US3160136A

US3160136A - Ship stabilization

Info

Publication number: US3160136A
Application number: US201476A
Authority: US
Inventors: Kenneth C Ripley
Original assignee: John J Mcmullen Associates Inc
Current assignee: John J Mcmullen Associates Inc
Priority date: 1962-06-11
Filing date: 1962-06-11
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08

Description

Dec. 8, 1964 K. c. RlPLEY SHIP STABILIZATION 3 Sheets-Sheet 1 Filed June 11, 1962 I INVENTOR Kennel/k fig ley ORNEYS m 9% w m 3 Sheets-Sheet 2 INVENTOR Kenneth 6f Rz 'uZeg AgTORNEYS Dec. 8, 1964 K. c. RIPLEY SHIP STABILIZATION Filed June 11 1962 Dec. 8, 1964 K. c. RIPLEY SHIP STABILIZATION 5 Sheets-Sheet 5 Filed June 11, 1962 mflw ATTORNEYS +3 INVENTOR KemzeZ/z 63 Qb' vley if a United States Patent 3,160,136 SHIP STABILIZATION Kenneth C. Ripley, Washington, D.C., assignor to John J.

McMulien Associates, Inc., New York, N.Y., a corporation of New York Filed June 11, 1962, Ser. No. 201,476

10 Claims. (Cl. 114-125) The present invention relates to improvements in ship stabilization and, more particularly, to improvements in the novel passive stabilization system invented by me and forming the subject of my earlier copending application Serial No. 9,144, entitled Flume Type Heeling Tank Stabilizer, filed February 16, 1960, now Patent No. 3,054,373.

With the advent of my novel passive stabilization system for ships to stabilize them against roll, as described in my earlier copending application as identified above, an entirely new concept in ship stabilization was presented to the art. Since the earlier invention, I have developed improvements and refinements to the original concept and these will be described in the following.

It is an object of the present invention to provide improvements in the passive ship stabilization system previously invented by me which will enable this system to operate more effectively and more efficiently.

It is a further object of the present invention to provide improvements to my passive stabilization system wherein surging in the crossover duct will be reduced and eliminated for all intents and purposes.

It is a still further object of the present invention to provide an improvement to my passive stabilization system wherein the transfer of liquid in the system is effected through horizontally arranged nozzle openings.

It is a still further object of the present invention to provide an improvement to my passive stabilization system wherein specially designed surge plates are located inthe nozzles whereby the transfer of liquid will be conducted more efiicaciously.

Other and further objects of the present invention will become apparent from the following detailed description of preferred embodiments of the improvements when taken in conjunction with the drawings, in which:

FIGURES 1 to 4 illustrate diagrammatically an improvement wherein horizontal nozzles are employed;

FIGURES 5 and 6 illustrate diagrammatically the use of surge disruptive means in the crossover duct in conjunction with the improvement of horizontally arranged nozzles;

FIGURES 7 and 8 illustrate diagrammatically the action occurring at the horizontal nozzle in two different cases; and

FIGURES 9 and 10 illustrate the improvement of utilizing surge plates in conjunction with vertically arranged nozzles.

Referring now to the drawings, the improvements will be described in detail. In the following description, it will be appreciated that the only parts which have been shown are those relating specifically to the stabilization system itself. Basically, the stabilization system is comprised of a rectangular box which is positioned in a ship or other watergoing craft transversely to the long axis of "ice The system as portrayed in FIGURES 1 to 4 is comprised of a rectangular box It closed on all sides and having a long dimension slightly less than the width of the ship within which the system is to be installed so that it will extend from one side to the other. Positioned within the box 10 are two plates 12 spaced from opposite ends of the box It and also spaced from the top and bottom of the box It). The plates 12'are rounded at their top and bottom and thus provide, in conjunction with the bottom of the box 10, nozzle openings identified in FIG- URE 2 by the reference numeral 14.

