IMPROVEMENTS IN APPARATUS FOR LOWERING AND DETACHING SHIPS' BOATS, PARTLY APPLICABLE FOR OTHER PURPOSES
Year: 1878

page_text: LETTERS PATENT to Alexander Melville Clark, of Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR LOWERING AND DETACHING SHIPS' BOATS, PARTLY APPLICABLE
FOR OTHER PURPOSES." A communication from abroad by William Alexander
Brice, of Paris, France.
Sealed the 10th January 1879, and dated the 16th July 1878.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 16th July 1878.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN APPARATUS FOR LOWERING AND DETACHING
SHIPS' BOATS, PARTLY APPLICABLE FOR OTHER PURPOSES." [A communication
from abroad by William Alexander Brice, of Paris, France.]
This Invention relates to apparatus for lowering and detaching ships' boats, and
consists, first, in improved ball-and-link attachments, combined with a system of
controlling gear, by means of which the boat may be detached with perfect safety,
either automatically or by hand.
The controlling gear consists of chains or ropes connecting the bar-and-link
attachments at the bow and stern of the boat in such manner as to bring thein both
under the control of a single releasing lever, and prevent either becoming discon-
nected without the other when the boat is lifted at one end only. This releasing
lever is controlled by a spring bolt, which may either be made to release itself when
it is desired that the boat should be detached automatically, or which may be
released by hand when the boat is placed under the control of one man, and is to be
dropped on to the water from a height.
The Invention consists, secondly, in an automatic brake applied to the "falls" of
the boat lowering tackle for controlling the descent of the boat, the said brake being
also applicable for controlling the passage of cords or chains used for lowering
weights and other similar purposes.

page_text: The ball-and-link attachments at the bow and stern of the boat being exactly
alike, it will be sufficient to describe one of them only. They consist of a ball
about 4 or 6 inches in diameter, provided with a stem, which is attached to a short
length of chain connected to the lower block of the davit tackle, and a link or
shackle of wrought iron or steel having at the lower part a loop or eye large enough
to admit the ball, the two sides of the link being brought so close together at the
upper part as only to admit the shank between them.
The two sides of the link are rather closer together towards their upper part than
the diameter of the said shank, so that when the ball is passed through the loop of
the link and the shank slid up the narrow part, the sides of the link will be slightly
forced apart until the shank arrives at its highest position, where the width of the
link corresponds to the diameter of the shank. The narrow part of the link closes
slightly behind the shank, and thus prevents the ball falling out of the link when
the tackle becomes slack by that end of the boat being lifted by a wave.
The link is also curved forward at the upper part to embrace the ball, and the
ends of the shackle or link are pivoted on a horizontal bolt upon which the link is
free to turn over in order to release the ball, which however it is prevented from
doing until the proper moment. To this bolt is also attached a U shaped link, which
is connected by a chain to the keel of the boat.
The links are prevented from turning over by chains connected thereto, and
passing down through thimbles or eyes at the bottom of the boat, thence through
similar thimbles or eyes under the thwarts and along the sides of the boat.
The one chain terminates in a thimble through which the other chain passes, and
is then doubled back and attached to a hook on the releasing lever before referred
to. This lever is mounted on a pivot at one end, and the tension of the chains
caused by the weight of the boat on the links tends to raise the lever in a vertical
direction. This however it is prevented from doing by a bolt or other device for
locking the lever.
A suitable arrangement, capable of operating automatically or of being released
by hand, consists in a bolt working in guides on the lever, upon which bolt is a
spiral spring confined between one of the guides and a collar on the bolt, which
spring tends to push the bolt in a horizontal direction. This bolt is provided with
a handle, and when in its locked position it is received in a hook-shaped staple fixed
to the thwart or other fixed part of the boat, the staple being of this form in order
to allow the handle to pass it and be turned back behind it, in order to lock the
bolt and prevent it being released until the boat is about to be lowered. When the
boat is to be lowered the bolt is turned, and the bolt is then free to be automatically
pushed out of the staple by the pressure of the spring immediately the upward
pressure of the bolt against the staple ceases, and not before, this upward pressure
only ceasing when the tension on both the chains is relieved by the boat becoming
waterborne. When this occurs the bolt is released from the staple, and immediately
the slightest strain comes again on the chains by the rise and fall of the waves, the
lever is raised until the chain is detached from the hook on the releasing lever,
whereby both links are allowed to turn over simultaneously and the balls are released
therefrom, the boat being then entirely detached.
