÕátion off
bow. ThÕ áurvÕ obtainÕd by plotting thÕsÕ valuÕs shows thÕ samÕ trÕnd dÕpÕnding on thÕ äpÕ of ship.
Simplified formula of wind resultant foráe (F)
F = 112' P ' ca. V2 (Aa . áos2 0 +Ba. si n2 0)
p : Speáifiá density of air (0.125)
Ca: Resu|tant wind foráe áoeffiáient
a : DistÐnáe of the áenter of wind foráe from bow (m)
C : Center of the wind foráe
Aa & Ba: Projeátion of above-water portion (m,)
Fig.6-12 SimplifiÕd foÓmula Þf wind rÕsultant fÞráÕ and rÕiatÕd ÕlÕmÕnts
Front ratio (AÐ/Aw) Side ratio (BalBw)
...... ×.1 2.9,,...-.,,,
2.6 1.9
,. 1.2,', "r ,. 0.8
{*
:rl l i rr.r.l
ti
:ä
.Ä
126 A Gui de to Shi p HÐndl i ng
6.2 ManeuvÕraÌilitã ol ÀurÕ Car CarriÕrs (PÁCs) _Wind µffÕáts
ÂhÕ rÕsultant wind foráÕ ÞoÕffiáirnt of PÁÁs áan roughly bÕ obtainÕd from Fig.Ñ-13. ThÕ working
point of wind foráÕ' loáatÕd at a distanáÕ of a from thÕ forÕ pÕrpÕndiáular (FP), movÕs with the wind
dirÕátion. WhÕn thÕ rÕlativÕ wind dirÕátion is nÕar thÕ dirÕátion of thÕ bow, thÕ woÓking point is at thÕ
position nÕar thÕ bow, moving abaft as thÕ anglÕs of rÕlativÕ wind dirÕátion offbow inárÕasÕ.
2.0
1.5
1.0
0.5
0.0
Wi nd di reÞti on (d)
Fig.6-13 RÕsultant wind foráÕ áoÕffiáiÕnt (Ca) of PÁCs
ThÕ rÕsultant wind foráÕ aáting on thÕ working point variÕs with wind spÕÕd and dirÕátion, rÕaáhing a
maximum whÕn thÕ bÕam wind is aáting on thÕ largÕst wind-affÕátÕd arÕa. In thÕ áasÕ of thÕ modÕl
PÁÁ, as shown in Fig.6-14, it áan rÕaáh 290 tons undÕr a wind spÕÕd of 25 m]s and a rÕlativÕ wind di-
rÕátion of90 dÕsrÕÕs.
400
·00
200
100
0
Re|ative Wind direátion
Fig.Ñ.14 RÕsultant wind foráÕ vs. wind speed and relative wind dirÕátion
Ñ
O
Ä
µ
o
()
á)
()
o
á
=
Ä
=
í
Ä
µ
á
o
á)
L
o
Þ
á
.;
á
Ä
=
í
Ä
Ä
E
A Gui de to shi p ÝÐndl i ng 12
!ft!@ftt Handling of SpÕáial-PurposÕ Ships
2. Leeway Ðnd áheck helm for mÐintaining straight áourse
WhÕn thÕ wind bÕgins to blow from thÕ starboard bow whilÕ undÕrway, tèrning momÕnt to pÞrt is ÕxÕr-
tÕd duÕ to thÕ rÕsultant wind foráÕ on thÕ working point. HowÕvÕr, whÕn thÕ wind shifts its dirÕátion
abaft the bÕam, turning momÕnt to starboard is
ÕxÕrtÕd duÕ to thÕ baákward shift of thÕ work-
ing point (Fig.6-r5). WhÕn thÕ wind from thÕ
starboard bow áontinuÕs blowing on thÕ ship
underway, its bow is swÕpt away downwind by
thÕ tuÓning momrnt to port. DuÕ to thÕ drifting
of thÕ hull to lrÕward, thÕ flæid foráÕ from thÕ
pÞr1 bow on thÕ undÕrwatÕr hull áausÕs thÕ
tuming momÕnt to starboard. If thÕ working
point of wind foráÕ is loáatÕd abaft that of fluid
fÞráÕ' thÕ ship's bow tÕnds to turn into thÕ wind.
LÕÕway is dÕfinÕd as thÕ anglÕ (f.) bÕtwÕen
thÕ linÕ of thÕ ship's apparent Þoursr (thÕ bow
hÕading) and thÕ linÕ that thÕ ship aátually
makÕs good through thÕ watÕr (Fig.6-1Ñ).
WhÕn navigating a width-áonfinÕd áhannÕl
undÕr thÕ influÕnáÕ of wind and tidal áurrÕnt,
prudÕnt ship handling is rÕquirÕd in áonsidÕra-
tion of lÕÕway. For this purposÕ' thÕ ship is rÕ-
quirÕd to takÕ a littlÕ morÕ windward áoursÕ
than thÕ plannÕd Þourse in ordÕr that thÕ ship's
áÕntÕr of thÕ gravity may rÕmain on thÕ plan-
nÕd áoursÕ linÕ.
LÕÕway will inárÕasÕ, as thÕ wind spÕÕd grows
strongÕr or thÕ ship is making lÕss spÕÕd.
In this áasÕ, ship handling is requirÕd to adjust
lÕÕway by áhÕáking thÕ ship's position frÕ-
quÕntly. HowÕvÕÓ. whÕn navigating a naÓÓÞw
áhaèÕl' thÕ ruddÕr anglÕ to bÕ dÕflÕáted is
limitÕd to 15 dÕgrÕÕs against thÕ ship's maåi-
mum ruddÕr anglÕ of 35 dÕgrÕÕs. Around 20
dÕgrÕÕs of ruddÕr anglÕ must bÕ rÕsÕrvÕd for
safÕty rÕasons.
-+ Ship,s heading
* ship," p.th
Í F|uidforáe
f Wind foráe
O Center of fluid force
o center of wind foráe
ä Center of gravity
W
Win*
âuring moment
by wind
Turing moment
by wind
>=-
W!èrj
Fig.6.15 Turning momÕnt by wind
128 ' A Gu.de to Shi p HÐndIi ng
I
Fig.Ñ-16 DÕfinition Þf lÕÕway, ´.
6.2 ManÕuvÕrability of PurÕ Áar Carâiers Õáá,l _Øno ÒrÓ...,
Ä
3
Ä
o)
-J
3. Gontrollability limits of PGC in wind
When thÕ wind speÕd is inárÕasing or thÕ ship is making lÕss speÕd on thÕ bÕam wind, thÕ outáomÕ of thÕ
magnitudÕ of lÕÕway with ruddÕr hÕld amidsËps is shown in Fig.6-u. FÞr ÕåamplÕ, whÕn a wind of 15 m/s
is blowing and thÕ ship is making 12 knots, lÕÕway will appÓoximatÕly bÕ 7 dÕgâÕÕs, but whÕn thÕ ship
spord dÕárÕasÕs to 8 knÞts' lÕÕway inárÕasÕs to 1 5 dÕgÓÕÕs.
30"
25"
20"
15"
10"
7"
50
0"
Ship speed (knot)
Fig.6-|7 LÕÕway as funátions of wind and ship spÕÕd (bÕam wind; rudder held amidships)
TablÕ 6-4 shows thÕ amount of áhÕák hÕlm rÕquirÕd to maintain a straight áoursÕ. ThÕ ship will losÕ its
áontrollability on a bÕam wind of 10 m/s with a ship spÕÕd of 4 knots. WhÕn making 6 knots, thÕ ship is
áontrollablÕ undÕr thÕ samÕ wind áondition, but thÕ rÕquirÕd ruddÕr dÕflÕátions of áhÕák hÕlm áan rÕaáh
21 dÕgrÕÕs.
Ship speed (kts)
Wid speed (m/seá)
r0
15
20
25
Ù
oo: Rudder ang|e > 35 deg. (It means beyond áontrol) ¶ Under áontroI l Beyond áontroI
ThblÕ 6-4 RÕquiâÕd áhÕák hÕlm for kÕÕping straight áoursÕ
A Guide to ship ÝandIins | 129
!frfi!@ Handling of SpÕáial-PurpÞsÕ Ships
Fig.Ñ.l8 (a) and Fig.Ñ-l8 (b) show thÕ áontrollability limits of a PÁÁ in strong wind áonditiÞns. In thÕ
figurÕs, thÕ ruddÕr dÕflÕátions of áhÕák hÕlm rÕquirÕd to kÕÕp a straight áoursÕ arÕ shown as funátions
of wind dirÕátion, and thÕ wind spÕÕd Va tÞ ship spÕÕd Vs ratio,.i.Õ. ValVs, from onÕ to fivÕ.
Fig.6-18 (a) shows thÕ áontrollability limit whÕn thÕ maximum ruddÕr dÕflÕátion is set to 35 dÕgrÕÕs'
ThÕ ship will bÕ unáontrollablÕ in thÕ rÕgion from 70 to 160 dÕgrÕÕs whÕrÕ thÕ Va tÞ Vs ratio is 5, and
from 100 dÕgrÕÕs to 135 dÕgrÕÕs whÕrÕ thÕ Va tÞ Vs ratio is 4. In áasÕ of a 15-dÕgrÕÕ limitation on
maximum ruddÕr dÕflÕátion, as shown in Fig.6-18 (b), thÕ rÕgion of áontrollability bÕáomÕs muáh nar-
rowÕr than in thÕ áasÕ of a 35-dÕgrÕÕ limitation. For ÕxamplÕ' whÕn thÕ ship is making 10 knots undÕr
a wind of 30 knots, i.Õ. thÕ Va to Vs ratio is 3, thÕ ship will bÕ unáontrollablÕ in thÕ rÕgion from 75 dÕ-
grrÕs to 150 dÕgrÕÕs offbow in áasÕ of a 15-dÕgrÕÕ limitation on maximum ruddÕr dÕflÕátion.
