Apparatus for Lowering and Raising Ships' Boats.
Year: 1895

page_text: Date of Application, 10th Dec., 1895
Complete Specification Left, 9th Sept., 1896-Accepted. 5th Dec., 1896
TRUVIDIONAL SPECIFICATION.
Apparatus for Lowering and Raising Ships' Boats.
I, BRADFORD LESLIE, K.C.I.E. of 6, Florence Terrace, Falmouth, in the
County of Cornwall, Civil Engineer, do hereby declare the nature of this invention
to be as follows :-
My invention relates to apparatus for lowering a ship's boat into the water and
raising it therefrom, the whole operation of lowering or raising being performed
by a rope or chain worked by any suitable power.
For this purpose, I provide on the ship's side a vertical guide in which can slide
a block carrying a pivot for the lower end of a davit so shaped that part of it
curves inwards over the deck of the vessel. The upper part of the davit above
this inwardly curved part carries a curved cradle which forms a concave track for
the rollers of a lorry. There are two of the davits, suitably braced together, the
two lorries of which carry the boat above the deck, the davits being held in
upright positions by the rope or chain. When it is desired to lower the boat, the
rope or chain is slacked out allowing the davits to descend they being at the same
time caused to turn outwards upon the pivots at their lower ends by their inwardly
curved parts bearing against guide rollers on deck. When their pivots reach stops
at the lower ends of their vertical guides the farther slacking out of the rope or
chain allows the davits to swing outwards and downwards on their pivots until they
are immersed in the water. During this movement of the davits the lorries
carrying the boat travel along their curved tracks, always towards the lowest
parts of the tracks, the boat thus retaining its proper position for floating when it
reaches the water.
When the boat is floated away, the davits can again be drawn up by the
rope or chain.
•
When the boat has to be raised, the davits are lowered till the lorries are
submerged, the boat is then floated to position over the lorries, and the davits
are drawn upwards and inwards by hauling up the rope or chain, thus raising
the boat to its position above the deck. In order to provide for raising the boat
when the sea may be too rough to allow of its being raised in the manner
described, 1 make the cradle which forms the curved track for the lorry not a
fixed part of the davit, but a separate frame having its middle pivotted to the top
end of the davit, and its lower end, when it is in normal position, secured by a pin,
bolt or other catch to the inwardly projecting part of the davit.
In rough
weather I release this catch and turn the cradle on its pivot so as to project
outside the davit and rest against its back, in which position it is held by an
approximately horizontal guy rope and forms, as it were, the jib of a crane.
The boat is raised, by tackles hanging from the pair of jibs. When the boat
has attained a certain height the davits are, lowered, and as they are caused to
move outwards by their curved sides bearing against the guide rollers, the cradles
being held by the guy ropes are caused to turn on their pivots bringing the lorries
under the boat, which is lowered to rest on them and the cradles finally resume
their normal position on the davits which are then raised bringing the boat upwards
and inwards to its position above the deck.
Dated this 10th day of December 1895.
ABEL & IMRAY.
Agents for the Applicaut,

