US3442243A

US3442243A - Apparatus for ship stabilization

Info

Publication number: US3442243A
Application number: US697763A
Authority: US
Inventors: Philip Henry Tanner
Original assignee: Vosper Ltd
Current assignee: Vosper Ltd
Priority date: 1967-01-20
Filing date: 1968-01-15
Publication date: 1969-05-06
Anticipated expiration: 1986-05-06
Also published as: GB1164665A

Description

' y 1969 P. H. TANNER 3,442,243

APPARATUS FOR SHIP STABILIZATION Filed Jan. 15, 1968 Sheet of 4 May 6, 1969 Filed Jan. 15, 1968 P. H. TANNER APPARATUS FOR SHIP STABILIZATION Sheet 2 of4 Sheet MAM/ER.

May 6, 1969 Filed Jan. 15, 1968 May 6, 1969 HTANNER 3,442,243

APPARATUS FOR SHIP STABILIZATION Filed Jan. 15, 1968 Sheet 4 of 4 A United States Patent Int. Cl: B63b 39/04 US. Cl. 114124 1 Claim ABSTRACT OF THE DISCLOSURE A member rotatable about the longitudinal axis of a ship or other floating body is driven in alternate directions as required for the purpose of reducing roll. This member may comprise a chain. A regenerative drive means is connected to the chain means and is selectively workable as a pump for transferring hydraulic liquid from a sump means to a reservoir and as a motor driven by the hydraulic liquid to the sump means.

This invention relates to improved apparatus for ship stabilization.

The present invention is directed to apparatus for stabilizing the roll of a ships hull comprising guide means arranged in an athward ships direction around the ships hull, chain means extending around the guide means, reservoir means for containing hydraulic fluid under pressure, hydraulic liquid sump means, regenerative drive means operably connected to the chain means and selectively workable as a pump for transferring hydraulic liquid from the sump means to the reservoir means and as a motor driven by the hydraulic liquid passing from the reservoir means to the sump means, and roll sensing means responsive to rolling motion of the ship and operably controlling the functioning of the drive means as a motor and as a pump for damping motion of the ship by the reaction of drive imparted to the chain means.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings.

FIGURE 1 diagrammatically illustrates apparatus for stabilizing the roll of a ship;

'FIGURE 2 is a diagrammatic cross-section of a ship showing a roller chain type of stabilizing installation;

FIGURE 3 is a diagrammatic cross-section of a similar installation in which the roller chain extends over deck superstructure;

FIGURE 4 is an elevation of a suitable type of roller chain;

FIGURE 5 is an end view of the roller chain.

Referring now to FIGURE 1 of the drawings, the apparatus for ship stabilization consists of a wheel '10 mounted on an axis parallel to the centerline of a ship and driven by a variable output pump/ motor 11 in series with a sump 12 and a hydraulic accumulator 13. Associated with the pump/motor '11 is roll sensing apparatus 14, which may be entirely conventional, which determines the sign and magnitude of the pump/motor torque such that it is proportional to the angle of heel of the ship, or one or more of its derivatives and acts to counteract the roll.

To allow for losses either frictional or in the hydraulic system, practical apparatus would include a make-up pump, though this is not illustrated in the drawings.

When the apparatus is in use and the ship begins to roll to, say, starboard, hydraulic fluid passes from the 3,442,243 Patented May 6, 1969 accumulator 13 through the pump/motor 11 to the sump 12. The torque developed by the pump/motor 11, which is of course motoring, is proportional to the angle of roll and accelerates the wheel '10 in such a direction that the reaction tends to roll the ship to port. As the ship rolls back, the motor torque 11 decreases and when the ship rolls to port, the motor/pump 11 is driven by the wheel as a pump, with the torque again being proportional to the angle of heel. In this way the roll of the ship is damped out to a very considerable extent, and the fluid drawn from the accumulator 13 in one quarter roll is pumped back from the sump 12 in the ensuing quarter roll thus making the hydraulic system regenerative. The component 10 has been referred to herein as a wheel but it need not be a rigid element and may, for example, be made of heavy roller chain 10a as shown in FIGURES 2-5.

Thus the chain 10a may be extended around the hull 14 of the ship, as shown in FIGURE 2, over rolls 15 and driven by a driving wheel 16, located over the keel 17, which in turn is driven by a belt or chain drive '18 from the hydraulic pump/motor drive 1.

Alternatively, as shown in FIGURE 3, the drive may be extended over deck superstructure by additional rollers 15a by way of a wheel house 19. The increase in hydraulic radius of the chain in the above-deck installation results in the use of a lighter chain and lower powers.

Standard chains may be used: here a coice has had to be made on the pitch and number of rows. For instance, the three 2.5 in. triplex chains on the underdeck installation for a IOO-ton fishing vessel could be replaced by a single 2 in. decaplex, which would give the same weight per foot run. The three triplex chains were chosen for ease of installation.

One suggestion for a possible non-standard chain is shown in FIGURES 4 and 5: if a large number of installations were considered, it might very well be better economics to use such a design, which employs only one non-standard part. This will affect the design of the stabilizer since both the installations shown have been sized for minimum cost, which can be shown to occur when the price of the chain and its associated bits is equal to the price of the drive. If the chain becomes cheaper, then the minimum first cost installations will have a heavier chain and less powerful drive.

I claim:

'1. An apparatus for stabilizing the roll of a ships l1ull, comprising guide means arranged in an athwart ship direction around the ships hull, chain means extending around said guide means, reservoir means for containing hydraulic liquid under pressure, hydraulic liquid sump means, regenerative drive means operably connected to said chain means and selectively workable as a pump for transferring hydraulic liquid from said sump means to said reservoir means and as a motor driven by hydraulic liquid passing from said reservoir means to said sump means, and roll sensing means responsive to rolling motion of the ship and operably controlling the functioning of said drive means as a motor and as a pump for damping rolling motion of the ship by the reaction of drive imparted to said chain means.

References Cited UNITED STATES PATENTS 2,857,1-2-2 10/1958 Maguire 244-93 3,252,426 5/1966 Parr 103-162 TRYGVE M. BLlX, Primary Examiner.