Floating Dock, designed especially for Localities where the, the Smallest Vessels have to be Docked.
Year: 1891

page_text: Date of Application, 10th Mar., 1891
Complete Specification Left, 9th Dec., 1891-Accepted, 9th Jan., 1892
PROVISIONAL SPECIFICATION.
Floating Dock, designed especially for Localities where, there being
Little or No Rise and Fall of the Tide, the Smallest Vessels have
to be Docked.
I TRAJANO AUGUSTO DE CARVALHO, of The Hollies, Chiswick Mall,
London, Naval Architect do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to reduce the quantity of water that has to be
pumped out for raising a ship, to about the weight of the ship, and to admit of
raising all parts of the dock above the water for cleaning and painting, and further
when docking a ship to render it unnecessary to sink much more than the horizontal
pontoon, upon which the ship is supported.
In similar docks it is usually necessary in docking to sink three or more pontoons
viz.: one forming the bottom and two or more the sides of the dock, but in this
dock the main side pontoons remain afloat at the same draught of water during the
whole operation of docking a ship; and it is in this respect that I greatly reduce
material and labour in the first cost of the dock as compared with the most simple
form of floating dock hitherto known.
The dock consists of a horizontal pontoon divided into numerous compartments
which may be separately emptied or filled with water. This pontoon is of sufficient
displacement to float with its upper surface just at the level of the water when it
is supporting the largest vessel which it is desired to lift. The upper surface
of the horizontal pontoon is surrounded by a coaming. In this coaming there
are valves which are closed as soon as the top of the dock is awash, and it
thus gives a freeboard to the horizontal pontoon equal to the height of the
coaming.
The horizontal pontoon is built with frames rising up vertically from projections
which stand out from its sides at distances apart from one another. Between these
frames are situated the side pontoons or floats.
The upper part of the vertical frames remains always above water a sufficient
height to accommodate boilers for supplying steam to work centrifugal or other
pumps. The pumps themselves arc situated within the horizontal pontoon so
that the water need not be lifted for discharge to an unnecessary height.
propose also to employ the side pontoons when so desired as depôts for coal and
other stores.
I
When the horizontal pontoon is wholly immersed it depends from the side
pontoons by means of wire ropes or iron standards gripped by powerful brakes in
the side pontoons and by means also of pawls so that the horizontal pontoon when
lowered has the assistance of the side pontoons giving large potential stability and
surplus displacement.
Or the horizontal pontoon may be secured to and lowered from the side pontoons
by other means. It is to be understood that the only weight thus depending and
controlled will be that necessary to cause the pontoon to sink steadily after water
has been admitted for sinking it.
Dated this 10th day of March 1891.

