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Патент USA US3085541

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April 16, 1963
Filed March 28, 1962
Jacob Rab/‘now
Harold J. Rosenberg
a. ?wm ¢
7444 a”. fMWM
nite States
Patented Apr. 16, 1963
appreciably reduce the draft of the vessel. With large
area airfoils having a reasonable lift coefficient and with
Jacob Rabinow, Takoma Park, and Harold J. Rosenberg,
Silver Spring, Md, assignors to Rabinow Engineering
Co., Inc., Rockville, Md.
Filed Mar. 28, 1962, Ser. No. 183,118
4 Claims. (Cl. 1l4—39)
crisp winds, for instance, of the order of 25 to 30 knots,
enough aerodynamic lift can be produced to have the
boat operate in a skimming mode.
Accordingly, another object of ‘our invention is to
provide aerodynamic lift producing means for a sailing
vessel, which relies on the wind velocity to produce lift
This invention relates to sailing craft, and particularly
to an aerodynamic aid for sailing, especially when there
in such a way as to produce moments which prevent or
at least attenuate heeling.
A further object of the invention is to provide an aero
is a crisp cross wind.
dynamic lift-producing device for a sailing vessel where
Our invention is concerned mainly with stabilizing a
the lift can be directed in such a way ‘as to reduce the
sailing craft by preventing heeling although, as will be
from a keel), and these have been directed toward over
coming instability by two methods. The ?rst is to pro
draft of the vessel.
In the simpler form of our invention, which has been
selected for illustration, We have two outrigger \airfoils
whose lift ‘acts through moment arms to exert reaction
forces on the vessel in the desired direction. A feature
vide ballast on the sides of the sailing craft such as dis
of our airfoil arrangement is that the airfoils can be
patent points out advantages in substituting airtight
cute a turn in either direction.
seen later, there are other inherent advantages.
There 15
have been prior efforts to stabilize sailing craft (apart
closed in US. Patents No. 543,210; and 1,371,139‘. The 20 adjusted so that the sailor can select both the magnitude
and direction of lift which he desires. This is to enable
earlier of these patents discloses that it has been common
the sailor to take advantage of the ‘aerodynamic lift pro
to provide a lee-board hinged or ?xed to the side of the
ducing device regardless of whether it is desired to exe
vessel to contact the water when the vessel heels. This
To our knowledge, no one has, in the past, relied on
shelves for the lee-boards. These shelves are hinged to 25
aerodynamic forces to help stabilize 1a sailing vessel in
the sides of the boat and can be made to contact the
the manner which is disclosed herein, although there has
water. When the hinges are locked, the shelves func
been e?iort along these lines by relying on shifts in ballast
tion as outrigger pontoons. The effect is to limit heeling,
or the crew shifting its weight or outrigger pontoons.
in contrast to preventing heeling which is an ‘aim of our
30 None of these methods provide the above discussed ad
vantages of our invention. In addition, at low (compared
The other method of solving the same problem is to
use pontoons of various con?gurations and designs. For
example, US. Patents No. 1,709,219 and 2,756,711 dis
to airplane ?ight) wind speeds encountered in sailing, the
magnitude of aerodynamic lift is proportional to wind
pontoons remain in the water and hence, they produce
Also, by having the airfoils adjustable, the sailor is able
speed. Thus, the more that a cross wind tends to heel
close two different ways of relying on outrigger pontoons
to stabilize a sailing vessel. In both arrangements, the 35 a vessel, the greater the aerodynamic restoring force.
hydrodynamic drag.
Although physical embodiments of our invention re
to select the amount of lift (restoring force on the vessel)
which he desires (within the parameter of available lift).
This preserves an element of sailing skill.
Other objects and features of importance will become
?cial. We have observed that heeling of a sailing vessel 40
apparent in following the description of the illustrated
is ordinarily caused ‘by cross winds, and we have made
forms of the invention.
the further observation that the same cross winds could
FIGURE 1 is an end elevational view of a conven
be used to generate aerodynamic lift to either ‘attenuate
or substantially eliminate heeling. By relying on aero 4.5 tional sailing vessel equipped with our device.
semble outrigger pontoons, the resemblance is only super
dynamic forces we eliminate a serious di?‘iculty encoun
tered in using outrigger pontoons for the same purpose.
In brief, we avoid all of the hydrodynamic features of
outrigger pontoons including hydrodynamic drag. Fur
FIGURE 2 is a top view of the vessel in FIGURE 1,’
with the sail omitted.
vFIGURE 3 is a schematic perspective view of a typical
control system for our lairfoils.
