Improvements in Floating Dooks.
Year: 1895

page_text: Date of Application, 11th Nov., 1895
Complete Specification Left, 11th Aug., 1896-Accepted, 26th Sept., 1896
Improvements in Floating Dooks.
LYONEL EDWIN CLARK 11 Victoria Street Westminster Engineer do hereby
declare the nature of this invention to be as follows:-
My invention is for an improved method of rendering floating docks self
docking.
My invention consists firstly in building the body or lifting portion proper of a
floating dock in the form of three or more separate caissons running transversely
across the dock from wall to wall, such caissons lying between the said walls and
being attached only to them by movable attachments, so that any and every caisson
can be removed at will from the dock and lifted thereon or elsewhere for the*
purpose of inspecting its underwater portions and secondly of the said arrangement
of caissons in connection with a watertight joint between them for use in cases
where an ordinary floating dock is fitted with bulwarks, gates or caissons at its.
ends, so that its lifting power is increased by pumping out water from the pound
formed by the said gates, bulwarks or caissons and the walls of the dock.
Dated this Twenty-first day. of November 1895.
1, LYONEL EDWIN CLARK, of 11 Victoria Street, Westminster, 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 consists in an improved form of floating dock, whereby the said
dock is rendered self-docking, that is to say, that any or every portion of the same
can be got at for the purposes of inspection or repair, without the aid of divers or
any separate structure or structures, and also of a means whereby the same end can'
be obtained when an ordinary floating dock is used more or less as a graving dock,
that is to say, when bulwarks, gates or caissons have been fitted to the ends of the
said duck, for forming with its vertical sides or walls "a pound" from which water
can be pumped out.
I attain this end by making the floating dock of two side walls and of three or
more pontoons or caissons which run transversely across the dock from one side
wall to the other. Each of these caissons is a distinct and separate structure
complete in itself and each is separately connected to the side walls by means of a
bolted or other form of easily removable joint. The width of every caisson is'
consequently always less than the distance between the two walls, and it does not-
pass under or beyond the said walls in any way. This allows the walls to be built'
in the form of a continuous structure over their whole height and does not lessen*
07
- "

page_text: their longitudinal strength as girders, as is the case in some forms of docks where
the body is also constructed in the form of separate caissons, but which caissons
pass under the walls, to the bottom of which they are attached. In this case the
walls practically sit on the top of the pontoons and in consequence have their
height as continuous girders reduced by the height of the pontoons and their
longitudinal strength proportionally weakened.
When the floating dock is to be used more or less as a graving dock, that is to
Bay, when a "pound" is to be formed from which water can be pumped out so that
by the pumping out of water from this pound the lifting power of the dock may
be increased I form the caissons with their sides raised to the height or thereabouts
of the gates, caissons or bulwarks which are to close in the ends of the pound and I
also close up the spaces between the separate caissons. To effect this I prolong
the end of the side plating of the upwardly extended sides and also the ends of the
deck plating of those pontoons which are in juxtaposition to each other. This
extension of the plating forms therefore a sort of projecting flange at the end of
the caissons. These projecting flanges are then joined together by any form of
removable watertight joint, a preferable form being that of an iron strip having
on its underside an iudia rubber or other packing. This strip is bolted to the
respective flanges that come opposite each other, and the packing being compressed
by the bolts makes the said joint watertight. Any other form of joint however
may be used providing that it renders the joiuts between contiguous caissons
watertight, and converts the decks and sides of these into oue continuous watertight
trough.
It will be evident from the above that the gates, bulwarks or other structures
with which the ends of the dock are fitted are attached to or made tight against
each end caisson of the series; and not to the walls themselves and the pound is
formed by the caissons and their extensions and is independent of the walls.
The said caissons or gates take into slots or against cills rivetted to the deck of
the pontoons and extending up the raised sides of these, the edges or bottoms of
the gates or caissons making themselves tight against the said slot or cills. There
is no special position for these slots or cills which may be placed anywhere across
the deck of the pontoons, and indeed it is preferable in some cases to have more
than one series of slots or cills so that the position of the caissons or gates may be
adjusted to suit the length of the ship on the dock thereby concentrating the lifting
power of the dock and its pound directly under or nearly under the vessel to be
lifted, and thus avoiding all strains either to dock or vessel from the overhanging
portion that is to say that portion of the dock on which the ship does not bear.
The following is the method preferably followed when it is required to self dock
one of these improved docks. In the first case all or nearly all the water is pumped
out of the interior of the compartments of the dock. Workmen then descend
between the sides of the caissons and the walls, having first in the case of the
graving dock removed the special joint on the decks and sides of the caissons
herein before described. They then disconnect preferably alternate caissons, but
any one caisson may if desired be specially removed or any number of caissons
providing however that sufficient be left so as to keep the walls together in their
proper position. When the caisson or caissons are unbolted they being separate
complete structures float free of the dock and can be treated in any of the following
ways. They may be completely towed away from the dock and repaired elsewhere
or they may be docked in the ordinary manner on the remaining caisson or caissons
or what is a preferable manner, the dock with its remaining caisson. or caissons can
be lowered under water to such an extent that the decks of the fixed caissons, that
is, those attached to the walls, come some three feet, below the level of the bottom
of the caissons that are floating free. These latter are then reattached to the walls
at this level and the dock being pumped out rises again and brings up with it the
detached caissons which now being made fast to the walls at the higher level have
their bottoms, when the dock has been lifted as much as necessary, well above the
water line and can be easily got at in all their parts.

