IMPROVEMENTS IN FLOATING DRY DOCKS OR PONTOONS
Year: 1884

page_text: 1, ALEXANDER TAYLOR of Queen Street in the City and County of Newcastle-
upon-Tyne Engineer and Managing Director of a Dock Company do hereby declare
the nature of said Invention for "IMPROVEMENTS IN FLOATING DRY DOCKS OR
PONTOONS to be as follows:-
"
The ordinary floating dry docks or pontoons are usually constructed with parallel
sides of uniform height, or they rely upon other structures for their stability, and
in sinking them sufficient water or tank space inust be provided to overcome the
buoyancy of these portions, which water has afterwards to be discharged by
pumping or otherwise before the dock or pontoon with the ship can be lifted, a
great and unnecessary dead weight being required to be raised.
According to my invention I propose to construct the sides in the form of a
girder or beam, having their greatest depth at the centro (for a certain distance fore
and aft parallel to the bottom forming a level platform) from which they taper
(preferably in a curve) to the ends, allowing only sufficient margin of area of side,
at the various drafts, to give ample stability under the most severe practical working
conditions, careful calculation being made of the special work to be done and of
the stability required for the dock or pontoon and its load at the various drafts
throughout the lift, regard being given to the case of the largest and most tender
ship it is intended to lift.
At each corner I propose to construct a tower which, with the raised centre
portions of sides, facilitates getting into and out of the interior portions of dock or
pontoon, assists the ventilation and is convenient for mooring the dock and the
ship (being provided with "bollards") and for general bandiness, and a light
platform nay be constructed from each tower to the raised centre portion of sides
gangway" alongside the ship.
as a "
I propose to make the bottom of the dock or pontoon of cellular construction,
the tanks being so arranged as to drain the water into a central portion (or
portions) so that the suction pipes from pumps may be simplified in arrangement.
The pumping machinery will generally be conveniently situated within the pontoon
or dry dock.

page_text: According to this mode of construction the weight of a dock or pontoon and
consequently the first cost will be greatly reduced, the tank capacity required to
sink it also considerably reduced and thus less pumping power required, while time
will be saved in sinking or raising it. The top weight will be also much less and
yet the stability and strength of the dock or pontoon will be secured and the form
of the sides allows the air and light free access to the ship in the dock or pontoon
which I consider will be found a great advantage.
Dated this 10th day of Tuno 1004

page_text: I ALEXANDER TAYLOR of Queen Street in the City and County of Newcastle
upon Tyne Engineer and Managing Director of a Dock Company do hereby declare
the nature of said Invention for "IMPROVEMENTS IN FLOATING DRY DOCKS OR
PONTOONS" and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The ordinary floating dry docks or pontoons are usually constructed with parallel
sides of uniform height or they rely upon other structures for their stability, and
in sinking them sufficient water or tank space must be provided to overcome the
buoyancy of these portions. This water has afterwards to be discharged by
pumping, or otherwise, before the dock or pontoon, with the ship, can be lifted,
besides a great unnecessary dead weight being required to be raised.
According to my invention I propose to construct the sides in the form of girders
or beams having their greatest depth at the centre (a certain distance fore and aft
parallel to the bottom may form a level platform) from which they fall preferably
in a curve, to the ends allowing only sufficient margin of capacity of side at the
various draughts, to give ample stability under the most severe practical working
conditions, careful calculation being made of the special work to be done and of
the stability required for the dock or pontoon and its load at the various draughts
throughout the lift, regard being given to the case of the largest and most tender
ship it is intended to lift.
At each corner I propose to construct a tower which, with the raised centre
portions of sides, facilitate getting into and out of the interior portions of dock or
pontoon, assist the ventilation' and are convenient for mooring the dock and the
ship and for general handiness; and a light platform may be constructed from each
tower to the raised centre portion of sides as a "gangway" alongside the ship.
propose to make the bottom of the dock or pontoon of cellular construction, the
tanks being so arranged as to drain the water into a central portion (or portions)
so that the suction pipes from pumps may be simplified in arrangement. The
pumping machinery will generally be conveniently situated within the pontoon or
dry dock.
According to this mode of construction the weight of a dock or pontoon, and
consequently the first cost, will be greatly reduced, the tank capacity required to
sink it also considerably reduced and thus less pumping power required, while time
will be saved in sinking or raising it. The top weight will be also much less and
yet the stability and strength of the dock or pontoon will be secured and the form
of the sides allows the air and light free access to the ship in the dock or pontoon
which I consider will be found a great advantage.
DESCRIPTION OF DRAWINGS.
On the accompanying sheet of drawings Figure 1 is a side elevation and Figure 2
a plan of a floating dry dock constructed according to my invention Figures 3, 4
and 5 are cross sections of same shewing the form of the structure at centre, at
ends and through the towers at corners. The outline of a steamer is shewn in the
dock resting upon the bloola

page_text: A A are the hollow girder shaped sides of the full depth of dock at the centre,
where for a certain distance they run parallel with the bottom, as from B to C
sweeping downward from these points till they join the end towers D D D D where
they are just a little deeper than the top of blocks E E E. The sills F F across
the ends of dock are just a little below the top of these blocks so that the ship will
readily float over them. G is a light platform gangway carried all round the ship
on suitable supports for facility of access protected by handrailing.
The engines, boilers and pumping machinery are arranged within the dock at one
end. No detail is shewn of the construction of the sides and bottom or tanks, as
to bulkheads frames, floors or stringers, as these will be arranged to suit the special
requirements of each dock and do not form part of my invention except in so far
as their arrangement is affected by the peculiar form of the sides of dock.
The dock is fitted with all the usual cocks, valves, sluices, suction pipes and other
interior fittings and with means for access both external and internal not shewn on
drawings.
It will be seen by reference to Figure 1-in which the dock with the Steamer
in it is afloat that perfectly free access for light and air all round is afforded,
especially from near the centre of length toward each end, by the tapering form of
the dock sides which also affords great facility for conducting repairing work
cleaning or painting the bottoms of docked vessels.
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
Floating dry docks or pontoons constructed with the sides tapering longitudinally
for the purpose of reducing the area of side in proportion to the stability required,
reducing the weight of the dock and the capacity of tanks and allowing light and
air free access to the vessel in dock substantially as shewn and described.
Dated the 13th day of March 1885.
ALEXANDER TAYLOR.
W. Lloyd Wise,
Per C. E. Brougham,
46, Lincoln's Inn Fields, London, W.C.,
Applicant's Agent.