IL26362A - Ship stabilizer - Google Patents

Description

g «j 9/25/350 Patents Form No. 3 PATENTS AND DESIGNS ORDINANCE.

SPECIFICATION.

"SHIP SfABXLIZSR" I / WE , ...^^..^y...¾^iroi^BS....y 80GIAfB¾# IMC*--a--eorpoyation or anised and es at ag^¾ma ^---the---l«ws-"ef---t *--5-ta-te--- i---Ke uni tet State©...of.-^ei!loa*...ef...^ -^*te»y---PlAeB#...H€«r. ¥©2?¾, New --Xoplci tiaited States of America, 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 present invention provides a ship stabilizer and more particularly a stabilizer made mostly of existing ship structure such as the deck and supporting girder plates conventionally found in bulk cargo ships and the like.

The use of water tanks for the purpose of roll stabilizing a vessel dates back to the early 1900*s and Prahm's early contribution to the art. However, the industry did not consider the use of water tanks commercially feasible until the recent development of the flume type stabilizer; see, for example, Patent No. /<-.

Now that roll stabilization systems are being widely used, there is a present need in the art to reduce the expense, weight and volume requirements thereof so that the stabilizers detract as little as possible from the cargo handling capabilities of the vessel without losing their stabilizing effectiveness.

One concept of reducing the space and weight needed for stabilizers is to use existing ship structure as the container and damping means for the liquid stabilizing medium. But to use existing ship members as part of the stabilization system creates stress problems which must be solved so that the strength and structural function of these members are not undermined. One such solution is disclosed in L> JM Patent No. ^ , "^ , wherein the stabiliza- ion system for a liquid cargo tanker comprises the existing longitudinal and transverse structural bulkhead system which cooperates with a portion of the hull.

But the problem of using existing ship structure for the stabilization system in a bulk cargo vessel still exists, ^therefore, it is a primary object of the present invention to provide a stabilization system for a bulk cargo vessel wherein said system comprises, at least in part, existing structural members normally found in vessels of this type.

It is another object of the present invention to use existing structural elements of a bulk cargo vessel as part of the stabilization system therefor, without undermining or detracting from the structural functions of these elements.

It is yet a further object of the present Invention to provide a ship stabilizer which in part comprises the supporting deck girders normally found in bulk cargo vessels.

It is still a further object of the present invention to provide a plurality of stabilizing containers spaced throughout the length of the vessel.

Other and further objects of the present invention will become apparent with the following detailed description when taken in view of the appended drawings in which: Fig. 1 is a side elevation of a vessel schematically illustrating the positions of the stabilizer tanks in relation to the holes, corrugated transverse bulkheads, and deck; Fig. 2 is a side sectional view taken along line 2-2 of Fig. 1; Fig. 3 is a side sectional view taken along line 3-3 of Fig. lj Fig. I. is a developed fragmentary view of the restricting plate taken along line -U- of Fig. 2; Fig. s a sectional elevation view taken along line 5-5 of Fig. 3; and Fig. 6 is a sectional elevation view of the wing tank taken along line 6-6 of Fig. 5· Referring to the drawings in detail, there is illustrated in Fig. 1 a conventional bulk carrying cargo ship, generally indicated as 10, having a plurality of longitudinally spaced holds 12 separated by corrugated transverse bulkheads I and provided with a main or upper deck 16. A suitable number of longitudinal bulkheads 18 extend substantially throughout the length of the ship and divide holds 12 into a number of lateral compartments. Each hold 12 has one or more hatchways 20 through which bulk cargo material is loaded and unloaded. Sloping, elongated girder plates 22 are positioned across the hull, and each has one edge in supporting engagement with the underside of main deck 16 and its other edge rigidly mounted to the top of corrugated transverse bulkheads 1 · Any suitable manner, such as welding and the like, can be used to secure these edges to deck 16 and the supporting structure. For increased structural support, the girder plates 22 and their associated deck portion form in cross section a rigid triangular structure, better seen in Fig. 5.

An elongated narrow plate 22j. is mounted atop each corrugated bulkhead llj. and serves as a base or bottom to which the lower sides of plates 22 are secured.

In accordance with the present invention, a pair of wing tanks 30 shown looated at A and B in Fig. 1 are built in next to the hull just below deck 16 and serve as part of the stabilization system in cooperation with selected pairs of the girder plates 22. These girder plates form the sides of the crossover channel between wing tanks 30 as further described below.

Referring to Pigs. 3-6, each wing tank 30 has two liquid-tight bulkheads 3 and a sloping bottom plate 3- which has a vertical leg 36 and a horizontal leg 38 welded to deck 16 and the hull, respectively. A vertically mounted transverse web Ι is mounted in each wing tank with its edges entirely in contact with plate 3ij.» a portion of the hull, and a portion of the main deck 16. Web I4.0 serves to add additional transverse rigidity to the ship.

As can be seen in Pigs. 3-5» the portion of plate 3I . mounted across the area at which the space between girder plates 22 communicates with the respective wing tank 30 serves as a sloping restriction plate 1+2. A plurality of restrictions or cuts i| is provided therein and these openings decrease in dimension and cross section as they approach the bottom of plate \ Z so as to interfere as little as possible with the force distribution within plate i2.

Plate 1+2 terminates in an upper vertical leg I .6, the top of which is welded or otherwise secured to the underside of main deck 16, and openings I.8 are provided therein to reduce weight and to enable a free passage of air in a manner described below. A swash bulkhead 50 is provided in each wing tank, preferably near the center thereof in order to prevent local sway and to eliminate unwanted turbulence from the wing tank. The swash bulkhead contains a plurality of openings 52 across its face.