page_text: A convenient form of dock is one where the body of the dock is made up of five
separate but similar caissons and a convenient way of docking these is to deal firet
with the two outside and the middle caissons in the manner described. After
examination or repair these are replaced in their original positions by a process
which is the inverse of that adopted for raising them and then the two intermediate
caissons are dealt with in their turn. By this means of procedure the dock-will
In this manner.
always be in a condition of equilibrium in a fore and aft sense.
the whole of the caissons of the dock can be examined in two operations. The
remaining portion of the dock consisting of the walls is likewise lifted in two
operations, these consisting in alternately heeling the dock first one side and then
the other, by which means the bottoms of the said walls are alternately brought.
out of the water.
A suitable form of dock is one where the bottom of the wall in its normal
position does not extend below water to the same extent as that of the caissons as
in this case the angle of heel required to get the bottom of any wall out of water is.
very small.
The accompanying drawings Figures 1, 2 and 3 of Sheet No. I show a simple
arrangement of an ordinary floating dock on my improved principle. The body of
the dock consists of five separate caissons P. P. P. placed transversely across the
dock and between the two walls W. W. They are attached to these wails by means.
of cover plates C. C. bolting on to projecting lugs A. A. and A' A' rivetted to the
sides of the pontoons and to the walls respectively. Figure 4 shows a larger detail
of a suitable form of such attachment, where the lugs A and A' are in the form of
a strong Tiron, and the cover plates C. C. are double, one on each side. The
actual connection is made by means of turned pins and cotters B. B. but bolts or
any other form of connection might also be used.
Sheet No. II, Figures 5 and 7 show a suitable method of docking the caissons of
the dock. In Figure 5 caissons Nos. 2 and 4 have been disconnected from the
lugs A' by the removal of the pins and cover plates and the dock has been lowered
under water until the lugs AA on the caissons have come level with the upper
lugs A" A on the wall, see Figure 7. The caissons are then made fast in this
upper position and the dock being pumped out brings the caissons out of water as
shown in Figure 5. Figure 6 shows how the alternate caissons 1, 3, 5 are lifted in
the same manner. Figure 8 shows the method adopted for getting the underwater
portion of one of the walls out of water, the dock being careeued to the opposite
angle when the other wall is to be got at in its.turn.
Sheet III shows the arrangement adopted when a floating dock has been fitted
with gates or bulkheads. Figure 9 shows a side elevation of such a dock (one
wall having been removed for convenience of illustration) fitted at one end with a
movable gate G, and at the other with a fixed bulkhead B. Figure 10 shows au
end elevation of the same and Figure 11 a cross section, showing two forms in
which the side plating S S of the caissons is extended upwards to about the height
of the gate or bulkhead used to close the ends. The same figures show the iron
strip a with its india rubber lining b, that makes the joint between the decks and
sides of the caissons.
Figure 12 shows an enlarged detail of the same joint; d,d, being the prolongation
of the decks or sides of the caissons. b the india rubber strip and a the iron
strip, c, e, being the bolts that hold the parts together and compress the india
rubber, the said bolts passing preferably through oval holes in the deck or side, so
that any expansion or contraction of the caissons may take place freely without
straining the joint. The method adopted for self docking these caissons and the
walls of the dock is the same as that described in the case of the ordinary dock,
with the exception that the strips a and b have to be removed by men descending
between the sides of the caissons and walls and penetrating into the spaces between
the pontoons as previously described; or if preferred studs or set screws may be
used for the above joint thus obviating the necessity of men penetrating underneath
the deck plating before the caissons are disconnected in the way described.

page_text: 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. A floating dock composed of two side walls and of three or more distinct.
pontoons or caissons, lying between the walls and attached to them by means of
removable joints, so that any one or more of them can be detached at any time,.
for purposes of self-docking substantially as described.
2. A floating dock of the above kind in which the sides of the pontoons or
oaissons are raised above their decks and watertight joints are formed between
them whilst at the two ends of the sories of pontoons, or elsewhere if required,
gates, caissons or bulwarks are fitted substantially as described.
Dated this Sixteenth day of May 1896.
LYONEL EDWIN CLARK.