IMPROVEMENTS IN AND RELATING TO THE CONSTRUCTION OF SHIPS OR VESSELS WITH TWIN PROPELLERS
Year: 1879

page_text: LETTERS PATENT to Henry Harris Lake, of the Firm of Haseltine, Lake,
SE
& Co., Patent Agents, Southampton Buildings, London, for the Invention of
IMPROVEMENTS IN AND RELATING TO THE CONSTRUCTION OF SHIPS OR
VESSELS WITH TWIN PROPELLERS." A communication from abroad by Zachariah
Oram, Doctor of Medicine, and Philip Brunner Grove, Hardware Merchant,
both of Philadelphia, Pennsylvania, United States of America.
PROVISIONAL SPECIFICATION left by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 27th December 1879.
HENRY HARRIS LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING TO THE
CONSTRUCTION OF SHIPS OR VESSELS WITH TWIN PROPELLERS." [A communi-
cation from abroad by Zachariah Oram, Doctor of Medicine, and Philip Brunner
Grove, Hardware Merchant, both of Philadelphia, Pennsylvania, United States of
America.]
This Invention relates to ships or vessels with screw propellers, and comprises
Beveral improvements hereinafter described.
To prevent the action of back water against the propeller, which occurs when
the latter is placed in the usual manner at the stern of the vessel, and produces
what is technically called "negative slip," causing the ship to move faster than the
screw is capable of propelling it, and the consequent dragging of the screw which
exhausts more than half the force of the engines or power employed, I employ twin
propellers, one at each side of the vessel in front of the midship and consequently
out of the reach of back water. Another object of this arrangement is to provide
what is technically called the "racing" of the screw, caused by the latter when placed
at the stern being thrown out of the water in riding over heavy waves. It is
impossible for the screw to leave the water under any conditions when placed in
front of the midships; hence the danger of the blades being broken by the sudden
force against the water in the descent of the stern to its normal position is entirely
prevented. For the purpose of drawing the water from the front end of the vessel
as much as practicable I arrange the shafts of the propellers parallel, or nearly so,
with the sides of that part of the vessel, employing night and left hand screws in
such a manner as to throw the water outwards from the kecl. And for the purpose

page_text: of causing a lifting of the bow in a sufficient degree to permit it to pass freely over
the water I arrange the shafts of the propellers on an upward angle from the latter,
so that the blades shall have such a downward pressure upon the water as to give
the desired lifting action.
In carrying the said Invention into practice I provide the propeller on the
starboard side with a left hand screw, and the one on the larboard side with a
right hand screw, so as to throw the water outward from the keel. The journals
on the front ends of the shafts have their bearings in a pedestal, and the journals
on the rear ends in stuffing boxes situated in blocks or brackets. The said pedestal
has flanges that are secured to the inside of the bottom of the vessel by means of
tapered bolts, which pass through the keel and are rivetted at their inner ends over
the flanges, which have curved countersunk holes, thus avoiding sharp corners at
each end of the bolts to prevent their being broken by sudden jars. The blocks or
brackets have flanges which are secured to the bottom and sides of the vessel by
means of bolts or rivets. For the purpose of producing a lifting of the bow of the
vessel sufficiently to cause it to pass freely over the water, and thereby facilitate
the speed of the vessel as much as possible, these shafts have an upward inclination
from their rear ends, whereby the blades of the propellers have a downward as
well as a backward pressure. The angle may be eighteen degrees, but I do not
contine myself to that angle, as a variation either way may be made as desired or
found by experiment to be most advisable. The shafts are on an angle from the
Jongitudinal central line of the vessel divergent from their front ends, so as to be
parallel or nearly so with the sides of the front end of the vessel to cause the pro-
pellers in their action upon the water to draw it away from the bow to give an
easy passage for the vessel.
The propeller shafts are provided with thrust blocks which have flanges rivetted
to the hull. The driving shaft is connected to the motive power, and is connected with
the propeller shafts by means of an intermediate shaft and a train of gear wheels.
The two wheels at the ends of the intermediate shaft may be movable on the said
shaft by means of a shifter, so as to be readily thrown in and out of gear with the
gear wheels on the propeller shafts to provide for disconnecting either propeller to
facilitate the turning of the vessel when desired.
In order to get the propellers as much under the sides of the vessel as practicable
they are located in recesses in the sides. These recesses are somewhat in the form
of a clam-shell, and have a gradual termination backwards to give a free passage
to the water as it is thrown outwards and backwards by the blades of the pro-
pellers. The aforesaid blocks or brackets may form the front sides of the recesses,
the remaining part being formed in the side plates. I contemplate however making
the whole of the recesses by a suitable shaping of the plates and connecting the
stuffing boxes with the latter. In this case the blocks or brackets may be dispensed
with.

