IMPROVEMENTS IN BOAT LOWERING APPARATUS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the Office
of the Commissioners of Patents on the 15th May 1878. A communication
from abroad by Martin Bourke, David M. Wilson, Benjamin John Morris,
Henry Bryson Shields, David S. Williams, Thomas Morris, and David Thompson
Harriott, all of Youngstown, in the County of Mahoning and State of Ohio,
United States of America.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Mid-
dlesex, Patent Agent. "IMPROVEMENTS IN BOAT LOWERING APPARATUS." [A
communication from abroad by Martin Bourke, David M. Wilson, Benjamin Johu
Morris, Henry Bryson Shields, David S. Williams, Thomas Morris, and David
Thompson Harriett, all of Youngstown, in the County of Mahoning and State of
Ohio, United States of America.]
The danger incurred by launching life and other boats, more especially during
storms or high seas, by lowering them directly alongside the ship, is obvious and
well known, and it is the object of the present Invention to avoid such danger by
providing an improved apparatus for launching boats at a distance from the ship's
side.
The boat is supported in and detachably connected to a frame, which is pendent
from pivots at the upper end of long bars that are in turn pivoted at their lower
ends to the side of the ship or other vessel above the water mark. The bars may
be lowered and raised by means of a windlass and ropes, the latter passing over
pulleys in vertical posts, which are fixed in the bulwarks, and extend above the
same.
The bars are stayed against any movement in the direction of the ship's longth
by ropes, wires, or rods, and while being lowered they are prevented from being
thrown back against the ship's side, thereby endangering the boat and her crew, by
means of locking bars which are pivoted directly behind the bars, and are connected
therewith by a hinged sliding block having flanges which enter lengthwise grooves
in the bars, and spring dogs or pawls that engage notches or teeth formed on the
upper side of said bars.

page_text: The teeth are so shaped that the dogs slide over them when the bars are being
lowered, but instantly bite and lock the bars when they begin to move in the
opposite direction, as they might sometimes tend to do when the ship rolls or
lurches.
The dogs may be caused to release their bite when it is desired to raise the bars,
after launching the boat, by any suitable means; for instance, cords may be
attached to them, and extended to the deck of the vessel, and there attached to a
lever.
The keel of the boat enters a slot or groove in the swinging frame, and loops or
eyes are attached to the ends of the boat to receive pins or studs fixed in the end
pieces of the swinging frame.
The boat is locked to the frame by means of a cross bar attached to a shaft which
projects through the bottom of the boat, and may hence be turned by the occupants
of the boat to bring the cross bar in line with the slot in the frame, which, being
done, the boat will detach itself from its fastenings, and float clear of the frame.
The windlass is located close alongside the bulwarks, and may be rotated by a
crank for raising the bars. To lower the bars, and thus launch the boat, I employ &
friction brake operated by a weighted lever.
The brake consists of a band applied to a smooth-faced pulley on the windlass
shaft, and attached to a lever, whose free end is connected with the weighted lever;
the free end of the latter works in a vertical guide, and may be locked by a trip
catch, to which a cord is attached.
The arm of the catch is made adjustable vertically by screwing it up or down on
the shank of the catch for the purpose. of adjusting the pressure of the friction band
on the pulley; this pressure requires to be graduated, according to the weight the
boat is to carry, for it is obvious that if the pressure were too slight the windlass
would rotate, the ropes unwind, the bars descend, and the boat be launched pre-
maturely.
A weight is applied to the lever, and made adjustable thereon, for the purpose of
graduating the friction of the brake while the boat is descending into the water,
thereby preventing too sudden descent.
To operate the apparatus the occupants of the boat, or any one stationed on the
deck of the vessel, as the case may be, pulls the rope of the catch, thereby trips the
catch, releases the weighted lever, and relieves the friction of the brake súfficiently
to allow the windlass to rotate slowly, thus unwinding the ropes and lowering the
arms with their attached boat-supporting frame.
The occupants may turn the shaft in the boat before or during the descent of
the boat, and thus leave the latter free to detach itself the instant it strikes the
water.
By the improved apparatus a boat may be safely launched at times when it would
be impracticable with the ordinary apparatus.
I propose to employ a covered boat, since it cannot be overloaded, and is for other
reasons much safer than an open one, but either kind may be used with equal
facility.
I propose in practice to protect the supporting bars from injury by contact of
the vessel with wharves or other structures by means of cleats or a box open on
the outer side.