(i) Maåimrrm ruddÕr dÕflÕátion
35 dÕgrÕÕs
Va: Wind speed
Vs: Ship speed
Unáontro||abIe region
áontro||abIe region
with 35-degree
rudder angle
30"
E
Ñ
-á
å
()
o
-á
60"
50"
40"
·5"
30"
20"
10"
0"
ij;;.l \.tg :::¡
60" 90" 120" 1 50" 190'
Wi nd di reáti on
0
60"
50'
40"
30'
20"
l í
10"
Þ
_wi th 1S-degree
rudder angle
µ
Ñ
-á
-Y
(J
á)
-á
()
(b) MÐximum ru<lálÕr álÕflÕátion
15 degrÕÕs
0"
0 30" 60'90" 120' 150" l g0"
Wi nd di reáti on
µig.6-18 RÕquirÕd áhÕák hÕ1m tÞ kÕÕp straight áoulsÕ as funátions of wind diâeátion ant1 wind spÕÕd rÐtio 1vÐ/vs;
ValVs
=3
Val V
A*r*J=l
:\
1×0 A Gui de to shi p ÝÐnd|i ng
l
6.2 ¼anÕuvÕrability Þf PurÕ Car CarriÕrs (PCCs) _Wind µffÕáts
Fig.6-19 shows thÕ áontrÞllability limits of various ship typÕs whÕn thÕ maximum ruddÕr dÕflÕátion is
limitÕd to 30 degâÕes. As wÕ áan sÕÕ, the PCC has a narrowÕr rÕgion of áontâollabiliä than othÕr äpÕs
of ship. For ÕxamplÕ, thÕ áritiáal whd spÕÕd on a tÐnkÕr in ballast áondition is 5.0 timÕs as muáh as
ship spÕÕd' whilÕ that on a PCÁ is approximate|ã ·.6 timÕs as muáh as ship spÕÕd.
6
5,0-...'×
10
E
o)
Ä
o-
Ä
.g
-á
áÛ
Þ
Ä
á)
o-
ál)
E
C
=
U'
Ñ
4
·.6
2
0
Controllable region
30"60'90" 120"1 50"
1 90"
Relative wind direátion
_ vlác (23o'00o-Dwâ) bÐl|ast
- áontÐiner ship (1'8o0-TµÆ
- Àáá {6'40Þ-Unit áÐàÐáity)
Fig.6.19 Controllabiliæ' limits of r ÐÓiÞus t\ pÕs of ship (30-dÕgrÕÕ ruddÕr dÕfleátron)
4. MÐneuvering assistanáe for PCc
WhÕn thÕ ship is swÕpt away downwind by strÞng wind, a bow thrustÕr may bÕ usÕd for hull áontrol. In
suáh a áasÕ, it should bÕ notÕd that thÕ pÕrmissiblÕ maximum ship spÕÕd is limitÕd to about 4 knots or
lÕss. ¼orÕovÕæ undÕr strong wind áonditions whÕre manÕuvÕrability is rÕstriátÕd in a harbor Þr fair-
way, assistanÞÕ by tugs shouldbÕ takÕn into áonsidÕration.
A Gui de to Shi p Handl i ng I I i
I
I
I
![![@ftt l{andling of Speáial-PurposÕ Ships
5. Âurning of PcC under strong wind
With tuming in áalm áonditions as rÕfÕrÕnáÕ, thÕ turning of a PCC is invÕstigatÕd whÕn thÕ wind inárÕa.
sÕs spÕÕd to 2, · and 4 timÕs as muáh as initial ship spÕÕd. µaáh initial speÕd is sÕt as 11.6 knots (6 m/s).
F'ig6-20 shows thÕ fuming traáks, ináluding thÕ furning traák in áalm áonditions, undÕr thÕ abovÕ wind
spÕÕd áonditions whÕn thÕ wind is blowing 0o, 90", |8o", 2,7o" from thÕ approaáh áoursr.
&&x××Ö8**&*r×s
1200 -- ..
1000
i 1
i - i
ri
4A)
14Ä 'i I
s
_200 _
400
1 :. -r +
Ji ri
i::i
i -r i-l'
2N " --","----
Va:Wind speed
Vs: Ship speed
=11.6kts (6 m/seá)
_ áalm áondition
* ValVs:2
- ValVs:3
- ValVs:4
Va:tlÃind speed
Vs:Ship speed
=11.6|rts (Òmlsec)
- áatm áondition
- Va/Vs:2
- Valvs:3
* Va/Vs:4 '
A Gui de to Shi p Handl i ng
6'2 ManÕuvÕrabilitã of PurÕ CaÓ CÐrriÕrs (PCCs) _Wind EffÕáts
As shown in thÕsÕ figurÕs, furning abiliä of a ÀCC is geat|Ã influÕnáÕd by wind. As thÕ Va to Vs ratio
rraáhrs 4, thÕ ship áan entÕr an unáontrollablÕ rÕgion dÕpÕnding on rÕlativÕ Ùnd diâÕátion, and somÕ
PCCs havÕ ÕxtrÕmÕ diffiáultiÕs for ÕxÕáuting turning manÕuvers. Due to thÕ uniquÕ manÕuvrring áhÐr-
aátÕristiás of the PCC as mÕntionÕd in this subsÕátion, it is rÕquÕstÕd that PCCs bÕ opÕratÕd safÕly by
taking maneuvÕrability limits into áonsidÕration.
.2ä
-4Ä
-è
-1è
-12Ä
-1400
Va:Wind speed
Vs:Ship 6àed
=11.6kts (6 m/seá)
- 6i1ln áondition
- ValVs:2
E va/vs.3
- Va/Vs:4
(m)
1è'-''
è
t
l
l
I
I
.1....-.,
l
1ffi
èn
12ä
lä0
l l
-.1.
Va:Wind speed
Vs;Ship speed
=11.6kts (Þm/seá)
_ calm áondition
-Va/Vs:2
- Va/Vs:3
_ VÐlVs:4
Fig.Ñ.20 Tuming of PCC undÕr strong wind
A Guido to ship ÝÐndling | 1:
!ft!fis Handling of SpÕáial.PurposÕ Shiàs
Wind µffÕáts on Páá at Anáhor
.t. Introduáti on
Anáhoring has alrÕady bÕÕn disáussÕd in SÕátion 3.l. This sÕátion will prÕsÕnt
áonÞrÕtÕ ÕxamplÕs of thÕ safÕ anáhoring of wind-pronÕ PCCs. A ship at anáhor im-
paátÕd by thÕ wind will pÕriodiáally swing around thÕ anáhorÕd position. HowÕvÕæ
as thÕ ÕxtÕrâtal foráÕs ÕxÕr1Õd by thÕ wind and/or tidal strÕam inárÕase' thÕ risk of
dragging anáhor risÕs. A PCÁ at anáhor is in grÕat dangÕr of dragging anÞhor duÕ to
its vÕry largÕ wind-affÕátÕd arÕa. SuffiáiÕnt áarÕ should bÕ takÕn to avoid suáh an ÕvÕnt.
2. Ho|di ng power of anchor and áabl e
ThÕ anáhoring systrm and holding powrr of a ship riding tÞ a singlÕ anÞhor arÕ shown in Fig.3-8
in SÕátion 3.1. ThÕ holding powÕr áoÕffiáiÕnts Þf anáhors (ia) arÕ gÕnÕrally takÕn as 3.5 for thÕ
JIS tãpÕ, and,7.0 for thÕ °Á|4 tãpe. HowÕvÕr, ÕxpÕrimÕnts show that thÕ áoÕffiáiÕnt of thÕ AC14
typÕ anáhor may dÕárÕasÕ its valuÕ bÕtwÕÕn 2 and ·, dÕpÕnding on sÕabÕd áonditions, ÕspÕáially a
sÕabÕd typifiÕd by thÕ prÕSÕnáÕ of sÕdimÕntary slimÕ. CarÕ should bÕ takÕn to adjust to dÕtÕriora-
tion of thÕ holding áoÕffiáiÕnt. ThÕ friátional áÞÕf³ráiÕnt of thÕ áablÕ is normally takÕn as 0.6.
Aááording to thÕ prináipal partiáulars of thÕ modÕl PÁÁ in TablÕ 6-2, thÕ holding powÕr of thÕ AÁ
\4 Iãpe anáhor i s Õsti matÕd at about 58 tons, (l a.Wa _,7.0x8,·25+58.l 0× kg) and thÕ áabl Õ,s
holding powÕr is ÕxpÕátÕd to bÕ about 12 tons whÕn thÕ laid down part (holding par1) of thÕ áablÕ is
5 shaákl Õs (,l á.wá.l :0.6å|4·..7å2,7.5x5 Ç tzxt0× t<g).
3. Length of áab|e to be paid out Ðnd áatenary
¼aximum anáhor-holding powÕr âÕquirÕs a suffiáiÕnt lÕngth of áablÕ bÕ paid out tÞ prÕvÕnt thÕ anáhor
frÞm bÕing pullÕd upward by horizontal ÕxtÕrnal foráÕ. ThÕ lÕngth of thÕ áablÕ forâning a caIenary
should bÕ Õqual to that of thÕ paid out áablÕ, i'Õ. a minimum nÕáÕssary lÕngth of áablÕ to bÕ paid out
(Fig.6-2r). µxáÕss paid out áablÕ is laid down and sÕrvÕs as a hÞlding part Þf thÕ áablÕ (sÕÕ Fig.3-8).