page_text: 333337
I, BRADFORD LESLIE, K.C.I.E. of 6 Florence Terrace, Falmouth, in the
County of Cornwall, Civil Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
My invention relates to apparatus for lowering a ship's boat into the water and
raising it therefrom, the whole operation of lowering or raising being performed by
a rope or chain worked by any suitable power.
For this purpose, I provide on the ship's side a vertical guide in which can slide a
block carrying a pivot for the lower end of a davit so shaped that part of it
curves inwards over the deck of the vessel. The upper part of the davit above
this inwardly curved part carries a curved cradle which forms a concave track for
the rollers of a lorry.
There are two of the davits, suitably braced together, the two lorries of which
carry the boat above the deck, the davits being held in upright positions by the
rope or chain.
When it is desired to lower the boat, the rope or chain is slacked
out allowing the davits to descend they being at the same time caused to turn
outwards upon the pivots at their lower ends by their inwardly curved parts
bearing against guide rollers on deck.
When their pivots reach stops at the lower ends of the vertical guides the
farther slacking out of the rope or chain allows the davits to swing outwards and
downwards on their pivots, until they are immersed in the water. During this
movement of the davits the lorries carrying the boat travel along their curved
tracks always towards the lowest parts of the tracks, the boat thus retaining its
proper position for floating when it reaches the water. When the boat is floated
away, the davits can again be drawn up by the rope or chain. When the boat has
to be raised, the davits are lowered till the lorries are submerged, the boat is then
floated to position over the lorries, and the davits are drawn upwards and inwards
by hauling up the rope or chain, thus raising the boat to its position above the
'deck.
The accompanying drawings shew the construction which I prefer to employ in
carrying out my above described invention.
Figure 1 shews a part cross section of a ship with a side view of the davits
connected thereto and shewing the various positions which these are made to
assume in the operation of raising or lowering a boat.
Figure 2 shews a similar view, with the cradle of the davit in the inverted
position for raising the boat in rough weather.
Figures 3, 4, 5 and 6 shew respectively enlarged front view, side view, and cross
sections of part of the guide bars and sliding blocks on the ship's side, by means
of which the davits are enabled to slide up and down;
Figure 7 shews a front view of the two davits with their guides when in the
raised position supporting a boat.
Figure 8 shews a cross section of the cradle and end view of the lorry and
Figure 9 a part side view of one end of the cradle with the lorry.
Figure 10 shews the section through the grooved pulley and hauling rope and
the attachment of the latter to the davit for raising and lowering this.
The lower end of the davit A is pivotted to a sliding block B, which can slide
up and down between the guide bars C that, are fixed to the skin D of the ship.
The davits A are preferably made of a strong but light triangular lattice-like
structure built up of flat bars as shewn at Figures 1, 4, 6, 8 and 10; when in the
fully raised position A' Figure 1, its outer side is approximately vertical, while the

page_text: curved inner side projects inward over the deck. At its upper outer angle it has
pivotted to it the cradle E preferably of open lattice work of suitable curved form
which cradle when in the position shewn at Figures 1 and 9, rests with its lower
part upon the correspondingly curved upper surface of the davit and is secured in
that position by suitable holding bolts or catches. On the cradle is mounted the
lorry F having bolsters F adapted to fit against the sides of the boat, and running
on wheels G that fit with slight clearance between the top and bottom flanges of
the cradle E the ends of which are closed as shewn, so that the lorry is always
retained on the cradle; it is so formed as to project inwards beyond the cradle when
the davit is in the fully raised position as at A' Figure 1, so that the boat, carried
thereby is almost completely inboard.
When in this position, the curved inner face of the davit bears against the deeply
grooved pulley H round which the steel wire rope I is spirally coiled, the looped
end thereof being secured to the looped bolt J fixed on the inner face of the davit,
as at Figure 10, so that when the rope is coiled up it holds the davit securely in
this position, the davit being farther secured by a stay rope from the upper end of
the cradle if necessary.
When it is desired to lower the boat, the pressure on the brake K of the hauling
drum L on the shaft carrying the two grooved pullies H is relieved, so as to permit
of the rotation of the shaft and pullies, whereupon the weight of the davits together
with the boat will cause them to descend, the lower end or heel of the davits
together with their blocks, sliding down the guides C, until the block is arrested
by the stop C¹ Figure 4. During this motion, the curved inner face of the davits
in passing over the pullies H will be pushed outward thereby, so that the davits
will eventually occupy the position A' Figure 1.
'
On now continuing to release the ropes from the pullies, the davits will commence
to turn outwards on their pivotted connection with the slides B, occupying
successively the positions indicated at A³ and A" or A', according to the height of
the water level.
During this motion, the lorries F together with the boat will by degrees roll
along the curved surface of the cradle as the upper end of this gradually assumes
the more or less horizontal position, so that when the davits have assumed the
partially or wholly immersed position at A' or A', the boat will be free to float off
the lorries. The davits are then lowered still farther, say to the position A® so as
to be quite clear of the boat, unil this has moved away, when the davits are drawn
upward again.
If passengers are to be lowered in the boat, they can be conveniently embarked
when the davits and boat are in the position A', the boat being then sufficiently
high above deck to prevent any indiscriminate rush.
Thus it will be seen that the lowering of the boat can be effected with ease and
rapidity by the sole action of gravity, that it is deposited at a safe distance from
the side of the ship, and that there are no hocks or tackle on the davits from which
it has to be released.
The davits and cradles being open or trellis-like structures of flat bars, they
offer but little resistance in passing through the water, and consequently a boat
may be safely lowered into the sea before the way is off the ship, and being about
eight yards clear of the ships side, there is no danger of its drifting into the screw
race.
In calm weather the boat may be recovered by floating it over the lorries and
heaving up the davits by the driving rope or chain.
When raising up the davits from the lowest position at A, the heel thereof is
prevented from sliding up the guides in consequence of the very oblique direction
cf the pull on the rope, by causing the heel when in this position to, butt at a
Figure 4, against shoulders c formed by notching out the guide bars C. When
the davits have been raised to the position A Figure 1 where there is no farther
tendency of the heel to ride up, the heel will have been turned so as to be free of
the shoulders,
с

