A NEW METHOD OF CONSTRUCTING SHIPS' DAVITS TO RENDER THEM MORE RAPID OF ACTION IN CASE OF COLLISION AT SEA
Year: 1884

page_text: I, PAUL PROSPER BONNEFOY of French Nationality a duly certified Ship Master
and Captain in the service of the " Messageries Maritimes Co do France" of
Marseilles, in the department of Des Bouches de Rhone, France do hereby declare
the nature of my Invention for A NEW METHOD OF CONSTRUCTING SHIPS' DAVITS
TO RENDER THEM MORE RAPID OF ACTION IN CASE OF COLLISION AT SEA and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The main object of this Invention is to alleviate to a certain extent, by means of
improved mechanical apparatus, the terrible consequences of collisions at sea, as it
is under these circumstances and when vessels can only rely upon their own
assistance, that the application of the proposed system proves useful.
The boats are placed inside the vessel as usual thereby avoiding anything
projecting outside. Being thus lashed ready for sea the largest can be launched in
three minutes by two men only.
The necessary operations are of the greatest simplicity requiring but little labour.
The results obtained are due to a unique arrangement by which weight is brought
into action to effect movement.
Upon the framework now employed either to support the boats, or in the
construction of covered in gangways or bridge houses on modern vessels, is rivetted
at a proper distance from the outside edge, a piece of forged ironwork A (sco
Sheet I, Figures 1 and 2), which constitutes the part of a hinge of which the other
part is formed by the lower end of the davit P. M. T. This is of a particular form
and will be gone into in detail; but it is to be understood, firstly, that on account
of the hinge at A, it can be moved in the direction of the dotted line T. T¹. Tu
and by this movement has its end T carried outside the vessel.
In the ordinary position when at rest, as represented by the left side of
Figure I, the davit embraces in its bend the boat which is thus placed when inside
the vessel.
The end T is provided with an ordinary binding shackle O, on which is hooked
the host's tackle

page_text: At M, in the middle of the davit another shackle of peculiar form is placed, on
which the tackle R is hooked, which serves either to steady the putting out of the
davit or to square it into place when the boat after having been hoisted is required
to be placed inside.
The shackle M is of unusual length, which serves to increase the lever arm, on
which the tackle R, acts when bringing back the davit (see the right side of
Figure I.), a kind of shoulder fixing it in the required position.
The end P. is shown in detail in Sheet I, Figure 3. Here the davit is divided
into two strong jaws m. m. between which is taken the double half of the
hinge C. which by means of a very strong bolt is hinged to the single half A.
The two jaws m. m². are exactly at right angles and serve as stop blocks to the
two extreme positions that the apparatus can reach.
The jaw m. is remarkable on account of the small flat surface S. limited in extent
by the shoulder E.
On S the keel of the boat is intended to rest. At the end of the jaw m¹. and on
its outside the piece L should take its bearing, it being a kind of pawl; hinged to
the framework at G and moving easily to the lino l. 1. being caused to do so by
the weight.
When the piece L is lifted up as shewn in the Figure and there held in position
by the siezing a, the jaw m' is firmly fixed between it and the piece A and the
davit becomes immovable.
When not in use let it be supposed that a perpendicular line is passed through
the central point of the hinge (Sheet I, Fig. I).
It will be seen firstly, that the end T is outside of this line and it is evident that
if the pawl L falls at a weight acting on the point I would set the apparatus in
motion and draw it towards the second position outside.
It will also be remarked that the surface S arranged above the jaw m comes just
on the perpendicular line in question and that a weight resting on it cannot have
any effect in putting the apparatus into motion, but tends rather to fix it.
The two frames, on which the davits are fixed, are connected together by two
angle iron stringers, the first uniting the frames just under the davits, which is seen
in Sheet 2, Figure 1, C. C. C; the second is more inside and parallel with the first,
which causes it to be hidden and it will be designated for reference by C¹. C¹.
The bolt B which forms the hinge of the davit (sce Sheet I, Figure 4) is
continued inside beyond this hinge. Its end works in a kind of framing B¹
substantially fixed to the stretcher C' C'. Between this framing and the binge, the
bolt serves as the axis of another pieco U which will be called a lover chock and of
which a particular description is given (Sheet I, Figure 5).
This piece has two branches U. U₁; which have both the same shape as the part
of the boat on which they rest.
The bolt passes at V and the pieco oscillates upon this axis.
It is easy to understand that when the lever λ is raised or lowerod, if the boat
be taken between the two arms U. U¹, it will be carried by them.
For example say that the davit is in position inside, immovably fixed by the
pawl, and supposo the boat hoisted and hanging on its tackle (of which the cleats
should be fixed in the boat itself) and that it is necessary to have all ready to lower
it into the sca :—
To do this, all that is required is to lead it on to the flat surface S of the jaw m,
at the same time catching it in the chock arins, then, by pressing on the lever a the
arm U acts on the boat, holding the keel against the shoulder E, and the side at B
against the davit, the end of the lever which is ring shaped being kept in this
position by a strong lashing to the ring bolt I.
The boat is thus strongly held in position and proof against all rolling or other
movement of the vessel, being jammed between the davit, the shoulder E, and the
arm U of the chocks.
Still when the vessel is rolling the boat has a tendency to rock on its keel and
in consequence, strain the arm of the chock.

