AN IMPROVED ARRANGEMENT OF SCREW PROPELLERS FOR VESSELS
Year: 1884

page_text: CLNT LEIE DIEVIT.
I ELIAS SILL HAWLEY of Buffalo in the County of Erle and State of New
York, United States of America, Attorney-at-Law do hereby declare the nature
of my Invention for AN IMPROVED ARRANGEMENT OF SCREW PROPELLERS FOR
VESSELS and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The object of my Invention is to increase the speed and power of that class of
vessels, which are propelled by screw-power, and to that end it consists in a
peculiar arrangement of screws by means of which the combined working area of
the screws is substantially equal to or somewhat greater than the maximum
immersed transverse section of the vessel.
This I accomplish by placing two screws in the line of the keel, one at the bow
and the other at the stern, both located in the dead-wood, the bow and stern being
of like tapering configuration, and in addition to these I place twin screws at each
end of the vessel, located along the tapering portions of the bow and stern,
These six screws are to be made of such size that their combined working area is
about equal to or preferably somewhat greater than the maximum immersed
transverse section of the vessel.
My Invention further consists in having the shafts, by which the twin-screws are
rotated, slightly inclined in an upward direction, so that the twin-screws at the bow
have a lifting tendency, while those at the stern have a contrary or depressing
tendency, thereby lessening the amount of water to be displaced by decreasing the
area of the submerged cross-section at the bow.
My Invention further consists. in having the shafts of the twin-screws converge
towards the bow and stern, thereby having the effect at the bow of causing the
impinging water on both sides to assume a direction substantially parallel to
the tapering sides, and consequently effecting a reduction of friction, while at
the stern the water is thrown inwardly and upwardly, having a tendency to
restore the displaced water to its normal level, and increase the effectiveness of the
rear screw.
My Invention further consists of other details of construction, which will be
more fully hereinafter described and pointed out in the claims,
In the Drawings
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"
Figure 1 is a top plan view of the hull of a vessel, embodying my improvements,
Figure 2 is a bottom plan view of the same.
Figures 3 and 4 are respectively side and end elevations of the same.
Figure 5.is an end elevation of the vessel with the screws removed, and
Figures 6 and 7 are different detached views of the sheath for the projecting ends
of the shafta..
. .i

page_text: .
Referring to the Drawings
a is the hull of the vessel; b the bow, and c the stern, Both the bow and stern
are the same in configuration, and are preferably made very sharp as clearly shown
in the Drawings.
are the two screws which are located in the dead-wood in the line of the
keel, and between them and the extreme ends of the hull are the balanced
rudders c e¹.
The screws are each revolved by the separate shafts ƒfƒ¹ respectively, cach
Bhaft having a separate engine as shown at f¹ Figure 1.
gg are the twin-screws at the bow, and g¹ g' are the twin screws at the stern.
These screws are each operated by separate shafts g² and engines g' as clearly shown
in Figure 1.
By the arrangement just described, I have six screws operating to propel the
vessel, three in the bow, and three in the stern, each having its separate and
independent motive power, and my design is to construct these six screws of such
size that their combined working area is substantially equal to or preferably
somewhat greater than the maximum submerged transverse section of the vessel
which I have represented, for example, in Figure 4, in which all that portion of tho
hull of the vessel below the line ✗-X represents the maximum submerged
portion. The immense force exerted by the combined action of the six screws is
productive of a correspondingly increased resistance from the displaced water, and
in order to decrease this resistance as mucli as possible, I have secured the shafts
operating the twin-screws g g at the bow, in a direction inclining upwardly from a
horizontal plane, as clearly shown in Figure 3, the ends of the shafts at which tho
screws are located being the highest so that these twin-screws at the bow have,
while the vessel is moving forward, a lifting tendency. The shafts operating the
twin-screws g g' at the stern are secured in a similar position with relation to the
stern, and have, while the vessel is moving forward, a depressing tendency which
serves to assist the lifting tendency of the twin-screws g g at the bow, thus enabling
the vessel to present a diminished transverse immersed section, thereby producing
a decrease in the resistance caused by the displacement of the water.
In addition to the inclination of the shafts operating the twin-scrows in tho
bow just described, I have placed them so that they converge towards the bow, as
clearly shown in Figures 1 and 2, thereby having the effect of causing the impinging
water thrown back to assume a direction substantially parallel to the tapering sides
of the bow, and consequently effecting a reduction of friction and resistance caused
by the impacting water.
The shafts operating the twin-screws g' g¹ are secured in a similar position with
relation to the stern, and in such position the screws operated by them have a
tendency to throw the water inwardly and upwardly, having the effect of restoring
the displaced water to its normal level and increase the effectiveness of the roar
scrow.
The shafts g' operating the twin-screws project some distance beyond the tapering
sides of the bow and stern so as to give the requisite space for the operation of the
screws. The exposed portions of these shafts are protected in a manner which is a
clearly shown in Figures 5 and 6, in which h is the circular sheath, which enclosos
the shaft having the projecting portion h³, extending substantially in a.horizontal
direction to the tapering side of the vessel. This sheath and its projecting
portion or extension his firmly riveted to the side of the vessel, along its
contacting edges, and the edge h³ of the extension h' is made somewhat sharp so t
as to cut the water and throw it off above and below the portion h¹ with the least
possible friction.
My improved mode of propulsion enables me to move the vessel equally well in
either direction, and the several scrows being provided with separate engines can
be used in concert or not, as occasion demands, and by a proper manipulation they i
can be employed in turning the vessel ospecially when in the trough of the sea, ">

page_text: While I prefer to provide each screw with a separate engine, other provision
could equally well be made, as for instance, the three forward screws could be
operated by a single engine, and the three in the stern in the same manner, or if
found desirable one or more additional engines could be connected to each separato
shaft. I have provided the vessel, as shown, with two rudders, one at each end,
and while both could be used simultaneously in changing the direction of the vessel,
it would perhaps be preferable to cause the forward rudder to remain idle, and
to depend alone upon the one in the rear, for the reason that the forward rudder, if
operated while the vessel is moving quickly, would have a prejudicial effect upon
the ɛcrew immediately in its rear,
The fact that my vessel by reason of its peculiar construction can be propelled
with great power and efficiency in either direction makes it extremely valuable
when employed as a ram for war purposes. In this case the end of the vessel
could be provided with sharp prows, and could be propelled against an enemy's
vessel with great destructive effect and quickly disengaged from such vessel after
the delivery of the blow, and drawn back out of the way.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declaro that what
I claim is
First. A vessel having its bow and stern of like tapering configuration, and being
provided with three propeller-screws at each end, one screw being located in the
dead-wood in the line of the keel, and the other two being twin-screws, all located
substantially as shown, the six screws having their combined working area at least
equal to or somewhat greater than the maximum immersed transverse section of
the vessel, substantially as shown and described.
Second. A vessel having its bow and stern of like tapering configuration and
provided with twin-screws in both bow and stern, the shafts of which are inclined
in an upward direction, substantially as shown, and for the purpose stated.
Third. A vessel having its bow and stern of like tapering configuration, and
provided with twin-screws in both bow and stern the shafts of which are inclined
in an upward direction, and converge towards the bow and stern, substantially as
shown and for the purpose stated.
Fourth. The sheath for the protruding ends of the shafts of the twin-screws g g,
g'g', consisting of the cylindrical portion h, and the extension h¹, having the sharp
edge between the end of the shaft and the side of the vessel, substantially as
shown and described.
Dated this 3rd day of June 1884.