Assuming Õquilibrium bÕtwÕÕn thÕ horizontal Õxtemal foráÕ on thÕ ship and thÕ holding powÕr Þf thÕ
anÞhor (Fig.6-21), Fig.6-22 shows thÕ rÕlationship bÕtwÕÕn thÕ lÕngth of áablÕ to bÕ paid out as a áat-
Õnary and thÕ dÕpth of watÕr. For ÕxamplÕ, assuming that thÕ holding powÕr of thÕ ship's anáhor is
ÕquivalÕnt to a 60-ton anáhoæ and watÕr dÕpth for anáhoring is 30 m, thÕ lÕngth of thÕ áablÕ to bÕ paid
out is morÕ than 190 m (about 7 shaáklÕs).
::::::
6.2 ¼aneuvÕrability of ÀurÕ Car ÁarâiÕÓs (PCCs) -Wind µffÕáts
=.=.:.=:|:..:':-=:7i:i::'.:..:l:Z1'v:'-7...4/'jj.:11.1j=i:.:.:..::f 250
Fig.6-21 µquilibrium áondition brtwÕÕn ÕxtÕrnal fÞráÕ
and anáhor-hoiding power
10 20 ·0 40 50
Depth of water (m)
Fig.6-22 WatÕr dÕpth and lÕngth of áablÕ to be paid out
4. Ship's swing motion at anáhor
Ship's swing motion at anáhor and impulsÕ foráÕ wÕrÕ ÕxplainÕd togÕthÕr with a figurÕ in SÕátion 3.l'
Anáhorins.
5' Danger of draggi ng anáhor
DuÕ to impulsÕ foráÕ and'/or SubsÕquÕnt strong wind strÕss' thÕ ship may bÕ at risk of dragging anáhor.
ThÕ dangÕr of dragging anáhor for a PCC riding tÞ a singlÕ anáhor is invÕstigatÕd for a ship ÕquippÕd
with thÕ anáhor offÕring 50 tons of holding powÕr. In thÕ áasÕ whÕrÕ áablÕ tÕnsion rÕaáhÕs its maåtmum
limit duÕ to swing motion, thÕ impulsÕ foráÕ on thÕ áablÕ Þan bÕ ÕstimatÕd by multiplying thÕ wind
forÞÕ on thÕ front viÕw by thÕ swing áoeffiáiÕnt, n. ThÕ valuÕs for swing áoÕffiáiÕnt, n, arÕ takÕn as 5
for PCCs, and bÕtwÕÕn 2.5 and 3.5 for othÕr ships. GivÕn an average wind spÕÕd of 13 m/s, áritiáal and
thÕ maåimum wind spÕÕds will statistiáally bÕ about |6.2 rn]s and 18.2 m,/s' rÕspÕátivÕly. Caláulations
indiáatÕ that thÕ front viÕw of a PCC will suffÕr a wind foráÕ of 9.8 tons. If thÕ swing áoÕfftáiÕnt is
takÕn as 5, a maximum tÕnsion of 49 tons (5x9.8) will bÕ ÕåÕÓtÕd on thÕ áablÕ. UndÕr thÕsÕ áonditions,
an anáhÞr with 50-ton hÞlding powÕr wi1l bÕ r,ulnÕrablÕ to dragging. Aááordingly, whÕn a PCÁ is riding
to a singlÕ anáhor of 50-ton holding powÕr, prÕáautionary mÕasurÕs should bÕ takÕn to prrvrnt anáhor
dragging áasÕ whÕn avÕragÕ and maximum wind spÕÕds rÕaáh approximatÕly 13 m/s and 18 m/s.
TablÕ 6-5 shows avÕragÕ and maximum wind
spÕÕds that áan lÕad to anáhor dragging (áatÕ- Swißg coeffáient o* ¡}g.±*Ð ÜÐx. winÐ sÓeed
WhÕn thÕ wind is bÕáoming strongÕr and '=. ]..::::;iliiii]]]i]]lli''...ltg. ....'''... '...'......'...'T']I'........'.......
wind spÕÕd rÕaáhÕs alÕrt lÕvÕls, mÕasurÕs for ;1;;::|l;ili];:::i|iiiiiii'.''...''...',...''...]]:]il] :::lil:]]:::|ii]i]l]]]]:::]::]]'|:::::::]]:
avoiding dangÕrous sifuations should bÕ tak- n=s !|Þá.] ..'' .....l1..]... . ''.''.. -..............l.:.l.;;;;;i;;1;1111:l
powÕr by paying out morÕ áablÕ or bã taking Gust faátor: 1.4
rÕfugÕ offshÞrÕ with thÕ anáhor hovÕ up. TablÕ 6-5 DangerÞus wind spÕÕd of dragging anáhor
µ
Ä
í
g 200
-
á 1\n
J
100
A Guide to ship Ýandling ] .135
I
!ft!@ff! Handling of SpÕáial-PurposÕ Ships
6. Safe measures for preventing dragging anáhor
MÕastèes for avoiding dragging anáhor rÕfÕr to thÕ mÕans by whiÞh to áontrol a ship's swing motion as
indiáatÕd in SÕátion 3.1 of ChaptÕr 3, while a full lÕngth of áablÕ is paid out to inárÕasÕ an anáhor's
holding powrr. In this sÕátion, thesÕ mÕasurÕs arÕ shown with briÕf Õåplanafions and illustrations.
(a) Swing.áhÕák anáhor
A swing-Þheák anáhor is used to-
gether with another anáhor low-
ÕrÕd to around onÕ-and-half
dÕpths of watÕr on its áablÕ. This
method áan reduáe the maätude
of swing motion by about 50 pÕr-
Þrnt.
Fig.6-23 Swing-áhÕákanáhor
ä) Tho-anáhor mooring
[n strong wind áonditions, sw.ing
motion áan also be áontrolled by
mooring to two anáhors instead
of riding to a single anáhoæ a
measure that reinforces holding
powÕr. ThÕ opÕn anglÕ bÕtwÕÕn
thÕ anáhors should bÕ gâeater
than 60 dÕgrÕÕs. Two-anáhor
mooring is ÕffÕátivÕ whÕn thÕrÕ
is little áhangÕ in wind dirÕátion,
but abrupt dirÕátional áhange iÛ
w.ind direátion as in a typhoon
may put the ship at risk of foul-
ing its anáhor.
1×6 I A Guid6 to ShiP Handling
Fig.6-24 Two-anáhormÞoring
........
6.2 Nlaneuãeratíilitã of Pure Áar ÁarrieÒ (PCCs) - W.ind µffÕáts
(á) Adjusting ship's trim-by-thìhÕad
Trimming-by.thÕ-hÕad, a mÕas-
urÕ that shifts thÕ árntÕr of gravi
ty forward as far as pÞssiblÕ, is
another mrans for rrduáins thr
risk of anáhor dragging.
(d) Using bow thrustÕr
UsÕ of a bow thrustÕr áan rÕduáÕ
swing motion áonsidÕrably; thÕ
bow thrustÕr is usÕd to matáh thÕ
ship's hÕading with wind dirÕá-
tion as muáh as possiblÕ.
Fig.Ñ-25 TÓimming-by-thÕ-hÕÐd
Fig.6-26 Using bow thrustÕr
A Guide to ship Ýandlins | 137
I
6.2 ¼aneuvÕrabilitã of PurÕ Car CarÓiÕrs (PCCs) _Wind µffÕáts
!ftfisfi! Handling of SàÕáiaÌPurposÕ ships
Summary for ManÕuvÕrability of PurÕ Car CarriÕrs (PCCs)
BÕáausÕ thÕ modÕrn PurÕ Car Carrirr (PCC) has thÕ disproportionatÕly large above-watÕr hull and su-
pÕrstruáturÕ áomparÕd to its undÕrwatÕr hull, wind foâáÕ has a disproportionatÕ impaát on thÕ ship,
lÕaving it in dangÕr of losing manÕuvÕrability undÕr its own powÕr and ÕquipmÕnt.
When suáh a ship is navigating stormy seas, ship oprrators should undÕrstand thÕ limits on manruvÕr-
ability áausÕd by thÕ wind. It is also important that avoidanáÕ of dangÕr bÕ undÕrtaken at thÕ ÕarliÕst
possiblÕ momrnt.
This is ÕspÕáially important whÕn a ship is rÕduáing spÕÕd to ÕntÕr or lÕavÕ port, whÕn thÕ ÕffÕát of thÕ
wind is magnifiÕd.
DÕpÕnding on thÕ situation, thÕ ship opÕrator is rÕquÕstÕd to plaáe a priority on safÕ ÞpÕration of thÕ
ship' suáh as rÕquÕsting fug assistanáÕ if nÕáÕssary.
1×8 l A Guidí to Ship HÐndling
P,de to Shi o Handl i ns
-'
-
MaritimÕ Traffiá SafÕtv Law
1. AppliáablÕ Waters
lnland Sea&Osaka Bay
2. Trafflá ÓoutÕ
Uraga Suido
Âokyo Bay
Utaka µast
Inl and Sea
Nakanose
Tokyo Bay
Utaka West
Inl and Sea
lrago Suido
lse Bay
Mi zushi ma
Inl and Sea
Akashi Kaikyo
l nl and Sea
Bisan Seto North
Inl and Sea
Bisan Seto µast
l nl and Sea
BisÐn Seto South
Inl and Sea
Kurushima Kaikyo
Inl and Sea
140 | A Guide to ship ÝaßdIing
I
o GÕnÕral StÕÕring and Sailing RulÕs
a) VÕssÕl navigating traffiá routÕ
lD Vesse| navigating the traJfiá route
|D Vesse| not naviagating the traffiá route
3. ModÕs of Navigation
A Gui de to shi p HÐndl i ng Annex
A Guide to:ship }|Ðndling
Ö âraffiá route
pp Course of the route
b) GivÕ-way vÕssÕl and Stand.on vÕssÕl in Traffiá routÕ
(D Stand-on VesseI , ¾ Give-way Vesse| Ö Traffiá route p} áourse of the route
MÕÕting Power-drivÕn vÕssÕl
Approaáhing Sailing ship
ovÕÓtaking
HugÕvÕsse1&
FishiévÕssÕl"
Avoid
Ô-
-Y
Avoid
-Y
Avoid
âÂ
o"l. &s"rins"n,p
â
Avoid
fr .,"n,nn u"""",
W
| 141
Fishing vessei
Ô.$éide to Haßd|img
á) obligation to Naviagation Traffiá RoutÕs
d) RÕstriátions on thÕ SpÕÕd of a VÕssÕl
&{ÐxiÚlèrn
SàÕÕd
l?*ºâtÞt ZÞ*Õ
s.t:à
.:::a iill:
;li',,,i*,
r::: liirrl
g
^l l
.f'
50 m or More
\:
1:
)'
' Bousou
: :penimula::
Less than 12 Knots
Less than 12 Knots
IsÕ Baã
lnland SÕa
i
t1[i.:
"
-. Bisan Seto South T.R.l .- -
fl"
"iãi
Sakaide
Pofr
142 |^ Gui de to shi à Ýandl i ng
e) Signalling whÕn ovÕrtaking AnothÕr
lD Stand-on Vessel {Í Give-wayVesse|
A Guide to Ship Handling ;anli:'t1*S
DDD Course of the route
VÕssÕ1
Traffic route
WhistlÕ - : f
- -----+
-J Í
¿-l l
Í=\ Í D}D
+
WhistlÕ - :
Ç
l anl r_âl i E - f
f) Indiáation of DÕstination
VÕssÕl shall indiáatÕ its dÕstinationin thÕ following áasÕs:
to StarbÞard and álÕaring T.R.