page_text: Figure 15 & vervical songituum CIO on one, gure 1.
Figure 3 is a side elevation; and
Figure 4 is a front elevation of the same.
Figure 5 is a transverse section on the line 2,2, Figures 1 and 3.
Like letters indicate the same parts throughout the Drawing.
A represents the front end of a vessel which is provided with twin_screw-
propellers B, B, on the rear ends of the revolving shafts C, C, as shewn in Figures
3 and 6. The propeller on the starboard side has a left hand screw, and the one on
the larboard side a right hand screw, so as to throw the water outward from the
keel. The journals on the front ends of the shafts have their bearings in the
pedestal D, and the journals on the rear ends in the stuffing boxes E, E, situated in
the housings F, F. The said pedestal has flanges a, a, which are secured to the
inside of the bottom of the vessel by means of the tapered bolts b, b, passing through
the keel and rivetted at their inner ends over the flanges which have curved
countersunk holes, as shewn in Figure 2. Sharp corners are thereby avoided at
each end of the bolts to prevent their being broken by sudden jars. The housings

page_text: have flanges c which are secured to the bottom and sides of the vessel by means of
bolts or rivets. For the purpose of lifting the bow of the vessel sufficiently to
cause it to pass freely over or through the water, and thereby facilitate the speed
of the vessel as much as possible, these shafts have an upward inclination from
their rear ends, whereby the blades of the propellers have a downward as well as a
backward pressure. In the Drawing the angle is eighteen degrees, but I do not
confine myself to that angle, as a variation either way may be made as desired or
found by experiment to be most advisable. The shafts are arranged at an angle to
the longitudinal central line of the vessel, diverging from their front ends so as to
be parallel, or nearly so, with the sides of the front end of the vessel to cause the
propellers in their action upon the water to draw it away from the bow and give
an easy passage for the vessel.
The propeller-shafts C, C, are provided with thrust-blocks H, H, which have
flanges & rivetted to the hull; the caps of the thrust-blocks are omitted in the
Drawing. I is a driving shaft which is connected to the motive power, not shewn
in the Drawing. This shaft is connected with the propeller-shafts C, C, by means
of the intermediate shaft J and the train of gear-wheels K, K, K', K¹, and K, K².
The wheels K', K', may be movable on the shaft J by means of a shifter, so as to
be readily thrown in and out of gear with the wheels K, K, to provide for dis-
connecting either propeller to facilitate the turning of the vessel when desired.
In order that the propellers may occupy a position as much under the sides of
the vessel as practicable they are located in recesses L, one of which is shewn in
Figure 3. These recesses are somewhat in the form of a clam-shell, and have a
gradual termination backwards, as shewn in said Figure, to give a free passage to
the water as it is thrown outwards and backwards by the blades of the propellers.
The housings F, F, are represented in the Drawing as forming the front sides of
the recesses, the remaining part being formed in the side plates. I contemplate
however making the whole of the recesses by suitably shaping the plates and con-
necting the stuffing boxes E, E, with the latter. In this case the housings may be
dispensed with.
Having thus fully described the said Invention, as communicated to me by my
foreign correspondents, and the manner of performing the same, I wish it under-
stood that I claim,―
First. The combination of twin propellers with the sides of a vessel in front of
the midships, the said propellers having their shafts parallel, or nearly so, with the
sides contiguous to them, and having right and left hand blades for throwing the
water outwards from the keel, the said shafts either having or not having their
front ends elevated more or less from the horizontal line of the centre of the
propellers as desired, substantially in the manner and for the purpose set forth.
Second. The combination of twin propellers with the sides of a vessel in such a
manner that the propeller shafts are parallel, or nearly so, with the contiguous
sides of the vessel and at acute angles to the keel and to the main shaft, sub-
stantially as and for the purpose set forth.
Third. The combination of twin-propellers with the peculiar or "clam-shell"
shaped recesses in the sides of a vessel, the said recesses having a gradual back-
ward termination with the sides to give an easy outward and backward flow of
the water from the propellers, substantially as above set forth.
In witness whereof, I, the said Henry Harris Lake, have hereunto set my
hand and seal, this Twenty-first day of June, in the year of our Lord One
thousand eight hundred and eighty.