Tub′u-lar Float′ing-dock.
One whose flotative power depends upon
[
2648]
air-tight chambers or cylinders.
These are wooden cases or iron caissons.
See also floating-dock.
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Machine for weaving a covering for cords. |
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Tubular floating-dock. |
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Tubular laryngeal forceps. |
Clark and Standfield's tubular dock (Fig.
6753) is composed of a number of circular wrought-iron tubes with hemispherical ends, stiffened inside by angle-irons at intervals of two or three feet, and securely braced together by T and angle irons above and below, forming transverse girders of sufficient strength to support the weight of a vessel.
These tubes are usually eight in number, and form a platform having sufficient buoyancy to float the superstructure and a ship.
The two outer tubes are of larger diameter than the interior ones, and the central tubes are longer than those at the sides, so that the structure is somewhat pointed at the ends.
The sides of the dock are each formed of from 12 to 24 similar vertical tubes, braced together and connected by a lattice-work platform at the top, running the whole length of the dock and forming a spacious gangway for the workmen.
The longitudinal tubes are so connected with the platform as to convert the whole dock into a beam or girder of great depth and rigidity.
The tubes are divided within into water-tight compartments connected by pipes.
The base of the dock contains about sixty and the sides about forty of these compartments, those of the sides being hermetically closed, so that the dock cannot sink.
A certain number of the bottom compartments are also hermetically closed, and the remainder are provided with valves at bottom, which can be opened and closed at pleasure, and with wrought-iron pipes which are grouped together, and all carried to a valve-house on the upper platform, where they are under the control of the valve-engineer.
When it is desired to sink the dock, the bottom valves are opened and the air allowed to escape at the valve-house until the dock settles down to the required level.
When it is desired to raise it, compressed air is forced into the tubes, expelling the water through the bottom valves, which are closed when the dock and the vessel upon it are raised to the proper hight.
The engines are in two pairs, placed within the vertical tubes near the center of the dock.
The whole of the water-tight compartments in the bottom are divided into four equal groups corresponding to the four corners of the dock, and by means of four corresponding valves in the valve-house air is forced into or withdrawn from either or all of these four groups, so that the dock may be kept perfectly level in raising or lowering.