Instead of the bolt being released automatically it may be pushed back by hand
if it is desired to release the boat before it reaches the water and allow it to drop in
to the water from a height, but if it desired not to place the boat thus under the
control of one man, the part of the bolt which enters the staple may be roughened
so as to prevent the bolt being pushed out of the staple by hand, so long as the
strain caused by the weight of the boat is upon it.
In order to prevent either end of the boat being detached when the boat is lifted
by a wave at one end only, I provide two stops on the chains just in front of the
thimbles, so that when one end of the boat is lifted, the chains are prevented from
becoming slack, and the link at the other end (on which there is still the strain
caused by the weight of the boat at that end) is prevented from turning over and
releasing its ball.

page_text: The link at that end of the boat which is lifted does not tend to turn over, inas-
much as there is then no strain upon it, and the narrowed part of the link prevents
the ball slipping down to the eye of the link when there is no strain upon the chain
tending to turn the link over and pull the ball out of the link.
The improved brake is actuated by the strain on the rope or ropes to which it is
applied, and it consists of a lever pivoted in a frame, which is also pivoted in a
stirrup piece, the short arm of this lever acting as a jaw to grip the falls of the
tackle or other rope or ropes to which the brake is applied, and which pass between
it and a single or double grooved sheave mounted between the plates of the frame,
the surface of the jaw being curved to correspond to said sheave slightly grooved to
receive the rope and roughened if necessary.
The falls or other ropes, after passing the sheaves, pass over a single grooved sheave
mounted loose in a slot in the long arm of the lever, and thence under another single
grooved sheave mounted in the other end of the frame through eyes in the end of a
stirrup piece to the davits.
The stirrup piece may be fixed or retained in any suitable position against the
rail of the ship or otherwise.
The sheave on the lever is not in a line with the other sheaves, the result of
which is that the strain on the ropes tends to oscillate the lever and press the jaw
against the sheave, this pressure being greater, the greater the strain on the ropes,
so that the brake is automatically applied.
To release the brake a cord is attached to the extremity of the lever, by pulling on
which the effect produced by the strain of the rope is overcome, and the pressure of
the jaw is partially or entirely relieved as required.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
16th January 1879.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN APPARATUS FOR LOWERING AND DETACHING
SHIPS BOATS, PARTLY APPLICABLE FOR OTHER PURPOSES." A communication_
from abroad by William Alexander Brice, of Paris, France.
This Invention relates to apparatus for lowering and detaching ships' boats, and
consists first in improved ball-and-link attachments combined with a system of
controlling gear, by means of which the boat may be detached with perfect safety,
either automatically on being waterborne, or forcibly by hand before being water-
borne, notwithstanding the strain on the tackle, or it may be disengaged when
waterborne by lifting the ring off the lever hook hereafter described, even when the
hook is securely fastened down.
The ball-and-link attachments are an improvement on the same form of attach-
ment described in the Specification of Letters Patent granted to Benjamin Franklin
Stevens, dated June 26th, 1872, No. 1932. In common therewith they possess the
advantages of being simple, and perfectly certain and reliable in their action, and of
acting as swivels so that no separate swivel is required, and that the balls present
no projections liable to foul the tackle or catch the clothes of the men in the boat.