page_text: In rough weather, there might be danger of damaging the boat while bringing
her over the lorries on the immersed davits. In such cases the davits are kept in
the raised or partially raised position, and the cradles E are turned on their pivots
into the reversed position as shewn at A 7 Figure 2; the upper ends of the cradles
are then stayed by a "span" from the heads of the cradles on the opposite side of
the ship, or from a point on deck, and a tackle having been attached to such upper
end, the boat is raised as from ordinary davits, and is temporarily secured till the
weather moderates.
When this occurs, the davits are lowered somewhat and the cradles, with the
boat hung therefrom will be canted inboard on their pivots as at A³ Figure 2 thus
bringing the lorries under the boat, which is then lowered on to them, the cradles
being then secured in the position as at A' again.
The inner ends of the steel ropes I are secured to the pullies H and they are
made of such a length that when the davits are lowered to their lowest position A
Figure 1, a complete turn will still remain on the pullies.
One of the pullies H is keyed on its shaft, but in order to provide means for
adjusting the ropes so that the strain on both shall be equal, the second pulley is
fitted loose on the shaft and is secured thereto by a friction clutch, so that it can
be turned on the shaft for exactly adjusting the length of uncoiled rope for
effecting the above object.
The davits are suitably braced together as shewn at Figure 7, and the pullies H
are provided with outside flanges H to prevent lateral motion of the davits.
The above described construction of davits also has the advantage that when it
is employed for lowering boats of large dimensions such as heavy steam launches,
these may be carried by three such davits instead of only two, whereas with
ordinary davits, boats can only be suspended from two points near the extremities.
It will be obvious that, this construction of davits may also be employed for
lowering submarine Whitehead and other torpedoes.
Although I prefer to pivot the davits to vertically sliding blocks as described, as
this enables them to be brought into the requisite low position for floating off the
boat without making them of excessive length, yet it is obvious that they might
also be constructed to work on pivots fixed to the ship's side.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Apparatus for lowering and raising ships boats, consisting of arms or davits,
extending some distance down the ships side, where they are attached to pivots,
the upper ends of the davits being provided with curved cradles on which run
wheeled lorries that carry the boat, so that on lowering the davits on their pivots
by suitable rope or chain gear, they turn on their pivots from a vertical to a
horizontal or lower position, while at the same time the lorries with the boat roll
on the curved cradles in such manner as always to maintain the boat in its
horizontal position and thus enable it to float off the lorries when the davits are
lowered below water level, substantially as described.
2. In apparatus for lowering and raising boats such as is referred to in the first
claim, mounting the pivots of the davits on vertically sliding blocks, so that the
davits can first be lowered to a lower position before they are made to turn on their
pivots, substantially ae described.
3. In apparatus for lowering and raising boats such as is referred to in the first
and secoud claims, forming the inner face of the davits with an inward curvature
so that when in the raised position such inner face overhangs the deck to some
extent, and when lowered, the curved face, in passing over a pulley, will cause the
davit to turn outward somewhat on its pivot, substantially as described.
4. In apparatus for lowering and raising boats such as is referred to in the first
claim, arranging the curved cradle to turn on a pivot on the davit, so that by
inverting the position of the cradle on the davit, this can be used as an ordinary

page_text: davit for raising or lowering boats by tackle, substantially as described with
reference to Figure 2 of the drawings.
5. In apparatus for lowering and raising boats such as is referred to in the first
claim, constructing the curved cradle with laterally projecting top and bottom
flanges that form closed loops at the ends, between which flanges the wheels of the
lorry are arranged to run while being effectually secured to the cradle, substantially.
As described.
•
6. The improved construction of ships davits, combined and operating as herein
set forth.
ABEL & IMRAY,
Agents for the Applicant.