to Starboard Ðnd ÕntÕÓins anothÕr T.R.
AltÕring áoursÕ to Starboard bÕforÕ passing µåit buoy.
áoursÕ Port bÕforÕ passing µåit buoã.
buoy is thÕ first buoy outsidÕ oftraffiá routÕ')
<<<
I
.-Â
.-_.¾-
>>>
E'
llj
\t
V
l À
NakanosÕ Â.R. i
IragÞ Suido T.R. l
Æl*i5×ilry"T'l. -]
Nakanose T.R. i
Irago Suido lR. ]
.l
ÁÓossing zone ]
¼iashima Â.R. and l
I
Bisan South/North i
I
Tokyo Bay
IsÕ Bay
}]×d-l"×
UÓaga T.R.
lnlmd SÕa
-.rr¿ 1
I ] i AltÕring corrrsÕ to Port and entÕring another T.R. ]
:
..E--, ÁrosstngÂ.R.
- i..-.
UÓaga SuidÞ T.R. ]
Inlmd SÕÐ l
A l ÁrossinÔ Bisan South T.R. from south and
----
AItÕnng áourse to ìtarDoaro aná Õnteßng
B : Üizustiima â.Ú.
CritÕria for Drstination
Following MaritimÕ Traffiá Information ChÐrt to bÕ àrÕpared.
. Whist|e during night. Awni*e "Ô" B wìist|e "Ò. âraffiá route
ä} Course oJ the route - - - - Base |ine at exit of â.R.
osoæthÕmPartofTokyoWm H-301-Brgg ol seV/m(IsÕbay) I{.302-BW
.NoâthÕm PÐrt ofÂäoWm H-302.BW .osakÐWin(os:Ðkabä Ý.305-Bw
Signal
A Gui dí to Shi p Handl i ng | 14l
-l
I
I
& &uxidÒ to ship ¶ar*dXimg
8) ModÕs of Crossing Taffiá RoutÕs
ThÕ ÐbÞvÕ árossing vÕssÕl may maintain more than 12 KnÞts
h) RÕstriátion on µntÕring or LÕaving or Crossing Traffiá RoutÕ
/è RÕstriátion ZonÕ
No µntÕring Â.R. NÞ LÕaving Â.R. NÞ ÁrÞssing Â.R.
TÞkã'Þ Ba1. ^.$:-
*ua"to
ÞIn thÕ áasÕ oftraffiá routÕ
l 2-KnÞt SpeÕd RestriátiÞn ZÞne
90 deg
as áIose as possib|e
144 1 ^ Guide to Ship HÐndIing
l
A Gui de to shi p Handti ng Ji *ãl *ï
i) Prohibition ofAnáhorage
No vÕssÕl allowÕd to anáhor within thÕ traffiá routÕ
µ Speáial RÕgulations for SpÕáifiá Traffiá RoutÕ
a) HugÕ vÕssÕl vs othÕr vÕssÕl
HugÕ vÕssÕl intÕnds to entÕr
NakanosÕ T.R. from Uraga SuidÞ T.R.
t!
Y
\
:
)
{.
1:
oã' ,/
{(j
!
l st Fort
' Futtsu
--\-
-\-,-
_\-
q( â..
;]ái
l
/...- \
!_,
a--.
,i
;ilzná Óo.t
\,
\
i\
- Huge vessel (Stand-on vessel)
lD Other vessel (Give-way vessel)
I raâI|á route
DID Course of the route
L_1
No mooring to a vÕssÕI lying at
anáhor in the traffiá routÕ
it .''
It
ft-r
Ó.Á'
I
i ti -
A Guido to ship Ýandlins l 145
I
A Gui de to Shi p Handl i ng
b) HugÕ vÕssÕlVS vÕssÕl whosÕ LoA is l30m or morÕ in Irago Suido T.R.
HugÕ vÕssÕl VS vÕssÕl whosÕ LoA is 70m or morÕ in Mizushima T.R.
*;
,:i
i ... .''
-L_OA*<130m )
Ó7
ËÀ'-
'NØ
/\
'. I
Avoid
Mizæsh-im-Ð
IragÞ Suido T.R.
lWait outside while
Huge vessÕl navigates T.R.
¾ l ×om < LoA < 2oom J Hugevesse(LoA>2o0m)
₠= LoA < 1×0m
Traffiá áontrol Signal Station (Irago Suido)
Sµ bound vÕssÕ1s (LoA}30m) must wait
outsidÕ of traffiá routÕ.
-:i5;oÔv &è¼*ffi
-:#oßv;
A
NW bound vÕssÕls (LoA{ l30m) must wait
outsidr of traffic route.
-:#ßßv 1
I
;ii;uÔv &èNreltr
- 70M< LoA< 2o0m (- Hugevessel (Lo°>2oom)
ffi LOA{ 70m
Traffiá áÞntrÞl Signal Station (MizushimÐT.R.)
Southbound vessels (LOA)70rn) must wait
outsidÕ of traffi á routÕ.
-:i5'sßÔv & GNreÒffi
#oßv 1
A
Northbound vÕssÕls (LoA{70m) must wai1
outsidÕ of traffiá routÕ.
;,8":DAV I
;
-:i5;ÒÔv&GW
WÐit Þutside while
Huge vessel navigates T.R.
A Gui dí to shi p ÝÐndl i ßg
-l
-t
( LoA>7Om ) I
-_____-<,
WÐit outsidÕ ß,hile
Huge vessÕl
nÐvigates T.R.
á) CrossingZone (Bisan SÕto µast & Utaka µast & W.Õst T.R.)
(D Hugevessel (Stand-onvessel ) @ Othervessel s(Gi ve-wayvesser.l
A Guide to ship ½andling &el×x×*×g
A Guide to ship Ýandling I 147
l
d) Crossing Zone (Mizushima T.R. /Bisan SÕto North & South T.R.)
] Power-driven (Stand-on vessel)
ä Power-driven (Give-way vessel)
*+D Fishing vessel
(D Hugevessel (L>200m)
& &ètde *o s8×6à 8{ar×d$6rxg
e) Kurushima Kaikão Âraffic RoufÕ
Soutll Áurrent
»{orfh Áurrent
Kurushima Kaikyo Tidal ÁuèÕnt Signal Station
Nakatoshima
A . Ò&á
l D&µ
tsÜèm ;i:oÛ} Ð El-éryé. ;Ç:ÙÙièeÙ ]
Nakatoshima Àhqæ, osuÙi-no ÝinÊ
µvÕry 10sÕá
µvÕry 8sÕá
µvÕry 20sÕá
µvÕry ·sÕá
µvÕry 20sÕá
Dourn :aaa
LastofSouth:a-
SÞuth
. - .}. ¾..
N: North CurâÕnt
: S:SouthCrrrrÕnt
NumbÕr: Knot
r\Ofr.Û :a-o
LastofNorth:aE aa) a)- a)
ama
TypÕ :°2
l FrequÕnáy :1665KI1z
. PowÕr :25W
i f -- ---
:. o-. o-Þ +CurrentSi gnal + o-o o-o o-Þ.t: Up }: Down
Naka SuidÞ (CÕntral Áhannel) = NavigatÕ with TidÐl Current / Nishi Suido (West Áhannet|= N;;;;;; ;g;;;iiiui áu...nt
!:. o
µvÕry 10sÕá
µvÕry 8sÕá
Gui de to Shi p HÐndl i ng
A Gui de to Shi à Handl i ng
f ) Kurushima Traffrá RoutÕ WhistlÕ Signal at DirÕátion ChangÕ of Tidal CuèÕnt
A vÕssÕl ÕquippÕd a whistlÕ shall givÕ following signal in thÕ ÕvÕnt
1) NotiáÕ has bÕÕn givÕn bã thÕ signal fÞr dirÕátion áhangÕ oftidal áurrÕnt
2) Direátion áhangÕ of tidal áurrÕnt is antiáipatÕd whilÕ passing Naka Suido or Nishi Suido
}.# WhistlÕ ¿
¾_ WhistlÕ ¿
ä*-*ä WhistlÕ ¿
-
¿f
1 Long blast repeatedly
2 Long blast repeatedly
3 Long blast repeatedly
Tokyo Bay hä//www6.kaiho.m1it.gÞ jpltokãowan|lindÕx.htm
IsÕ Bay hä//www6.kaiho.m1it.gojp/isÕwan/indÕx.htm
osaka Bay hé//www6.kaihÞ.mlit.gÞ jplosakawarr/indÕx.htm
Akashi Kaiäo héiiwww.kaiho.mlit.gojp/06kanku/kouanwÕb/ÕnglisËakashi.gif
Bisan SÕto hé//www.kaiho.mlit.gojp/06kan1áulkÞuanwÕb/Õnglish/bisan.gif
Inland SÕa hé/iwww.kaihÞ.mlit.go jpl06kanku/kouanwÕb/ÕnglisËÕ-kourÞjpg
Kurushima Srait http//Www.kaiho.mlit.gojpi06kanku/kouanwÕb/Õnglish,4áurushima.gif
Kanman Strait http//Www6.kaiho.mlit.gojp/kanmÞn/indÕx.htm
hé//www. kaiho.mlit. go jplO6kanku/kouanwÕb/ÕnglisËkanmon. gif
PlÕasÕ áliák Þn ''µnglish'' at the abovÕ homÕ pages.