The controlling gear consists of chains or ropes connecting the ball-and-link
attachments at the bow and stern of the boat in such manner as to bring them both
under the control of a single releasing lever and prevent either becoming discon-
nected without the other when the boat is lifted at one end only. This releasing
lever is controlled by a spring bolt, which may either be made to release itself when
it is desired that the boat should be detached automatically, or which may be
released by hand when the boat is placed under the control of one man and is to
be dropped on to the water from a height.
The Invention consists, secondly, in an automatic brake applied to the "falls" of
the boat lowering tackle for controlling the descent of the boat, the said brake being
also applicable to other tackle used in lowering heavy bodies generally, and for
holding the rope taut instead of fastening it each time when slack has been over-
hauled, as for engineering purposes, and in all other cases in which a self-acting
brake can be used for controlling the passage of a rope or ropes.
In order that the Invention may be more readily understood I have illustrated
it in the accompanying Drawings, and will proceed to describe it with reference
thereto.
Figure 1 is a longitudinal section of a ship's boat fitted with the apparatus of
this Invention, and Figure 2 is a plan of the same.
Figure 3 is a front view of one of the ball-and-link attachments on a larger scale;
Figure 4 is a vertical section; and Figure 5, a top view of the same.
Figure 6 shows the same in the act of releasing the ball; Figure 7 is a detail;
Figure 8, a side view; and Figure 9, a cross section of the releasing lever and its
spring bolt.
The same letters of reference indicate the same parts in all the Figures.
The ball-and-link attachments at the bow and stern of the boat each consist
of a hollow ball A, about four or six inches in diameter, provided with a stem a
attached to a short length of chain A¹ connected to the lower block of the
davit tackle. B is a link or shackle of wrought iron or steel, having at the lower
part a loop or eye large enough to admit the ball A, the two sides of the link being
brought so close together at the upper part as only to admit the shank a between
them.
The two sides of the link are rather closer together at b than the diameter of the
said shank, so that when the ball is passed through the loop of the link (as shown

page_text: in dotted lines, Figure 4), and the shank slid up the narrow part of the link, the
sides of the latter will be slightly forced apart until the shank arrives at its highest
position (shown in full lines, Figure 4) where the width of the link corresponds to
the diameter of the shank. The narrow part b of the link closes slightly behind
the shank, and thus prevents the ball falling out of the link when the tackle
becomes slack by that end of the boat being lifted by a wave; and this it is
which constitutes the improvement on the same attachment described in the before-
inentioned Patent, No. 1932, 1872, as I am thereby enabled to dispense with the
use of the counterbalanced levers or tumblers therein described; and by the
improved method of attaching the hooks I am independent of the boat stem and
fixtures, and can thus use canting or steadying side lines, thus having my point of
suspension high above the centre of gravity of the boat, a very important point
not obtainable in the above-mentioned Patent.
The link B is also curved forward at the upper part to embrace the ball A, as
shown, and the ends of the shackle or link B are pivoted on a horizontal bolt C,
upon which the link B is free to turn over to the position shown in Figure 6, in
order to release the ball which, however, it is prevented from doing until the proper
moment. To this bolt C is also attached a U shaped link D which is connected by
a chain E to the keel of the boat. .
The links B are prevented from turning over by chains F, F', connected to
links B passing down through thimbles or eyes fat the bottom of the boat, thence
through similar thimbles or eyes f¹ under the thwarts and along the sides of the
boat, as shown, or where most convenient.
The one chain F terminates in a thimble f, through which the other chain F¹
passes, and is then doubled back and attached to a hook on the releasing lever G.
This lever is pivoted at G', and the tension of the chains F, F', caused by the
weight of the boat on the links B tends to raise the lever in the direction of the
arrow 1, Figure 8. This, however, it is prevented from doing by a suitable bolt or
other device for locking the lever.