page_text: To prevent this, all that is necessary is to fix on the edge of the boat, a strong
flat lashing S, which has a thimble at its end (Sheet I, Figure 1), this lashing being
well stiffened and siezed to the ring bolt I. the same as the ring of the lever, λ,
stops the rocking motion and also, it will be noticed, helps. the pawl L to fix the
davit inside.
Let us see now what would be the manoeuvre required to put the boats rapidly
in use, in a time of danger, this being the object of the apparatus. As it has
already been stated, two men are enough for the largest boats, one at each davit..
They commence with the ring bolt I, cutting at the same time the siezing of the
lashing and that of the lover å, taking hold of this, raising it on getting up, the
arm U₁, pushes the keel from the support S; the boat is then suspended on' its
tackle and bears on the end T of the davit, which it draws outside with it, as soon
as the lashing a, of the pawl L is cut and lots the said pawl fall. The weight
above alone by its action does all the rest, and the davit takes the position as
shown at the right side of Figure 1, it being led there by letting out the tackle R,
and it only remains to lower the boat into the water. It will be seen that it was
only necessary to have two men to obtain the desired object and these bad but
little force to exert; and in two or three minutes at the outside a vessel can have
all her boats ready for service and thus prevent by the promptitude of this action
the rapid and disastrous effects of a collision with a straight or hatchet stemmed.
vessel.
The fitting up that I have described can be simplified as far as mechanical
construction is concerned.
The chock lever can be replaced by means of sailor work (Sheet 2, Figures 1
and 2).
A strong flat lashing S fixed to the davit, completely encircles the boat, and is
then siezed to the ring bolt I. The operation is quite as rapid, only the men
require handspikes, with which to push the boats keel off its bearing S
The pawl L can be constructed as shewn in Figures 2 and 28 and is then a
suitable piece of hard wood, properly faced with iron. This moves horizontally
around the bolt B, rivetted to the frames, a brass pin going through a hole, holds
it in the position, where it stops the jaw m¹ and fixes the davit.
We have hitherto only spoken of boats mounted on frames, (by which is meant
a continuation of the ship's ribs) or which is the same thing mounted on houses on
deck, but the system can be applied equally as well, without either framework or
houses on deck, to any part of a vessel (sec Sheet 2, Figure 3), in which case the
piece A, which acts as a part of the hinge is continued and becomes a strong
upright, substantially fixed to the vessel's deck, out of the way of the sides, the
two uprights being connected together by the brace or stringer C¹. C'. (not seen in
the Drawing), upon which is rivetted the ring bolt I to which the lashings S and S¹
are siezed.
The movable part of the davit remains the same. The pawl L is applied to the
upright through whoso thickness it passes. The action will be understood by
reference to the Drawings, the part Ľu being much the heavier keeps it in the
position which fixes the davit.
Whatever system may be adopted, the boat having been rapidly put out, I will
now describe by what means the quickness of its being floated may be increased.
As a rule this operation is much impeded by the canvas cover, but can be
modified as follows. The cover is divided into two halves, lengthways, thus
making two half covers, which are roped. At the two ends of each half, a flap or
lug with a thimble to it, is attached, and along the roping at the sides, six or eight
smaller lugs with thimbles are attached (Sheet 2, Figure 4). To put in position, at
each end of the boat, an end of single ratline line is placed Q. Q', forming a clew
passing through the two end lugs of the covers and drawing them together, at the
same timo tightening tho bolt roping, which is still further connected lengthways,
by a lacing, the turns of which go over the jackstays at the davits heads, making
the cover, by being drawn up in the middle, to assume a rooflike form.
.