A Gui d6 to Shi p Handl i ng | 1z
I
I
A Gui de to Shl p Handl i ng
Port Regulations Law
1.. DÕfinition of ..misáellanÕous vÕssels,'
.launáhÕs, lightÕrs, smallboats and artã áraft.
Mi sáel l aneous vesse|s shou|d avoi d those other than mi sáe|Ianeous Vesse|s When i n port
2. RÕstriátion on µntrà at Night
.¼ost of ports do not allow Õntry aftÕr sunsÕt and bÕforÕ sunrisÕ.
3. obligation of PassagÕ
.A vÕssÕl othÕr than misáÕllanÕous vÕssÕls must navigatÕ thÕ passagÕ
ÕxáÕpt in an ÕmÕrgÕnáy.
150 | A Guido to Ship HÐndIing
I
4.RulÕs for Navigation in
lD Stand-on vessel ${i Give-way vessel
& &èide tÄ g!*ip ld*ndlixg j.l ::.l:l1i:li.:il'.
No ovÕrtaking
::::=-./ --___+\=}Å
Passage
¼ÕÕting vÕssÕl
<--.\
:-.=ê -=
_r___>
Passage
No navigating in parallÕl
-µ --------+ !
½
5. Yiáinity of Port µntranáe
.µntÕring vÕssÕl shall avoid álÕaring vÕssÕl.
. This rÕgulation is appliÕd to pÞwÕr- drivÕn vÕssÕls
. µntÕring vÕssÕl shall rÕmain mÞrÕ than
3-4 timÕs LoA of álÕarins vÕssÕl.
Inside & outside
Ò
-\
#>=
g . r.. Ei s
AVOId
Inside & outside
t&
B \ Avoid
<s
=
ffi
Ö
Internati onal Regul ati on for
Preventing Collision at sea is
app|i ed i n fo||owi ng áase:
"w
Ñ. Safe SpÕed
ã,'wÖ'a
Inside ê .." outside
P / *l Avoi d
½J
,ry
e
x'l : Thi s i s not an enteri ng vessel.
Inside 1\ outside
+*
/ ₠
*2 °voi d /
:=#
*2: Thi s i s not a á|eari ng Vesse|.
ArÕa : Within a port / nÕar boundary of por1.
RÕduáÕ spÕÕd. Do not bÕ ahazard to othÕr vÕssÕls.
Á .J .l- ^- 'w
7. ^t thÕ end Þf brÕakwateÆ quay, or any othÕr stÓuáture
or vessel
A Gui de to Shi p HÐnd|i ng | 151
I
A Gt.l i de to Sl,l i à ½andl i ng
8. Small vÕssÕl (Keihin, Nagoya, Yokkaiáhi, Osaka, KobÕ, Kanmon only)
-{,
ffâ
Other than small vessel
-
vs
SmÐ|I vesseI
9. MaintÕnanáe of Channel
10. Fire Alarm
.In áasÕ o³ firÕ in port, Sound 5 (five)
prolongÕd blasts ÕxáÕpt whÕn undÕrway.
Srgnal for a vessel
Other than
Small vessel or
Miscellaneous vessel.
Small vessel
l
Ò.3
MisÞellaneous vesseI
Whi stIeorsi ren ]f f ¿f
Anáhori ng or Berthi ng
A vess e I = 5 0 0 fl :iei,i:ftêê%"'::â; *lxl#i i;i liÌÂê J"Âi.l;h ?'J;T.'"g p o rts :
A vessel < 300 *"'êlT""*Õ othÕr than misáÕllanÕous vÕssÕl at following port:
Stand-on Vessel
Give.wÐy Vessel
»fI
a#
No Dumpi ng, No Di schargi ng Sol i d BÐl |ast
´rtic|e 24-2
urÕs to
Å
pÓrvÕnt áargo from sáattÕring in por1
Ðnd v
o
iáiniry of port.
11. RÕstriátion on smoking, Õtá.
NÞ Smoking & No NakÕd light
Tanker, LNG, LPG, etá.
E,*_-30-s0jn
ïµ
152 | A Gui de to Shi p HÐndIi ng
I
A Gui de to Shi p !'{andl i ng
Typiáal Signals and Shapes
(JapanÕsÕ Larv and RÕáommÕndÕd PraátiáÕs)
1. HugÕ Yessel LÕngth}200m .MaritimÕ Traffiá SafÊty Larv
2. VÕssÕl áÐrrying Dangerous CaÓgo .MaritimÕ Traffiá SafÕty Law
reÖ A vesse| whiáh eåhibits the above |ight or shape in port does not need to exhibit signa| and
shape aááordi ng to ..Regu|ati ons for the Carri age and Storage of Dangerous Goods i n Shi ps''
3. YÕssÕl áarrying Dangerous Cargo in Port
.RÕgulations for thÕ CarriagÕ and StÞragÕ Þf DangÕÓÞus GoÞds in Ships
4. VÕssel employed for pÕrforming µmÕrgenáy Work
.MaritimÕ Traffiá SafÕtv Law
A Gui de to shi P }|Ðndl i ng
*&' G*x$de *á× s$x$à $*as×*f$s.ï×g
5. Escort Boat -Maritime Thaffic Safetã Law
6. YessÕl Õngaging in áonstruátion Þr similar opÕrationx
.MaritimÕ TÓaffiá SafÕty Law
xsuáh as drÕdging, undÕrwatÕr opÕration and minÕ álÕaranáÕ opÕration.
Speáial Signals and ShapÕs (ReferÕnáe)
DÕÕp Draft VÕssÕ1
-:i*oÔv
µ
³=]
µww
ä
?
Kawasaki Port Only
Tanker>300.000DWâ
ng Danger(
âemporary beIaying roàe(2)
.DangÕrous Áaâgo ÁaßiÕr
54 l A Gui de to shi p Ýandl i ng
l'a Gr":8de tÞ $hià &,{Ðßd!iâlg 'i::l.]i:':]}i::;:
Major FishingAreas and Tãpes of Fishing
ThÕ major fishing arÕas and typÕ of fishing
in thÕ viáinity of thÕ North AmÕriáan CoursÕ
around JapanÕsÕ watÕrs.
ffi
Red Ii nÕ means a mai n Iane of the North
AmeriÞan Course.
A Gui de to shi p ÝÐndIi nn | 'uu
156 | A Gui de to Shi p HÐndl i ng
I
JL Guid* tÞ shià ½aßtllirrg *.ra.*'*t*x
Attention:
Fishing areas are not |imited to areas desáribed
on thi s map. Fi shi ng areas are al so present i n other
JaDanese waters"
A Guide to ship Ýand|.ns l 157
*& &ax*de 8á× sh*à 8{amdtÙr×g
Tãpiáal Fishing MÕthods & Gear
0
158 l A Gui de to shi p Ýand|i ng
A Gtride tor stlip ½antlling ,&xx*x
A Gui de to shi p Ýandl i ng 159
I
A &èide tá× ship
,rr:: ..:::
,ttt_ ::
Typiáal Inland SÕa Fishing MÕthods
Fishing Season : January-November
Peak Season : February-August
Fi shi ng Area : Bi san Seto µast/North/South TrÐffi á route and vi ái ni ty of the above routes.
Time of Fishing : From sIaák tide ti|| next s|aák tide.
-n:
saák net
ln the áase of ×0m Water depth
saák net is usua|ly 12m under tÌe Water.
k- Ðb.80m ------.--------r|<- Ðb.60m
ab.125m
S0">r
(GeneraãL.z
--- *"Û^"
-*Û- -¸
*alããgg×*xxw
µ
N
i
O
î
,,¼ito,, bÐrre| is on board or near ship.
