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Патент USA US2125029

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‘July 26, l938.'
'
w. MEIENREIS
—
2,125,029
OAR
‘ Filed May 2, 1936
In Venfor:
2,125,029
Patented July 26, 1938
UNITED STATES PATENT * oFFicEj
2,125,029
OAR
Walther Meienreis, Berlin-Friedman, Germany
Application May 2, 1936, Serial No. 77,604
In Germany May 6, 1935
5 Claims.
(Cl. 9-—24)
When pulling an car through water, a pressure
zone will be produced on one side of the blade
and a suction zone on the other side thereof.
Both zones are of importance with regard to
along its upper edge with a streamline or other
wise suitably shaped lobe 3 the underside of which
curves downwardly into the blade. When using
the oar the water will rise up along the blade
in such a manner, that the formation of a hollow 5
5 the effect of the oar, since they produce resistance
is prevented. The lobe partially replaces
against the movement of the car blade through ’ space
the water on the suction side of the oar-blade
the water. The higher the resistance per unit and thereby prevents the car from dropping,
area the more favourable will be the rowing ef
which otherwise would take place on account
fect for the propulsion of the boat.
of the hollow space, and also prevents the for- 10
10
An car is generally moved through the water mation of the hollow space. In consequence
so that the upper or top-edge of the blade is thereof the water will flow off on the suction
approximately on a level with the surface of the side of the blade without forming an eddy effect
Water. It will then be seen that when moving so that the useful suction effect will not be de
the oar through the water, the surface of the creased. Thissuction effect, on the contrary, 15
15 water behind the blade (in the direction of the will be increased in View of the fact that on the
movement) will be lowered. A hollow space will suction side of the car there will be water only
be formed which, after the oar has been pulled
.
through, will be ?lled by an eddy. The'hollow and no hollow space.
What I claim is:—.
space and eddy must necessarily affect the effect
1. An oar comprising in combination a shank, 20
20 of the car and the prevention thereof conse
an oar-blade and means on the upper edge of the
quently results in improving the efficiency of the oar-blade for preventing the formation of a
car. In the case of the ordinary oar the effi
funnel-shapedhollow space and an eddy on the
ciency of the car will be lessened when the oars
suction side of the car when pulling the latter
man’s efforts are increased, because the hollow through the water.
25
25 space behind the car, will be enlarge-d. (In con
2. An oar comprising in combination a shank,
nection with a ship’s propeller the phenomenon an oar-blade and means on the upper edge of the
of so-called cavitation will be simultaneously ac
oar-blade for preventing the formation of a fun
companied by a sudden decrease in the e?iciency nel-shaped hollow space and an eddy on the
of the propeller.)
suction side of the oar when pulling the latter O3 0
30
It is an object of the present invention to obvi
through the water, the said means consisting of a
ate the formation of the hollow space and thus lobe on the suction side of the oar-blade.
also of the eddy resulting therefrom, by adding
3. An oar comprising in combination a shank,
a lobe to the suction side of the blade of the oar.
an oar-blade and means for preventing the for—
It is a further object of the invention to pro
35 vide an oar wherein the pressure side of the oar
blade is similar to that of an ordinary oar-blade,
while the suction side is provided with a lobe for
preventing the formation of a hollow space and
of an eddy on the suction side of the car when
40 pulling the latter through the water. According
to the invention the lobe is so arranged and
shaped that the cross-section of the oar-blade
resembles in shape a reversed L, one shank of
which is in a horizontal position and the other
45 shank of which is in a perpendicular position
when pulling the oar-blade through the water.
The present invention is illustrated, by way of
example in the accompanying drawing, in which
Fig. 1 represents a view of the rear of the
50 blade of the oar in elevation.‘
Fig. 2 shows a plan view of the car.
.
Figures 3 and 4_ are cross—sections of the oar
taken on lines III-III and IV-—IV of Figure 1.
In accordance with the present invention the
55 suction or rear side of the blade I is provided
mation of a funnel-shaped hollow space and an 35
eddy on the suction side of the oar when pulling
the latter through the Water, the said means con
sisting of a lobe on the suction side of the car
blade, said lobe being so- disposed and shaped
that the cross-section of the oar-blade resembles 40
in shape a reversed L, one shank of which being ,
in a horizontal position and the other shank in
a perpendicular position when pulling the oar
blade through the water.
4. An oar comprising in combination a shank,
an oar-blade and means for preventing the for
mation of a funnel-shaped hollow space and an
eddy on the suction side of the oar when pulling
the latter through the water, the said means
consisting of a lobe on the suction side of the
oar-blade, said lobe being so disposed and shaped
that the cross-section of the oar-blade resembles
in shape a reversed L, one shank of which being
in a horizontal position and the other shank in
a perpendicular position when pulling the oar
2
'
r
‘
2,125,029
blade through the water, the said horizontal
shank being of streamline shape and merging
into the perpendicular shank in a curve.
5. An oar comprising in ‘combination a shank,
an oar-blade and. means for preventing the for
mation of a funnel-shaped hollow space and an
eddy on the suction side of the oar when pulling
the latter through the Water, the said means
'consisting of a lobe on the suction side of the
oar-blade, said lobe being so disposed and shaped
that the cross-section of the oar-blade resembles
in shape a reversed L, one shank of which being
in a horizontal position and the other shank in
a perpendicular position when pulling the oar
blade through the Water, the said horizontal
shank being of streamline shape and merging 5
into the perpendicular shank in a curve and,
furthermore, the shanks of the reversed L taper
ing from the outer end of the oar-blade towards
the inner end ofrthe oar-blade.
10
WALTHER MEIENREIS.
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