FIGURE 4 is a fragmentary perspective view showing
thermore, should an outrigger pontoon stabilizer bu?’et, 50
a modification.
the sailing vessel is subjected to erratic torsional forces
In the accompanying drawing FIGURE 1 shows a
due to the successive engagement and disengagement of
conventional, small sailing vessel 10. The sailing vessel
the outrigger pontoon with the water. The torsional
has a hull 12, a deck 13, a mast 14 with its sail 16, and
forces referred to are those caused by the hydrodynamic
drag at the time that the pontoon engages the water, this 55 a keel 18.
Our aerodynamic lift-producing device is composed of
force having a reaction in the boat itself tending to turn
airfoils 20 and 22 having their spans lengthwise of the
the boat about a vertical axis passed through the pontoon.
center line of the vessel. This arrangement is not critical
Our invention, which relies on aerodynamic forces in
and, in fact, to obtain a lift component when the vessel
stead of buoyance of a pontoon, has no reliance whatso
is moving forward, and the wind is essentially fore and
ever on the water to ‘obtain a reaction. Instead, we rely 60
aft, the airfoils could be arranged with a sweep angle
on the same cross wind which tends to cause the vessel
relative to the longitudinal center line of the vessel. They
to heel, to produce lift which acts through a moment
could also be tilted fore and aft so that the lift forces
1arm in the proper direction to overcome the heeling
will have forward components. The airfoil selection is
tendency of the vessel.
made to satisfy the criterion that the airfoil shall produce
Since we rely on aerodynamic moments to take the 65 lift when the wind direction is from the front to rear edge
place ‘of outboard stabilizing pontoons and/or the usual
of the airfoil orvice versa. Practically all aircraft air
practice of the sailor (or crew) leaning to the port or
foils satisfy this requirement, although not particularly
starboard side, our invention provides additional advan
e?iciently. An airfoil having symmetrical leading and
tages. We can rely on the same lift-producing feature
trailing portions (as shown or with a straight lower sur
to cause the vessel to be effectively lighter in the water. 70 face) is satisfactory. Assuming a reasonable lift coef?ci
ent and a comparatively large area, such as shown in
If the total weight of the vessel and crew is comparatively
FIGURE 2, and wind velocities of the order mentioned,
small, it is possible to obtain enough aerodynamic lift to
several hundred pounds of lift will be reasonably available.
This lift, operating through a moment arm of, for instance,
8 to 10 feet, will provide considerably more force to
attenuate or prevent heeling than is available by relying
on the usual crew-shifting methods. Furthermore, al
though not shown, we could use either biplane or tri
plane airfoil assemblies with or without stagger to some
what increase the total available aerodynamic lift.
Our airfoils 20 and 22 can be mounted as outriggers
keep the sailing vessel erect. The two forces can be
thought of as a mechanical couple tending to keep the
vessel righted, where the equal and opposite force to
de?ne the mechanical couple is caused by the cross wind
and sail.
It is understood that various changes and modi?cations
may be made in the invention without departing from the
protection of the following claims. For example, we be
lieve our invention to ‘be the ?rst method of at least at
by any of the methods disclosed in the referred-to prior 10 tenuating (when not fully preventing) heeling, which may
patents. In addition, we could use the deck of the vessel
be embodied in a form where the device is effectively used
as shown in FIGURE 2, by providing clamps 24 and 26
on one side only of the sailing vessel. Where there is
to which lateral support arms 28 are rigidly, removably
or hingedly ?xed. If a hinge connection is used there is
an outrigger pontoon on one side of the sailing vessel,
the weight of the pontoon must be relied on to limit
the advantage of beingr able to swing the airfoils vertically 15 heeling when the vessel heels in one direction, and its
up when they are not used, but the hinges would have to
buoyance must be relied upon when the vessel heels in
be locked when the airfoils are in the operative position
the opposite direction. With our system—-e.g. using air
(FIGURES 1 and 2). FIGURE 4 shows a further altem
foil 20 to the exclusion of airfoil 22, it is equally simple
ative where one of the arms 28a is attached by a clamp
to produce either negative or positive lift depending on
24a to the gunnel of the vessel. The kind of clamp 20 whether a clockwise or counter-clockwise tendency to heel
structure used for physical attachment of my device to
is to be overcome.
the vessel is not of particular consequence.
We claim:
Our airfoils could be rigidly attached to the outrigger
1. In a sailing vessel which has a sail for propulsion of
arms 28 after selection of a compromise angle of incidence
the vessel and a hull together with a mast supporting the
for the airfoils which would suit most purposes. However,
sail, the improvement comprising an aerodynamic lift
an advantage of our aerodynamic device over ordinary
producing device having a spanwise dimension larger
hydrodynamic outriggers is that the sailor can more
than the chordwise dimension, mechanical means at
closely approximate the sailing skill required as the sailor
shifts his weight during sailing. We achieve this aerody
namically by having the airfoils adjustable or by using
ailerons similar to conventional airplane ailerons. If
ailerons are used, their controls can be similar to the
controls shown in FIGURE 3.