A convenient arrangement, capable of operating automatically or of being released
by hand, is shown in Figures 8 and 9, in which g is the bolt working in guides g¹, g²,
on the lever G. Upon this bolt is a spiral spring / confined between the guide g²
and a collar on the bolt, which spring tends to push the bolt in the direction of
arrow No. 2. If the use of a spring is objectionable, the same movement may be
obtained by a weight and cord passing over a pulley. This bolt is provided with a
handle g³, and when in its locked position it is received in a hooked-shaped staple i
fixed to the thwart or other fixed part of the boat; the staple i being of this form
in order to allow the handle g³ to pass it and be turned. back behind it, as shown in
full lines, Figure 9, in order to lock the bolt and prevent it being released until the
boat is about to be lowered. The bolt is then turned until handle g³ is in the dotted
position, Figure 9, and the bolt is then free to be automatically pushed out of the
staple by the pressure of spring h or the pull of the rope as aforesaid, immediately
the upward pressure of the bolt against the staple i ceases and not before, this
upward pressure only ceasing when the tension on the chains F, F¹, is relieved by
the boat becoming waterborne. When this occurs the bolt is released from staple i,
and immediately the slightest strain comes again on the chains F, F¹, by the rise and
fall of the wave, the lever G is raised until chain F₁ is detached from the hook,
whereby both links are allowed to turn over simultaneously and the balls A are
released therefrom, the boat being then entirely detached.
Instead of bolt g being released automatically, it may be pushed back by hand if
it is desired to release the boat before it reaches the water, and to allow it to drop
on to the water from a height; but if it is desired not to place the boat thus under
the control of one man, the part of the bolt which enters the staple i may bé
roughened, as shown, so as to prevent the bolt being pushed out of the staple by
hand so long as the strain caused by the weight of the boat is upon it.
In order to prevent either end of the boat being detached when the boat is lifted
by a wave at one end only, I provide two stops k on the chains F, F¹, just in front

page_text: of the thimbles f, as shown more clearly in the detail view, Figure 7, so that when
one end of the boat is lifted the chains F, F', are prevented from becoming slack,
and the link B at the other end (on which there is still the strain caused by the
weight of the boat at that end) is prevented from turning over and releasing its
ball A.
The link B at that end of the boat which is lifted does not tend to turn over,
inasmuch as there is then no strain upon it, and the narrowed part 6 of the link
prevents the ball slipping down to the eye of the link when there is no strain upon
the chain A' tending to turn the link over, and pull the ball out of the link.
Instead of, and preferably to, the hinged spring bolt lever G, which might be
objected to as subject to derangement, I would use for the same purpose an arrange-
ment shown in Figures 10, 11, and 12, consisting of a link B' of similar construction
to those B in the bow and stern, and acting on the same principle; but in this case
the end of the bow chain F, instead of terminating in a thimble ƒ2, would terminate
with a ball and shank A, and the other chain F', instead of doubling back, as
aforesaid, would terminate with, first, a strong spiral spring L attached to the
shackle D', whilst the link B' would be attached by a chain and common hook s to
a staple on the side of the boat, so as to be detached at pleasure, and allow the
hook B¹ to be turned over to release the ball A', and so free both of the releasing
chains F and F', as before. Z is a safety rope substituted for the stop k on the bow
chain F.
When the bow of the boat is securely hooked and suspended, and the safety
rope Z not yet secured, and the chains F and F¹ connected by means of the ball-
and-link arrangement, the stern can be hooked on in perfect safety, but it becomes
impossible to suspend the boat at the stern unless and until the bow is properly
secured and suspended, as there being now no stop to the bow chain F, the slack
of the chain F pulled by the strain of the chain F³, produced not only by the sus-
pension at the stern, but also by the afore-mentioned spiral spring, would pull the
link B¹ into the releasing position. Likewise when the strain on chain is taken
off by the bow of the boat being lifted, the same action would occur, and the release
would take place. Similarly, when the boat is completely lifted, and strains from
suspension entirely taken off, the strain from the spiral spring, or a pull with the
hand between the stop k on the stern chain F' and the link B¹, would bring the
said link into the releasing position.