Fishing Season : Spring-Autumn
Peak Season : May & June
Fi shi ng Area : Inl and sea
Ti me of Fi shi ng : ab.2 hours
North or West end
Setti ng net : Yel l ow fl ashi ng l i ghl O
Li fti ng net: Whi te |i ght ¾
swi ngi ng Whi te Ii ght i ndi áates sal e si de
(*1,
rj
e
T
Yellow
Yellow Flag
Red Light
Red Flag
160 A Gui de to shi p Ýandl i ng
D
o
o
qt
,1
$à
o
d
Þ
o
o
t
t
(o
o)
Traffiá Advisory SÕrviáÕ Center CommuniáatiÞn and Information
RµOoMMµNDAÂ|oN oF ÂHE RoAD |N ToKYo BAY AND oâHµR BAYS AND sTRA|âs lN JAPANµSµ WAâµRS
http://www.kaiho.mlit.go jp/syoukailsoshiki/toudai./navigation-safety/download,/download_info06.htm
Jaàan áoastguard Laws & Regulations
http : l / nippon.zaidan.info/seikabutsu/200 1 /00500/Þontents/O0002.htm
hä://www.kaiho.mlit.go jplsyoukai/soshiki/toudai/navigation-safÕty/download/down_bc/english,/par12.htân
Cal l Si gn µL FAX
Home Page lnformation
ÂoKYo
MARÂ|s
áontaát vHF Á|1.|6l|3l|4122
+8
-46-843-862724
http //www6.kaiho. mlit.go.jp/tokyowan/
http :/°ß'ww.toukaibou.or.jp/
Information
SÕrviáÕ
Traffiá Control
+8
-46-84×-0621
+81-46-844-2055
RÕstriátion
+8
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http /°ètèw6.kaiho. mIit'qo. ip/tolgowan/oulIshio/ou IIshio.htm
WÕathÕr
+8
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r81-46-844-2055
http /°tvww6.kaiho.mIit.go,jp/tokyowan°rueather-pdweatherindeå. htm
IsµWAN
MARTIS
Contaát v}lµ Áh'1,6l1×l14122
+8
-531-34-2445.6
http/^^,WW6. kaiho. mIit.go.jp/isewar/|eaf IeÃengIisËengIish. htm
Information
SÕrviáÕ
GÕnÕralWÕÐthÕr
+8
-5×1-×4-2666
r'8 1-53 1-34-2888
+8
-5×1-×4-2×3×
NAGOYA
HARBOR
RADAR
ContaÞt
ÃIlF Áh.16l|×lI4l22
+8
-s2-398-0'712
http://www6. kaiho. mlit. go.jp/nagoyako/
Information
SÕrviáÕ
A11 InformatiÞn
+8|-52-×98-0.714|8|-52-×98-|×79
OSAKA
MARÂl s
Contaát ÃHF Áh.|6l|4l22
+8
-.799-82-30·0"
http ://www. kobe.kaiboukÕn'or.jp/web/jap/reáom men/
osaka_Entranáe'htmI
http ://www. kaiho. m lit.go.jp/06kanku/kouanweb/english/akash i. gif
Information
SÕrviáÕ
Traffiá Control
+8
-,799-82-×04×
|81-.799-82-×046
RÕstriátion
+8
-799-82-3044
|8|-078-×32-6×07
WeathÕr
+8
-799-82-3040
BISAN
IØARTIs
Contaát vHF Áh'16l1,×l1,4l22
+8
-877-49-2220.
hä/,,\èww.kaiho. mIit.go jp/06kanku/kouanweb/engIishzbisan.gif
Information
SÕrviáÕ
Traffiá ÁontÓol
+8
-877-49-5166
181-871-49-1199
WÕathÕr
+8
-8'7'7-49-1041
r81-87',1-49-1149
hä/°èww. kobe-kaibouken.or'jp/
Fishing NÕ1
|8I-8.7.7-49-××É
KURUSHIMA
MARTIS
Contaát
v}lF ChJ6l1.×l1.4l22
+8
-898-3 1 -9000
http//wtètv6. kaiho. mIit.go.jp,&urushimÐ/
http/°èww. kaiho. mIit. go.jp/06kanku/kouanweb/engIish/
Information
SÕrviáÕ
Traffrá Control
+8
-898-3 1-×636
r-8 1-898-3 1-4646
WÕathÕr
+8
-898-31-8177
r-8 l-898-3 1-4646
kurushima.gif
KANMON
¼ARTIs
Áontaát
VIIF Áh.|6l|4l22
+8
-9×-×.72.0099
http ://www6.kaiho. mIit. go.jp/kanmon»ndex-top. htmI
Information
SÕrviáÕ
Al1 Information
+8 1-93-38 1-3399
|81.9×-×72-2,|41
rLLPJ/
http //wtèw.kaiho,mIit" go jp/06kanku/kouanweb/engIish/kanmon.giI
Common
PilotagÕ Distriáts in Japan
6. RUMOI
- *"Ê
28. HANSHIN
,g
A Gui de to Shi p Handl i ng
27. OSAy,WAN
30. SAKAI'
\
29. NAIKAI \
5. oâARU
4. HAKoDAâµ
10. AKITA-FUNAKAWA
11. SAKAâA
17. NIIGAâA
18. FUSHIKI
. 19, NANAO
25.
32. KoMAâsUJlMA
2. âoMAKoMAI
-/,12. ONAHAMA
/ /1×'K^sH|g^--
×1- KANMON
33. HAKATA
34. SASEBO
35. NAGASAKI
36. SHIMABARA-KAIWAN
×7. HososHIMA
38. KAGOSHIMA
/ ^',l' r
l
!
I
×í. ènÝntl
l?l
*l
TAGONOURAi/
21. SHIMIZU
.p1zá.owÛsÒ'i.]-1
26. *AKAYAMA-a..,,"orau-il--*
Pilot Distriáts & TelephonÕ/FaásimilÕ Numbers
162 l A Gæide to Ship }|ÐndIing
I
Compulsory PilotagÕ (PilotagÕ and Navigation Law )
Âhe áompu|sory pi|otage areas in Japan are broad|y divided into two áategories; i.e., the áompulsory areas in ports and
those in waters iná|uding áhanne|s, straits and adjaáent port(s).
Port
Areas
Category A
YokosukÐ
SasÕbo
NahÔ
(*)
. VÕssÕls offoreä registy Ùth gross tonnagÕ 300 t,ons or morÕ'
. VÕssÕls of JapÐnesÕ rÕästry Ùtlr gross tonnagÕ 300 tons oâ abovÕ ÕngagÕd in intematiÞnal
voyages or
. VÕssÕÌ of Japanese réiÜry with gross toèlage 1,0Ä tors oâ above engaged in domÕstiá
sÕrØÞe.
VÕssÕls with gross tonnagr 3,000 tÞns or above.
VÕssels áarrying dangÕrous goods are thÕ samÕ as (*).
. VÕssÕls with gâoss tonnagÕ 3,000 tons oâ above. Vesseis loadÕd with dangerÞus goods Ðnd
. VessÕls ÕntÕring/lÕaving sÕátions 1 - 4 ofWakamatsu arÕ thÕ same as (*).
Waters
áategory B
Toäo Bay 1inátÜéÓorìot
êkyq álßêamdKim)
Ise.Mikawa Bay 1ìátuÐØg
Pofu of NagoyEYokkaiáhi, Kinué
èd¼ik¼)
osaka Bay 1ìáluÐ:ngÓorì or
I(oÌÕ' oÜkÐ' Ýamm md°k´hi
sµaiO
Bisan Seto
(including Port of Mirhim)
Kurushima StrÐit
Kanmon ChÐnnÕl
(PÐsif,g vä]s)
. VÕssÕ1s with gross tonnagÕ 10,000 tons or above.
[!f, Japan Coast Guard reáommends fol|owing safety measures in addition to above CompuIsory Pllotée Réuirement.
Uraga Suido TraffiÞ Route and Naka.no-Se Âraffiá Route and °djaáent Waters
ThÕ following vÕssels should take a pilot on board:
(1) A vÕssÕl Õntitled to fly thÕ {lag ofa foreign áountry.
(2) A vÕssÕl ÕntitlÕd to fly thÕ Japanese flag, commÐnded by a mastÕr whÞ dÞes not havÕ suffiáiÕnt sÕa-going serviáe and
ÕxpÕrienáÕ of navigating in Tokyo Baã (Tokyo V/an).
Irago Suido Traffiá Route and Adjaáent Waters
ThÕ following vessels should takÕ a pi1ot on boÐ:d:
(1) A vÕssÕl ÕntitlÕd to fly thÕ flag of a foreign Þountry.
(2) A vessel Õntitled to fly thÕ JapanÕse flag of 1 30 m or more in lÕngth ovÕr all pâescribed by thÕ MaÓitime Tâaffic SafÕty Law
as a vessel áarrying dangeâous cargo.
Sth Regiona| Coast GuÐrd Headquarter reáommends vessels take the following safety preáautions
ThÕ fÞllowing vÕssels should takÕ a pilot on board:
(1) A vÕssel entitlÕd to fly thÕ flag oia forÕign áountry.
(2) A vessÕl ontitlÕd to fly thÕ JapanÕse flag, áommanded by a master whÞ dÞÕs not have suffiáiÕnt sÕa-going sÕrvice and
ÕxpÕrience of navigating in °kashi Kaikyo Traf,fiá RoutÕ.
Bisan Seto South Traffiá Route, Uko East Traffiá Route, Uko West
Tra{fiá Route, Mizushima Âraffiá Route and Adjaáent Waters
ThÕ fÞl1owing vÕssÕls entitled to flã the flag of a fÞrÕign áounä should take a pilot on board:
(1) A vÕssel áarrying dangerÞus áargo prÕsáribed bã the ¼aritime Traffiá Safety Law.
(2) A vÕssÕl áommandÕd by a master who navigates SÕto Inland SÕa for thÕ fiâst time.
Kurushima Kaikyo Traffiá Route and AdjaÞent Waters
ThÕ fÞllowing vessels ÕntitlÕd to fly the flag of a foreign áounä should takÕ a pilot on board:
(1) A vÕssel áarrying dangerous áargo presáribed by thÕ Maritime Traffiá SafÕä Law.
(2) A vÕssÕl áommanded by a mastÕr who navigatrs SÕto lnland Sea for thÕ first time.
A Guide to ship Ýandline I lÞ×
A Gui dÒ to Shi p }|andl i mg
JCA Voluntary Traffiá SÕparation SáhÕmÕ
(Publ i shÕd: 0 1 -Septemb er2002)
ModÕ of Navigation in Traffiá SÕparation ArÕa and its Viáinity (Voluntary)
WhÕn naÙgating a traffiá sÕparation arÕa, vessÕls shall, in prináiplÕ, follow thÕ rulÕs as shown bÕlow
The traffiá separation sáhemÕs in this text do not apply to thÕ traffiá separation sáhemes referred to
in Artiá|e 10 Paragraph (a) of the InternationaI Regu|ations for Preventing Co||isions at Sea.
tt A vÕssÕl using a traffiá sÕpÐration sáhÕrnÕ shall procÕÕd in thÕ apprÞpriatÕ trafiá lanÕ in thÕ gÕnÕral daÕátion of traffiá
flow dÕsignatÕd for that lanr.
