Year: 1888

page_text: Date of Application, 28th Jan., 1888
Specification Accepted, 2nd Mar., 1888
We, GEORGE PAUL THOMSON of the firm of James and George Thomson, Engineers
and Shipbuilders, and JOHN HARVARD BILES, Naval Architect, both of Clydebank
Shipyard, Dumbartonshire 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 :-
Our Invention has for its object to obtain greater efficiency than has hitherto
resulted from the use of water chambers as a means of reducing the rolling of ships at
sea and to that end the present improvements consist (1) in making such a chamber
narrower at the middle line than at or near the sides of the ship one or both of the
transverse sides of the chamber being preferably of concave form in plan, and (2) in
providing means such as a movable partition plate or plates for varying the extent of
contraction of the chamber at or near the middle line.
The improved rolling chamber constituting the invention is illustrated in the accom-
panying drawings in which figure 1 is a cross section of part of a ship and figure 2 is
a plan of part of one of the decks between which and the deck below the chamber is in
the present instance placed. The rolling chamber A which is constructed of iron or
steel plates extends from side to sides its ends being close to the shell of the ship. One
side is in the example shown made straight and lies in proximity to a transverse
bulkhead B, but the opposite side is of concave form the curve extending from a point
near each end to the middle line of the ship where the chamber is greatly contracted.
This formation whilst serving the purpose above mentioned of contracting the chamber
at the middle permits of access to the cargo hatch C in the deck D. A plate or
partition E is or may be fitted to either or both sides within the chamber and is
adapted to be moved by screws F or other means to further contract to a greater
or less extent the passage in the middle of the chamber and regulate in part the
period of flow from side to side of the water with which the chamber is more or less
filled.
The effect of the above described formation of the chamber is to increase the period
of flow of the water from side to side for a given depth of water and length of chamber
so that for a given period of roll of the ship the depth of water may be increased.
This feature is especially valuable in a ship having a list, for, when the water in the

page_text: chamber is of little depth it tends to accumulate at the lee side and does not pass to any
extent across the middle line, whilst if considerable depth of water be employed it
flows freely from side to side of the ship and the extinctive effect is increased. The
shock of the water upon the ends of the tank is also less severe than is the case when
a chamber of rectangular form in plan is used.
Having now particularly described and ascertained the nature of our said Inven-
tion, and in what manner the same is to be performed we declare that what we
claim is :-
1. A rolling chamber for ships contracted at or near the middle line substantially
as set forth.
2. In a rolling chamber for ships the provision of a movable partition or partitions
for contracting the chamber more or less at or near the middle line substantially as set
forth.