Finally, when the rope Z is secured to a fixed point on the boat or thwart at rear
of B' after the boat is securely suspended at both ends, nothing can cause the
release of the chains F and F¹, and consequently the detachment of the boat, except
by unhooking the chain and hooks from the staple t, and allowing the link B¹ to
turn over, in which case chains F and F¹ are each released, rope Z being no obstacle,
as it follows the same direction as chain F, and the detachment is effected at bow
and stern, notwithstanding the strain and the safety rope Z; but if hook 8 be
padlocked to staple t, detachment can only take place automatically on the boat
being lifted, which can be prevented till necessary by the safety rope Z.
Figure 13 is a side view; Figure 14, a longitudinal section; and Figure 15, a top
view of the improved brake to be applied to the falls of the davit tackle to control
the descent of the ship's boat or other heavy body. This brake is actuated by the
strain on the rope or ropes to which it is applied, and it consists of a lever
working on a pin in a frame m, which is also pivoted in a shackle n. m³ is a
sheave having one, two, or more grooves, corresponding to the number of ropes the
brake is intended to control. It is mounted to rotate freely between the plates of
the frame m, near one end thereof. The short arm of lever is formed with a
jaw 2, which bears against the sheave m¹, is curved to correspond thereto,
roughened, and slightly grooved to receive the rope or ropes, and avoid flattening
them too much.
The falls o or other part of the tackle to be controlled by the brake pass between
the jaw and the sheave m', and are forcibly gripped by the former against the
latter, the grip becoming stronger as the tension on the ropes is greater, this result

page_text: being produced by the ropes acting on the lever as follows:-The long arm of said
lever is slotted, and a sheave p is mounted therein, over which the falls or other
ropes pass from the sheave m¹, and thence under another sheave 9 mounted in the
frame m at the opposite side of the lever axis to the sheave m¹, and about in line
with and m¹. The ropes pass thence through an eye or eyes to the davit head
or other blocks.
The shackle n may be fixed or retained in any suitable position attached to a
fixed hook, ring, or support, to prevent the brake being carried along by the ropes
as they run out.
The sheave p is preferably of a square, hexagonal, or other polygonal forn, so as
to present a number of salient angles around its periphery, to prevent either of the
ropes (in the case of two or more) slipping upon it independently of the others,
and ensure the ropes being payed out simultaneously and equally when the pressure
of the jaw is relaxed, even should the strains on the ropes be unequal.
The sheaves p and q may have separate grooves, one for each rope, or a single
groove only, or they may not be grooved at all.
The lever being bent, the ropes in passing over the sheave p are diverted from
the straight line between the sheaves m' and q, the result of which is that the strain
on the rope or ropes tends to oscillate lever l, and press the jaw 12 forcibly against
the sheave m¹, the pressure being greater the greater the strain.
To release the brake a cord is attached to the extremity of the lever l, as shown,
by pulling on which the effect of the strain on the tackle is overcome, and the
pressure of the jaw l partially or wholly relieved, as required.
I would observe that although m¹, p, and q are described as sheaves, they might
be simply fixed cross pins or their equivalent, but sheaves are preferable to avoid
chafing the ropes.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is,-
1st. The improvement in the ball-and-link attachment, herein shown and described,
whereby the ball is prevented from falling out of the link when the tackle becomes
slack, and the point of suspension of the releasing hooks made independent of the
boat fixtures.
2nd. The combination with the said ball-and-link attachments at the two ends of
a boat of the arrangement of ropes or chains F, F1, provided with stops k, and of.
the releasing lever G and spring bolt (or, in lieu of the spring bolt and lever, the
releasing link-and-ball arrangement shown in Figures 10, 11, 12), arranged and
operating substantially as shown and described.
3rd. The improved automatic brake, constructed and operating substantially as
and for the purpose specified.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set my
hand and seal, this Fifteenth day of January, in the year of our Lord One
thousand eight hundred and seventy-nine.
A. M. CLARK. (L.S.)