page_text: Let us now. see'in a moment of danger, when rapidity of action, is so precious,
-how this cover can be got rid of.
As soon as the boat is put outside, the two men jump into it and cut the ratline
line forming the clews and also the lacing, having only to throw overboard the
covers and then take hold of the tackle falls and lower the boat themselves. Here
an objection presents itself:-
1. Would two men, one at each tackle fall, be sufficient to lower a large and heavy
boat? This could be done by the use of a simple little apparatus, viz., a running
cleat (Sheet 2, Figure 5) of which the stem is rather longer and stronger than
usual, with a groove the same size as the tackle fall, making two screw turns round
it; this would constitute a brake amply sufficient for the object in view. So far
it has only been a question of putting out boats, but it is also proper to go into
the matter of how they are to be taken in again, particularly, should this be
.required to be done when the vessel is in motion and rolling, a rare case. however,
as there is no rolling while in port, and a vessel using her boats at sea, can always
choose the lee side on which to carry out the operation.
In the thimble of the lashing S' (see Sheet 2, Figure 6) the runner of the tackle
is hooked, of which the lower block is fixed against the edge of the deck, the
runner going through a cleat or chock fixed outside the frames. It will be easily
understood on looking at the figure, that on paying out gently the tackle the boat
being kept outside the vertical line will hold back the davit, which cannot be
thrown violently back or damage itself by striking against its base. This
arrangement will answer equally as well when the vessel is heeled over a good
Meal, and the weather side boats are required, the tackle carrying them outside.
Special tackles are not necessary for each boat, the first tackle to hand can be
used in the rare event.of its being needed.
As can be easily perceived all that is sought after for the boats, is to have them
sheltered inside the vessel.
Support for the keel on solid points, is obtained by this system, combined with
advantages of such rapidity of action, that its adoption might in future save many
valuable lives.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The improved davit for supporting ships' boats and enabling them to be
lowered into the water with great safety and rapidity, consisting of a lever PMT
pivotted at its lower end P, while the boat is secured by suitable tackle to its free
end, and suitable tackle R is fastened to the middle of the davit at M for the
purpose of steadying the boat in its descent or squaring it into position to be
supported on the surface S.formed on the davit directly over the centre of its
pivot, the davit being so shaped that when the boat hangs from its free end the
weight will tend to cause the lever to turn on its pivot and so lower the boat into
the water, whilst when it is desired to secure the boat on the vessel its keel is
supported on the surface S.whereby its weight is taken off the free end of the davit,
all substantially as herein described.
2. The combination with the ships' davit described in claim 1, (a) of means for
preventing the lever from turning on its pivot, and which consists of a lever L
pivoted so as to be capable of bearing against the jaw m' on the davit P M T and
provided at its free end with an eye by which it can be readily secured to and
detached from the davit by means of a lashing a; (b) of means for securely holding
the boat in its fixed position when the keel is supported on the surface S of the
davit, and consisting of a lever à pivotted on the same centre as the davit, and
having arms U; U adapted to bear against the sides of the boat and receive the
keel between them, the free end of such lever being formed with an eye to receive
a lashing for securing the lever to a ring bolt I, and by cutting which lashing the
lever can be at once turned on its pivot to release the boat when necessary, all
substantially as herein described,

page_text: 3. The combination with the davit for ships' boats and the means for securing
and lowering the same rapidly as described in claims 1 and 2, of a flat lashing S¹
fixed to the edge of the boat and having an eye at its free end to receive a lashing
for securing it to the ring bolt I so as to prevent the boat rocking on its keel when
supported on the surface S of the davit, during the rolling of the vessel, substantially
as herein described.
Dated 1 1
2 T