The operation of the present invention will now be described. It is readily understood that the sloping deck girders 22 function in their normal manner to give the required structural support to main deck 16, and that the space between girders 22 provides a connecting channel 51 between the pair of transversely aligned wing tanks 30 located at opposite sides of the hull. Additional structural support and rigidity is afforded by transverse webs 1+0 and liquid-tight bulkheads 32. In addition, girders 22 and bulkheads 32, along with bottom plates 3kt main deck 16 and the hull of vessel 10, define an elongated, enclosed liquid container or tank which, when filled with a body of liquid, serves as the passive stabilization system for vessel 10. As the ship 10 experiences roll in response to the action of the particular sea, the liquid within the stabilizer transfers from one side to the other in response to the roll, and the effective mass of the liquid shifts to impart a stabilization moment to the vessel. Restriction plates 1+ provide the, appropriate energy dissipation and liquid damping as the liquid transfers therethrough.

The air above the liquid surface transfers freely between the wing tanks 30 and the connecting channel through openings 1+6 or any uncovered cuts I+I4. in restricting plate 1+2. This transfer of liquid from one side of the stabilizer to the other continues as long as the vessel continues to roll.

Any suitable liquid such as fuel, bunker oil, sea water and the like can be used as the stabilizing medium within the stabilizer. The natural frequency of liquid oscillation within the stabilizer can be selected to match the particular conditions of the ship and sea by merely adjusting the height of the liquid within the stabilizer. To develop the proper moment magnitude, a predetermined plurality of stabilizers are built in into the vessel and can be partially filled with liquid to operate in the manner described.

Other and further modifications can be made to the present invention without departing from the scope thereof, and it should be understood that although only two stabilizer locations A and B were shown, any number of stabilizers can be used in order to obtain the desired magnitude of stabilizing moment required for a particular vessel. It should further be understood that although the plan profile of the container is shown as being C-shaped (see Fig. 3), plan container profiles of Z-shape and H-shape are also within the scope of the present invention.

Claims (1)

1. 26562/2 Claims 1· A bulk carrier vessel having a main deck and a hull and a passive stabilizer tank extending across said hull, comprising at least one pair of wing tanks each located beneath said main deck at an upper outboard side of the hull and having its inboard bottom wall formed by a downward end outward sloping plate having its top secured to the main deck under surface and its outboard edge secured to the respeotive hull side, said tank further including an interconnecting channel formed by a bottom plate extending the length of the tank, a pair of girder plates projecting upward and fore and aft respectively from said bottom plate and having their top edges secured to the under surface of said main deck so as to transmit supporting forces thereto, said girder plates extending athwartship and Intersecting the Inboard walls of the wing tank so that the interconnecting channel has a truncated profile in cross section, the fore and at dimension of the interconnecting channel being less than the fore and aft dimensions of said wing tanks so as to form a C-shaped tank, each said plate forming inboard side of each wing tank de ining a plurality of openings aligned with the profile of the interconnecting channel to permit substantial liquid passage into and out of the wing tanks during the roll cycle and to provide a suitable amount of damping thereto, said openings extending in zones from generally the bottom to the top of the tank for hydrodynamically damp-≠lng the liquid passage hut permitting a free transfer of air therethroug , and a swash bulkhead arranged transversely in each wing tank and provided with a plurality of openings so as to decrease the fore and aft swash movement of liquid therein during operation, and a body of liquid partially filling the tank so as to form an air space over all parts thereof in the interconnecting channel and the wing tank, the liquid level being such that the tank liquid oscillation is generally turned to the ship's roll, said vessel further comprising a corrugated transverse hulk-head secured therein contributing to the primary support for the main deck and having its top supporting said bottom plate of said tank so as to counteract the loading forces through the girder plates. 2· A vessel as set forth in claim 1 wherein the plates forming the inhoard sides of each wing tank oomprise an inhoard vertical section connected to the main deck and an outboard horizontal section connected to the hull* 3· A vessel as set orth in either claim 1 or claim 2 wherein the height of said wing tanks is substantially the same as the height of said connec ing channel. 26368/2 It* ; A vessel aae* set Jorth in any one of the preceding claims wherein a restricting plate having a plurality of openings therein is mounted across each end of said connecting channel where said channel communicates with the respective wing tank* 5· A vessel as set forth i claim k wherein each wing tank has a lateral dimension greater than the lateral dimension of said connecting channel· 6 A vessel as set forth in claim 5 wherein the sloping plate member is spaced a predetermined distance below said deck and mounted between the lower edges of said girder plates so that said plate member serves as the bottom of said channel. 7· A vessel as set -forth in claim k wherein the inboard wall of each wing tank is disposed at an angle to the deck and has a vertical leg connected to said deck and a horizontal leg connected to the side of the hull. 8. A vessel as set forth in any one of the preceding elaims wherein each said wing tank has an Inboard side with a vertical leg connected to said deck, a horizontal leg connected to the side of said hall and a downward and outward sloping central plate connected between said vertical and horizontal legs* a vertical transverse structural bulkhead mounted in each wing tank and having an opening therein, and having its peripheral edge connected to the hull9 deck and inboard wall so as to provide 9* A vessel as set forth in claim 8 wherein said restricting plate is integral with said inboard wall and has the same profile thereof, the openings therein being spaced from each other and arranged in two columns, the are o each said opening decreasing in regards to its position from t&p to bottom of said restricting late* 1Θ. A bulk carrier Vessel substantially as hereinbefore described and illustrated with reference to the accompanying drawings. Attorney for Applicants