In the practice of the improvement illustrated in FIG- URES 1 to 4, liquid identified by the reference numeral 16 is placed in the box 10 to the level of the top of the plates 12. When the ship tends to roll from side to side the liquid that is present between one of the plates 12 and the respective end of the box 10 will tend to be transferred toward the opposite end of the box. This condition is generally illustrated by FIGURES 3 and 4 wherein the ship is shown rolling to the left. Therefore, the left end of thebox It is brought to a lower elevation than the right end of the box 10. During this movement the liquid between'the plate 12 and the right end of the box It passes through the nozzle opening 14 toward the left end of the box 10. At the left end, the liquid is passing through the nozzle opening 14 into the left end of the box and also is passing over the plate 12 into the left end of the box. The final condition is generally illustrated by FIGURE 4 wherein a height of liquid equivalent to H above the top of the plate 12 is present in the left end of the box 10. When the ship rolls toward the right the liquid in the left end of the box It) will flow through the nozzle opening 14 and also over the plate 12 transferring toward the right end of the box Hi. This sequence will be repeated so long as sufiicient impetus is afforded by rolling I i of the vessel. Remarkably, despite the simplicity of the arrangement, the transfer of the liquid will be in phase opposition with the rolling of the box It) and ship and, consequently, a stabilizing moment will be produced which will reduce the roll. The top of the plates 12 in elfect function as weirs.

A further improvement is illustrated in FIGURES 5. and 6 wherein the box It, in this instance, is provided with tubular structures 20 which extend *horizontally across the box 10 at either end thereof but spaced from the ends. The tubular structures are each composed of a pipe or tube 22 which is located spaced from the bottom of the box 10 and a tubular projection 24 which is attached to the top of the pipe 22 and extends vertically. Again, liquid 16 is placed in the box 10 to the top of the projections 24.

Mounted in the central part of the box 10 between the tubular structures 20 are a series of vertical tubes 26. These tubes 26 are arranged in two rows and the tubes in each row are spaced apart from each other. The net effect of the tubular structures in the mid-portion of the box 10 is to provide vertical nozzle openings 28 to reduce surging in the box It in that portion thereof which lies between the tubular structure 20. It will be appreciated that the box It? will be quite long depending upon the width of the ship in which the system is being mounted.

In order to prevent undue Wave action in that portion of the box III which lies between the tubular structures 29, the tubes 26 which define the series of certical nozzle openings 28 will effectively inhibit undue wave action.

The tubes 22 are spaced from the bottom of the box 10 and define nozzle openings 3%) which function in a similar manner as the nozzle openings 14 as described in conjunction with FIGURES 1 to 4. It is possible, however, that the flow through the nozzle openings 30 can be controlled, at least to the extent of providing a vena contracta in certain instances. The way that this would be accoma plished is illustrated by FIGURES 7 and 8. If the Throat of the nozzle opening 30 is approximately 7 of the distance from the bottom of the box 10 to the center of the tube 22 .the fiow of liquid through the nozzle opening 30 v will be streamlined and the point of smallest diameter of the flow will be at the Throat of the .nozzle opening'30 as indicated by the legend in FIGURE 7.

If it is desired to move the Throat or smallest diameter of flow laterally spaced from the nozzle opening 30," this can readily be accomplished by a tubular structure as illustrated in FIGURE 8. In this instance, the nozzle opening is greater than 6/ the distance from the "bottom of the box 10 to the center of tube 22. Consequently, the flow pattern of the liquid passing through the opening 30-will be such that a vena contracta will be established. Therefore, the point of smallest diameter in the flow path will be laterally spaced to the left or right of the opening.

30 as indicated by the legended Throat or corresponding fiow lines as indicated in FIGURE 8.

FIGURES 9 and 10 illustrate an improvement wherein vertically arranged nozzle openings are provided for both the end tubular structures as well as the central tubular openings. As described in conjunction with FIGURESS and 6 two rows of tubes 26 are provided in the mid-portion of thebox 10 to establish'a plurality of vertically arranged nozzle openings 28.

The side tubular structures, rather than establishing horizontal nozzle openings, establish vertical nozzle openings. The side tubular structures are provided by a cen-.

tral tube 34 which extends from the bottom of the box Him the top,-approximately midway from either side,

and end tubes 36 which also extend from the-bottom of the box 10 to the top with eachprojecting from one of the side walls. The side tubes 36 define with the center tube 34 two vertical nozzle openings 38. A pair of

surge plates

40 and 42 are mounted from side to side in the box 10 in the plane of the nozzle. openings 38. Both plates are horizontally positioned and vertically spaced with'the plate 40 being slightly narrower than the plate 42. The plate 42is spaced from the bottom of the box 10 and the plate 40 is spaced belowthe surface of the liquid 16. con-. tained within the box10approximately to the half-Way. The edges of the plates 40 and'42 are rounded or. curled as indicated by the reference numeral 44. The principal advantage of the

plates

40 and 42. is to effect the transfer of liquid. through the nozzle openings 38 in a more efiicient manner.