page_text: COMPLETE SPECIFICATION.
Floating Dock, designed especially for Localities where, there being
Little or No Rise and Fall of the Tide, the Smallest Vessels have
to be Docked.
I, TRAJANO AUGUSTO DE CARVALHO, of The Hollies, Chiswick Mall,
London, Naval Architect, 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:-
The object of this invention is to reduce the quantity of water that has to be
pumped out for raising a ship, to about the weight of the ship, and to admit of
raising all parts of the dock above the water for cleaning and painting, and further
when docking a ship to render it unnecessary to sink much more than the horizontal
pontoon, upon which the ship is supported.
In similar docks (such for example as are described in the Specification of a
prior Patent granted to Messrs. Clark & Stanfield dated the 9th day of February
1878 No. 553) it is usually necessary in docking to sink three or more pontoons
viz.: one forming the bottom and two or more the sides of the dock, but in this dock
the main side pontoons remain afloat at the same draught of water during the
whole operation of docking a ship, and it is in this respect that while I greatly
reduce material and labour in the first cost of the dock as compared with the most
simple form of floating dock hitherto known I provide a large reserve of stability
both transversely and longitudinally.
The dock consists of a horizontal pontoon divided into numerous compartments
which may be separately emptied or filled with water. This pontoon is of
sufficient displacement to float with its upper surface just at the level of the water
when it is supporting the largest vessel which it is desired to lift. The upper
surface of the horizontal pontoon is surrounded by a coaming. In this coaming
there are valves which are closed as soon as the top of the dock is awash, and
it thus gives a freeboard to the horizontal pontoon equal to the height of the
coaming.
The horizontal pontoon is built with frames rising up vertically from projections
which stand out from its sides at distances apart from one another. Between these
frames are situated the side pontoons or floats.
The upper parts of the vertical frames remain always above water, a sufficient
height to accommodate boilers for supplying steam to work centrifugal or other
pumps. The pumps themselves are situated within the horizontal pontoon so that
the water need not be lifted for discharge to an unnecessary height. I propose
also to employ the side pontoons when so desired as depôts for coal and other
stores.
When the horizontal pontoon is wholly immersed it depends from or is held
down by (as the case may be) the side pontoons by means of wire ropes or iron
standards permanently attached to it and gripped by powerful brakes in the side
pontoons and by means also of pawls so that the horizontal pontoon when lowered
has the assistance of the side pontoons giving large potential stability and potential
surplus displacement.
Or the horizontal pontoon may be secured to and controlled when rising or
falling from the side pontoons by other means. It is to be understood that the
only force thus controlled will be the small surplus weight of water necessary to cause
the pontoon to sink steadily after water has been admitted for sinking it or the
variations in buoyant forces in the horizontal pontoon in the operations of filling
and emptying.
It will be seen from the above that the side pontoons are never used as a lifting
power for docking a ship but are used for giving stability to the bottom pontoon
more especially at the time when neither bottom pontoon nor ship is capable of

page_text: giving stability and this I am enabled to do by providing for instantaneously
locking the side pontoons to the bottom pontoon by friction or like gripping
apparatus at any time during the raising or lowering of the bottom pontoon in
whatever position they may be in relatively the one to the other.
In the dock described in the prior Patent above mentioned the side pontoons were.
of a height equal to the height of the bottom pontoon and the side standards which
rose up from it.
In my dock as will be seen in the drawing annexed they are of considerably less
height and only descend into the water to about the same depth as the bottom
pontoon when it has been raised and has a vessel upon it which has been lifted out
of the water.
In the drawing
Figure is a cross section of the dock with the bottom pontoon lowered and a
ship brought into position above it.
Figure 2 is a cross section of the dock with the bottom pontoon raised and the
ship upon it lifted out of the water.
Figure 3 is a side elevation of the dock and
Figure 4 a plan.
For instantaneously connecting the bottom pontoon to the side pontoons the bottom
pontoon may have rods or parallel bars projecting up vertically from it in front of
the side pontoons and these may be gripped by friction clips carried on the side
pontoons such friction clips might be made in a similar manner to what were
known as compressors formerly used for arresting the recoil of guns.
During the time of raising a ship out of the water men may be stationed at each
of the clips or holders to instantaneously bring them into action or release them
whenever necessary or they might all be actuated simultaneously by hydraulic or
other power.
Where wire rope is used for forming the connection between the bottom and the
side pontoons the grip or brake may be that known as the Bullivant brake which
locally bends the rope slightly-the rope may be held at its ends between the
bottom pontoon and the top of standards which rise up from it whilst the brakes
may be on the side pontoons. In this case the precise amount of slackness in the
ropes may be given by screws at the heads of the ropes.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be perforined I declare that what I
claim is :-
1. A floating dock formed of side pontoons which remain afloat at or near the
same draught of water during the whole operation of docking a ship and a bottom
pontoon which can be lowered or raised by the admission of water or pumping
water out from it and which can when it is being raised or lowered be quickly
locked by locking mechanism to the side pontoons whatever may be its position
relatively to them.
2. The construction of floating docks substantially as herein before described.
n
1
1001
CARPMAEL & Co.,
Agents for the Applicant.