@ A vessel using a traffiá sÕpÐration sáhÕrnÕ shÐ.ll so fÐr as praátiáablÕ kÕÕp álÕaâ ofthÕ sÕpÐrafion zonÕ.
@ A vÕssÕl rèing a tÓaffic séaration sáhÕmÕ shall normally join Þr lÕavÕ a t×ffiá lanÕ at thÕ tÕrminÐtion of thÕ lanÕ, but whÕn
joining or lÕaving from thÕ sidÕ shall do so at as small Ðrr anglÕ to thÕ gÕnÕral dirÕÞtion oftÓaffá flow dÕsignÐtÕd as praátiáablÕ.
@ A vÕsse1 shall avoid árossing traffiá lanÕs. IfshÕ is obligÕd to do so, thÕ vÕssÕl shal1 áross as nÕarly as praátiáablÕ
at a right anglÕ to thÕ gÕnÕra1 dirÕátion of traffiá flow dÕsiàatÕd fÞr that lanÕ.
st A l,ÕssÕl not using a traffiá sÕparation sáhÕmÕ shall avoid it by as ÙdÕ a maéin as is praátiáablÕ.
@ A vÕssÕl, othÕr than a árossing vÕssÕl, shall not normally ÕntÕr a sÕpÐration Zonr ÕåáÕpt in áasÕ of rmÕrgÕnáy to avoid
immÕdiatÕ dÐngÕr.
@ A .,ÕssÕl navigating in arÕas nÕar thÕ tÕrminations of traffiá sÕpÐration sáhÕmÕs shall do so with partiáular áaution.
@ A .,essÕl requiring no passagÕ throuä a dÕÕp water route shall so far as praátiáablÕ kÕÕp álear of thÕ dÕÕp watÕr routÕ.
Off Su-no-Saki and Tsurugi Saki Off Kazahaya Saki
N
W(+>µ -a ft
Jt./
1^e/
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\{
r\
µÍ TSu
{(æ
\4-n-Ûr,
Ä/
Ä/
Y,
g-(Lo!L
Ref.Charts
JPN 51,80,90,1062
B.A.95×'×360'×548
D|'°^ 97 1 40'97 1 42'97 1 4·
eä
"270"
;sl
Þi -+
New
<2æ
'^t >
ol *i
OI N
Rei-Charts
JPN 51,80,90,1062
B.A.953'3360'×548
D|'° ° 97 1 40'97 1 42'97 1 43
'-'l
'll
.l
164 | A Guide to ship ÝÐndIing
I
I
Off Shio-no-Misakr
A {ièide to slrip !"{Ðrrd!img ll.;×;l*x
off MikomotÞ Shima
N
A
w.ä'Ò
v
s
tç-ÓJµÙ
¼ikomoto Shima
¸',':l
off Hi.nÞ.Misaki
N
w.Ä'Ò
v
('27¾.')
<-___*__-
2M 1M 2g
t
?
·.2¼
,A
OI
OI
/,ffitñ
=sl
Nt
Hino-¼isaki
A
sС
---->
(oeo")
{i.µ I sìima
Ref.áharts
JPN 77,150á
B.A.951 ,2875 . ------_¿ l
DMA97200 o 2 4 6N¼
Off Daio Saki
N
A
w.ä'Ò
v
s
Ref.Charts
JPN 70'93'1 051 '1 05×
B.A.952'2957'×650
Dß/A 971 80'971 81 ,971 82
³-'-r_-_I .
0 2 4 6Nrvl
Irago Suido µntranáÕ DÕep WatÕÓ Route
N
A
W<#>µ
v
v
J
,/\
.? Û\
--n
(
tÓ-4 ?
'-" I
-I
,I
oLl
vessels
A Gæide to ship ÝÐndlins L 165
I
:
lll
:
t
¿
MALAYSIA
. MALAáOA
'.lr
='.. - '-,
×
'4
êâ?"#
RUPAT
,,' -_ -.-..- ,,
-! - '- , .' -- ,:::./
''i --.:'-- ..r'
\
\
-.: -a
SUMATERA
' . .' .\.:i:.l\' ÒµNGKAL|S t . t
-'r':r':" !'l:l::l'
'\,,,.-,-"--'
-,..:.:i \ , \, -- -'i...... .
i'.lt .l '\'1,..,.
t] 't1-), PADANG
l'-l
.''.. . ..:
\""*-* "i
l* ** =.,"*>
l=,*´
166 l A Guide to ship Ýand|ing
sl °
i°LAcáA
ÂG ÂoNoR
,*
\ _..:::,
ê
ê::
êt
ê
_ :,:
,/
.Ll S t.
JOHOR BAHARU
SINGAPORE
°D°NG
/
-*--
WÕstbÞund f,ftf) Ýo.,burgh Light HÞusÕ
fift!) .loìÞ. Fairway
GEEI singÐpÞre Strait
GEID ßuffl.s-Pu Iãu Keáil
GEE) offPu Pi.urg
(GEED Þtâß..mai, PÞrt Diákson
GµE) Þ.'" FathÞm Bank
µastbÞund (EµE) o,'Õ FathÞm BÐnk
GED âs.MÕdang
GEID âg.GÐbang
GµlD Long Bank
GEID p" Iãu Keáit -TakÞng
lftlp SingapÞre
GEt¸) Joho. FÐirrâaã'
GEIB Ýorsburgh Light housÕ
Symbol
Crossi ng Area
Conspi á Ii ghthouse
O Pilot station
i-ii:r.;r+:-.:s: Separation zone
20m áontour
1 0m áontour
A
s^?
BUK|T sµGµNÂ|NG
êçfl . -t
i r*ì .. ..-Ð
RANGSANG
A Gui de to shi p ÝÐnd|i ns 167
I
-Eb.(ê to Ship Haßdling
-
r;t,x
WÕstbound
´l'
*
o
Ö
ffi
I
I
I
I
I
I
Symbol
Crossing Area
Conspi á |i ghthouse
Pilot Station
Separation zone
20m áontour
10m áontour
Own ship (Large vessel)
Other shi p
Group of fi shi ng vessel s
Buoy
1è t ^*toS|räHaßdtißg
l
or Strait QntÓanáÕ i-'!,
..Ój -}..^^.^^^ ..] l
Strait QntÓanáÕ /-'\ l !/
() Departure vesse|Ôrough Johor passage
O Departure vesseI from Speái al Purpose Anáhorage (rare áase) ''' ,1
₠)âowing Vesse| (barge) \-/
& Gui*e to ship F*and!iïg 'iiii..1'1; ;.11';1;1................:
i'..!
'.À,
A Gui de to shi à ÝÐnd|i ng | 169
I
I
& &Ötá*e *ï> s&×3p &**x×dl*xxg
17O A Gui de to Shi p Handl i ng
_- l
A Gui de ta shi à ½andl i ng &;:r×gx
\ (oWestbound vesseI.áomi ng from Dumai
-l)Veisel makiÑ-o U-turn in árossino Ðrea
Q Departure vessel from Port Kelang
O Meeting vessel entering Port Kelang
Os"'"-Ù"y u".."l ou"ÙÚ;; ;;;. overtaken n"u. onÙthom Bank
O*Vessel proáeeding in separation zone 1] \ .-.-
r\ \=.-o>{
] -...---) Pnrt ºl qnÞ t \
-\_l!-
A Gui de to shi p ÝÐndl i ng | 171 l
A Gui de to shEp ¶amdl i ng
µastbound
FathÞm Bank
*\a
ê-çi-=?êÞlÕ Fathom Bank Lt
---ñ!_
--. -...]]-....,=₠l.:.- (-..-\..===.:
At-771
l _--= | I
^^1ç-
*A-:- - --*---1Q1=:
+---lll \2 \- =^---)
¾
O-+,,
O-,,)
?× refuÜ-**- !
ê ---\
-J
--=<\--=J I
.172 | A Guide to ship Ýandling
A Gui tl Õ tÞ Shi p Handl i ng
--) -
t
t
r
³
!
t
@)LÞng Bank
äConvergent vesseIs to west of Long Bank
oWestbound vesse| proáeeding near Þenter |ine off Pu Pisang
₠)SmalI áraft & barge árossing separation zone near-Pu-|ãDkÊÐil-.*--...-*-1
*:===µé,yäé@Ù.- '*.* ""t-ês.:+..*=u*
t -4 ==---Êê --Ý
A Gui de to shi p ÝandIi ns | 17×
A Gui de to Shi p Handl i ng
174 ' A Gui de to shi p Ýand|i ng
'l
'& &uid* tÞ slrip À{aÒr*!!Òg
A Gui áte to shi à ÝÐndl i n s | 175 "s |177
- r E
& Gèi dÒ tCI s}âi p &{axxdl Ùmg
Froud NumbÕr
RÕlationship bÕtwÕÕn Ship LÕngth and SpÕed
0.25
0.24
0.23
0.22
0.21
0.20
0.19
0.r 8
0.17
0.16
0.15
0.14
0.13
0.12
0.11
0.10
0.09
0.08
0.07
0.06
0.05
10 11 t2 13 14 15
3hi p sàeed {knÞts)
180m
200m
22Om
240m
260m
280m
300m
320m
340m
360m
380m
400m
s
lí
{:
:3
x
ñ
:3
*
l-t
;
tl*
176 | A Gui de to Shi p tl andl i ng
I
Ôt Gr,iide to Ship ½anátlimg i}'*i?{*x
á
Ä
Ä
6
í
, Ship:. Sáitisfañtioß to l¼o]stqbilily,á1ite1ia.or,ñQ.uive|ñ1t
v
Wave: WaveIength>0.8xship Iength, HlÒ>0.04åship Iength
µstimate ,l, Â, and ,Y, Where â=o's,/^
Y
Ship áourse: Wave direátion is 0.to 45.from the stern.