In FIGURE 3 the airfoils 20 and 22 are shown rigidly
attached to spindles 30 and 32 whose ends are mounted in
bearings at the extremities of the outrigger arms 28.
Control arms 34 and 36 are ?xed to the spindles and have
cables or ropes 40 and 42 connected respectively to the
upper and lower ends of the respective control arms and
to a control stick 44. The control stick and cable assembly -‘
is the same as is used in a light aircraft for controlling the
Thus, the control stick 44 is mounted for
oscillation on a pivot 46 which is anchored in the cockpit
of the ‘boat.
The cables are crossed on one side of the
control stick only. Thus, when a control stick is moved
in one direction the airfoils will tilt clockwise and counter
clockwise respectively to achieve the conditions shown in
FIGURES 1 and 3. Thus, by changing the angle of incid
ence of the airfoils in the manner shown, magnitude of
the resulting vertical component of force as shown by the
vertical arrows in FIGURE 1 can be altered in accordance
with the desires of the sailor.
FIGURE 2 shows a modi?ed control arrangement Where
the control stick 44a is the same as the control stick 44.
taching the ends of said lift-producing device outboard of
the hull with the spanwise dimension of said device being
in a fore and aft relationship to said hull, the aerody~
namic force generated by said device and the mounting
thereof on the hull establishing a moment arm through
which the aerodynamic force acts on the hull, and said
aerodynamic device being responsive to cross winds for
producing said aerodynamic force to prevent heeling of
the vessel and thereby stabilizing the vessel.
2. The subject matter of claim 1 and means to ad
just the angle of incidence of said aerodynamic device by
tilting said device about a spanwise axis thereof.
3. In a sailing vessel having a hull, a mast secured to
the hull, and a sail attached to the mast, the improvement
comprising aerodynamic means for preventing the vessel
from heeling due to cross winds, said aerodynamic means
including a pair of outrigger airfoils, each airfoil having
a spanwise dimension greater than the chordwise dimen
sion, a pair of support arms for each airfoil, the inner ends
of each pair of arms attached to said hull, said pairs of
arms projecting laterally outward from the sides of said
hull, one airfoil connected to the outer ends of one pair
of arms, and the other airfoil connected to outer ends of
the other pair of arms, said airfoils being located at an
elevation with respect to said hull that they are in a plane
in the region of the lower part of said sail so that said
The difference in construction is that the airfoils 20 and
airfoils are exposed to cross winds which ordinarily cause
22 of FIGURE 2 are mounted on trunnions or on a
vessel heeling, and the aerodynamic forces generated by
said airfoils and acting through said pairs of arms being
spindle which is ?xed to the extremities of the outrigger
arms, 28. Thus, the airfoils are capable of being rotation
in a direction which opposes vessel heeling.
ally adjusted, which would necessitate attaching control
4. In a sailing vessel having a hull, a mast secured to
arms 36a and 34a to the airfoils themselves and not to 60 the hull, and a sail attached to the mast, the improvement
spindles such as at 30‘ and 32 in FIGURE 3. To obtain
comprising aerodynamic means for preventing the vessel
a reasonably large angular adjustment, slots 48 and 50
are provided in the airfoils so that there is clearance for
the cables.
An operating condition of our invention is shown in
from heeling due to cross winds, said aerodynamic means
including a pair of outrigger airfoils, each airfoil having
directions of the negative and positive lift forces of the
a spanwise dimension greater than the chordwise dimen
sion, a pair of support arms for each airfoil, the inner ends
of each pair of arms attached to said hull, said pairs of
arms projecting laterally outward from the sides of said
hull, one airfoil pivoted to the outer ends of one pair of
arms, and the other airfoil pivoted to the outer ends of the
other pair of arms, said airfoils being located at an eleva
tion with respect to said hull that they are in a plane in
the region of the lower part of said sail so that said air
foils are exposed to cross winds which ordinarily cause
respective airfoils are in the proper direction to tend to
vessel heeling, the aerodynamic forces generated by said
FIGURE 1 where the cross wind is represented by a num
ber of horizontal arrows. With the airfoils adjusted as
shown, there is a downward component of force (negative
lift) generated by airfoil 20. As the wind blows across
the deck of the vessel and across the airfoil 22, its angle of
incidence is such that airfoil 22 produces an upward
force (positive lift). Both of these forces act through
moment arms established by the support arms 28.
airfoils and acting through said pairs of arms being in 3,
direction which opposes vessel heeling, and controlmeans
including a single movably mounted control member with
connecting members attached thereto and to the respective
airfoils, said connecting members arranged to cause the 5
airfoils to pivot concurrently but in opposite directions in
response to movement of said control member.
References Cited in the ?le of this patent
Lachmann """"""" " Nov‘ 15' 1892
Germany ____________ __ May 4, 1953
France —————————————— —- Mar- 6, 1926
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