As noted previously, the box structure 10 is located in a ship to be stabilized-transversely of the long axis of the ship with the box 10 being positioned horizontally. As the ship tends. to roll from sidet'o side the liquid 16 con tained in the box 10is transferred-from-one side of the box 10 to, the other side and in the process is caused to flow through nozzle openings as de'scribed.- The flow through the nozzle openingsprcduces an energy-dissipating reaction and the transfer of the liquid to other nozzle structures is conducted to bein phase opposition'to the rolling motion of the ship. Therefore, stabilizing moments are created by the transfer of the liquid in the box 10 which oppose the rolling impetus being imparted to the. ship and, therefore, stabilization is effected.

Although the present invention has been shown and described in terms of specific preferred embodiments, it is appreciated that changes and modifications-are possible whichdo not depart from the inventive concept. Such changes and modifications are deemed tocorne within the spirit and purview of the invention.

What is claimed is: I

'1. In combination with a water going vessel, a passive stabilization system therefor comprising a tank having a longitudinal axis mounted transversely in said vessel, a pair of members extendingtransversely across said tank near opposite ends thereof and spaced from the top and bottom thereof to define therewith horizontally elongated restrictions,'a body of liquid partially filling said tank, said' body having the same static level throughout the substantially entire .tank, said tank adapted to enable air to be freely transferred from one side of said tank to the other in response to the movement of fluid therein, whereby the energy of fluid transfer within said tank is hydrodynamically'damped only,- and wherein at least one of said restrictions is disposed belowsaid static liquid level.

2. A passive stabilization'system as set forthin claim 1, wherein said pair of transverse members are positioned to'enable fluid to flow both over and under each of said of. for defining vertical restrictions, and wherein said trans verse members comprise plate means extending transversely'across said tank in a horizontal plane, said plate means mounted on'said means defining vertical restric-' tions, and positioned below the static liquid level of said tankand spaced 'from the bottom of said tank.

6. The combination recited in claim 2 wherein said members have rounded lower edges.

7. The combination recited in claim 2 wherein the top edges of said members terminate at the surface of said body of liquid.

8. The combination as recited in claim 2 further 'including tubular means extending from top to bottom in said enclosure in the mid-portion'thereof and defining'a plurality of vertical restrictions;

9. The combination recited in claim 5 wherein said plate means. is comprised of a pair of vertically spaced plates having rounded edges.

10. The combination recited in claim 5 further includingtubular means extending from top to bottom in said enclosure'in the mid-portion'thereof defining a plurality of vertical restrictions.

References Cited in the file of this patent UNITED STATES PATENTS 1,007,348 Frahm Oct. 31, 1911 1,023,477 I Oldham Apr. 16, ,1912

FOREIGNPATENTS 435,100 Great Britain Sept. 13, 1935 688,796 Germany Mar. 2, 1940 731,246 Germany Feb. 4, 1943 1,036,894 France Apr. 29, 1953 OTHER REFERENCES Ser. No. 132,695,.H'0rt (A.P.C.), published May 11, 1943.

Claims

1. IN COMBINATION WITH A WATER GOING VESSEL, A PASSIVE STABILIZATION SYSTEM THEREFOR COMPRISING A TANK HAVING A LONGITUDINAL AXIS MOUNTED TRANSVERSELY IN SAID VESSEL, A PAIR OF MEMBERS EXTENDING TRANSVERSELY ACROSS SAID TANK NEAR OPPOSITE ENDS THEREOF AND SPACED FROM THE TOP AND BOTTOM THEREOF TO DEFINE THEREWITH HORIZONTALLY ELONGATED RESTRICTIONS, A BODY OF LIQUID PARTIALLY FILLING SAID TANK, SAID BODY HAVING THE SAME STATIC LEVEL THROUGHOUT THE SUBSTANTIALLY ENTIRE TANK, SAID TANK ADAPTED TO ENABLE AIR TO BE FREELY TRANSFERRED FROM ONE SIDE OF SAID TANK TO THE OTHER IN RESPONSE TO THE MOVEMENT OF FLUID THEREIN, WHEREBY THE ENERGY OF FLUID TRANSFER WITHIN SAID TANK IS HYDRODYNAMICALLY DAMPED ONLY, AND WHEREIN AT LEAST ONE OF SAID RESTRICTIONS IS DISPOSED BELOW SAID STATIC LIQUID LEVEL.