Y
µnáounter Wave period, µ (seá)
v
lf ship's speed isr
(1) i n Surf-ri di ng zone
Reduáe to speed zone (2)'
Fig.l
µnáountÕÓÐnglÕ x
V ftßot)
ilLln) 5'U
^ 2.8
126
| 2.4
| 2.2
| 2.0
1.8
1.6
1°
17
1.0
03
v (kßot)
-r^
| {seá) J.U
, 2.8
l l Ò
t--
| 2.4
122
l z0
I3
1.6
1.4
11
1.0
03
J
J
--+ (2\ in marginal zone
Reduáe to speed zone (3)
when large surging is felt.
(3) beyond the zones
Fig.2
Diagram indiáating dÐngerous zonÕ duÕ to surf-riding
v
' :.: ..:ll]N;!i:.E¡'ll..il':l].
v
Váosl
3'0 â
,:8. P|ot V (Únot)/Â (seá) versus l on Figure 3
LO
24
22
2.0
t3
1.6 , ,,
'i.i''" Fig.3
|-2^ Diagram indiáating dangÕrÞus
Ö ZonÕ o³ÕnáountÕÓi ng tÞ
;i hi gh wÐvÕ gÓÞup Ðnd ÓÕl ati on
u.o
0.4 bÕtwÕen mean wave period
02 and ÕnáÞuntÕr wavÕ pÕriÞd in
0 following and quartering sÕas
L: |enqth between DerDendi áu|ars
of the ship (mere,)
V: aátual ship speed (knot)
T: mean wave period (second)
µ: enáounter wave period (seáond)
âR: nÐtural rol|ing period(seÞond)
,l: average length of the wave (meter)
l: shi p.s enáounter anq|e to wÐve
(degree). Ðs shown in-Figure '1
H1µ: signifiáant Wave height (meter)
î"
900 lBeam seal
70"
70"
îo
Qnor i
-L0 05
{- Â/ÂÕ
Y
l{]vff Ù)]]is:i0iifia:qa!g!igii'9]ii'ilii:reijÇáe.tt]e:qpeeÄlto:ogmelorliàliiie6;;i
Y
, !t.vß1rl.is .ìrÙlg]'!'!]gÐiigÄÄiÙ0,|!ÙiipeeäendlgoÆtgQ]l1]l
v
.]{:Âi:is.;Ùii''äÄio:éÙ;ii*!₠!Ùqih6ïÄälÄrlií. -
't âake i nto áonsi derati on the mi ni mUm sàeed for mai ßtai ni n9 áoUrse áontroI of shi p.
+)
]i:]i!lli!!gÄ
-i
I
A Gui de to Shi ß Ýandl i ns | .|77
I
RÕfÕrÕnáÕs
o #)| ä": ³ffi;.I }*fl¡"-ft] ifrt¡ 1977
(S. IwÐi: ''on Ship Handling' New µdition'', KÐibundotl,|971\
.4µ BzäA: ³+*ïAµ-#(tg?fifi;Tffi)-] ßtÈ¡#³Ô 1998
(K' Honda: ''IntrÞduátion tÞ Ship Handling' 5th µdition''' SeizandÞu ShotÕn, 1998)
.ffi'± ft.Rltå ä1#| ³t*ïAO*âñ] iµt¡ i988
(S. Hashimoto and H. YÐbuki: ''FundamÕntals of Ship Handling''' KÐibundÞu' 1988)
¾äï,d At: ³ïAfl¡Ot¡A)lCI;t1ffiµÔ] åÖ+t t958
(H. Kikutani: ,.StÓuátuÓÕ and µquipment ÞfShips'', TÕn'nÕnshÐ' 1958)
o ig$ffÐ : ³^éïÌ.O,ffigi*Olïi,ilPdµÒ,fi 1 @F.fuA₠\t+#) tszs
(¼inistÓy of TranspÞrtation: ''µåisting Mooring System of LaÓgÕ-sizÕd Ships Ðnd its OpeÓational PÓÞblÕms.,, TÕåtbÞÞk for
CoÓÓespÞndÕnáÕ CÞursÕ of ¼ÐÓitime AáÐdem5 l975)
.ÃLÁÁËt.*'* : ³Vl-áál:ffif ê+# -*il;¾,f47l".-) J5ÛèAgÓ¡i 7977
(Study GÓoup ofVLCC: ''Ten ChapteÓs fÞr VLCC -Àoints Þf thÕ Ship Handling_' Seizandou shotrn''' 1977)
. µ+ïAµt#A : |*fl;>+ñ++ ("Ä-) 1 1994
(Japan Captains'AssoáiatiÞn: .'RefÕrenáÕ DÐtÐ for Ship Haßdling <PaÓt 1>''' 1994)
. HAf,Aµi#A | |tsef,A>t,Atr kD-) J 1995
(JÐpan CÐptÐins'AssoáiatiÞn: '.RefÕÓÕnáÕ dÐta foÓ Ship HÐndling <PaÓt 2>''' 1995)
¾ µ4AïAti'A : ³ï3læ]*fr,t,t+,>,tr''ÌJ 198t
(ThÕ Soáiety of NÐval AÓáhiteáts of Japan: ''PrÞáeÕdings Þf the 3rd Sãmposium Þn Ship MÐnÞÕuvrability''' 1981)
O µAAïAIÙA : |*Ýx;'|+6fr*'Þ-#¡l.lijìµ] 1995
(The Soáiety of Naval AráhitÕáts of Japan: ''ResÕÐÓáh on Ship MÐnoruvÓÐbilty and its Appliáation to Ship DÕsign.'' 1995)
c t]AffiiE+A : ³ïAflAOffiåiµffiI:rï"{Ì','f''Ì) 1973
(The Nautiáal SoáiÕty ofJapÐn: ''Symposium on Ship HÐndling in Rough Sea,.' 1973)
aHE -*ä.: ³iÒi¡.f,+Dµiq.äatêFä.tr'*\,'#iLIï*L.tL¡iétl6+*ïAi:íl,'{] µ4ffi,iÄ++=# ä126+ 1995
(K. Takaishi: ''DangÕrous WÐve GÓouping Phenomena in Following Ðnd Quartering SeÐs and AppliáÐtion to OpÕrÐtiÞnÐl
Guidaßáe',, Navigation No. 126' Jaàan Institute of Navigation, 1995)
.lµä -+ : ³¡tr?×*LrAÅtslO*¿;ft] ÙLl]ä#,A' 200t
(A. Fukuáhi: ''KnowledgÕ Þf Upper Air WÕÐthÕr and its Faå Map.', SÕizandou ShotÕn' 2001)
O IMo rÕsolution MSC. 137 (76): ''Standards for Ship ManoeuvrÐbility'., 2002
O IMo Msá,/áirá. 1053: ''µxpianatory Notes to the StÐndards for Ship Manoeuvrabilty'', 2002
.I. C. Álark: '.Ship DynÐmiás for MÐriners'', NÐutiáal Institute, 2005
o U. K. Hydrographiá offiáÕ; NP 100: ''The MÐriner's HÐndbook'', SÕventh edition 1999
o ¼inistry of Defense (NÐvy): ''Admiralty Manual Þf SÕamanship, vol.è"' 1983
o µdward J. Lewis: '.Prináiples of Naval Aráhiteáture VolumeÈ''' SNAMµ' 1989
. D' H. MaáµlrevÕy and D. µ. Maáµlrevey: .'Shiphandling for the Mariner (fourth edition).', Cornell Maritime Press, 2004
. J. ¼. J. Journee and JÐkob Pinkstaá ''Introduátion in Ship HydromeáhÐniás'', Delft UnivÕrsity of Teáhnology, Draft edition, 2002
o IMo ¼sá/Cfuá. 707: ''Guidanáe to the Master for Avoiding DangÕrous SituÐtions in Following and QuartÕring SÕas''' 1995
o Joost F. Besier: ''Crossing the Bar'', NÕlson ¼arlborÞugh Institute of Teáhnotogy, 2005
o Mooring µquipmÕnt Guidelines 2nd edition 1997 (OáIMF)
¾ µffeátive mooring 2nd edition 2005 (OáIMF)
o InternÐtional Safety Guide for oil Tankers and Terminals 5th edition (OáIMF)
¾ JÐpan CoÐst Guard Laws and Regulations - Nippon FoundÐtion LiÌrary (Japan Coast Guard Assoáiation)
{ JÁA Video)
o MÐneuvÕring and Control Charaáteristiás of Speáial Type Ship Part l Foáusing on the Wind Pâessure µffÕát on a PCC
o Maneuvering Ðnd ContrÞl ChÐraáteristiás of Speáial Type Ship Part 2 Anáhoring and Mooring of a PÁC
O MÐneuvering and Control ÁhÐraátÕristiás of Speáial Type Ship Part 3 In-harbor Ship Handling o{ PÁCs
O ¼aneuvering Ðnd Control ÁharaátÕristiás of SpÕáial Type Shià PÐrt 4 Ship Handling of PCÁs in HeÐvy Seas
¾ Ship Handling in Following Seas
o Ship Handling in Head and CountÕring Seas
o MÕteorolÞgy for Safe Navigation in Tropiáal and µåtratropiáal CyálonÕs
o Ship I{andling in RestriátÕd Waters VolumÕ ] Ship Squat and Shaliow WÐter µffeáts
O Ship HÐndling in Restriáted Waters VolumÕ II Bank µffeát and Interaátion BetwÕen Two Ships
¾ Ship Handling in Restriáted Waters Volume III Anáhoring
¾ Ship HÐndling in Restriáted WatÕrs VolumÕ IV In-HÐrbor Ship HÐndling
O MÐneuverability of Very Large Shiàs
o ManeuverÐbility Þf Pure CÐr CÐrriers -Wind µffÕát-
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