US3256848A

US3256848A - Ship stabilizer

Info

Publication number: US3256848A
Application number: US404058A
Authority: US
Inventors: Kenneth C Ripley
Original assignee: John J Mcmullen Associates Inc
Current assignee: John J Mcmullen Associates Inc
Priority date: 1964-10-15
Filing date: 1964-10-15
Publication date: 1966-06-21
Anticipated expiration: 1983-06-21
Also published as: NL6513186A; GB1076220A; ES318536A1; GB1075836A; BE670983A; CA922174A; DE6604717U; NO118955B; SE351186B; FI43953B; DE1531641A1; DE1290053B; FI43045B; SE359787B

Description

June 21, 1966 K. c. RIPLEY 3,256,848

SHIP STABILIZER Filed Oct. 15, 1964 4 Sheets-Sheet 1 Fig.

Fig. 2 I? g 3 4 l2 l6 INVENTOR Kennel/r Clay Ripley ATTORNEYJ' June 21, 1966 K. c. RlPLEY 3,256,843

SHIP STABILIZER Filed Oct. 15. 1964 4 Sheets-Sheet 5 Fig. 9 /4 Jim INVENTOR Kennel/1 Clay R/p/ey BEQWWJWKAI, @41/ A ORNEYS June 21, 1966 K. c. RIPLEY 3,256,848

SHIP STABILIZER Filed Oct. 15, 1964 4 Sheets-Sheet 4 Fig. /2

I III I,

l2 l6 INVENTOR Kenneth Clay Ripley WJM ATTORNEYS United States Patent 3,256,848 SHIP STABILIZER Kenneth C. Ripley, Washington, D.C., assignor to John J.

McMullen Associates, Inc., New York, N.Y., a corporation of New York Filed Oct. 15, 1964, Ser. No. 404,058 1 Claim. (Cl. 114-125) This invention is a modification and a continuation-inpart of the copending application entitled Ship Stabilization, United States Serial No. 201,476, filed June 11, 1962, now Patent No. 3,160,136, which has the same inventor and assignee as the present invention.

This invention relates to a passive ship stabilization system and more particularly a passive ship stabilization system which comprises an elongated liquid storage means and a horizontal flat plate mounted below the static liquid surface within said liquid storage means.

It is an object of the present invention to provide an elongated liquid storage means which is adapted to be mounted athwartship and contain a body of liquid which imparts a stabilizing moment to the ship in response to the roll thereof.

It is another object of the present invention to incorporate a horizontally disposed flat plate that extends the full transverse dimension of said elongated liquid storage means but is spaced from either end of said storage means and is mounted even with or below the surface of liquid within said storage means,

It is yet another object of the present invention to mount an upstanding member at either end of said horizontally disposed fiat plate. a

It is still a further object of the present invention to provide a throttled and dampened passage for liquid and an unthrottled, undampened passage for air enabling liquid and air to be transferred from one side of said longitudinal storage means to the other.

-It is another object of the present invention to provide selectively adjustable means for varying the cross-sectional area of liquid flow beneath the horizontal plate member so that the volume of transferred liquid, and thus the magnitude of the stabilization moment, can be controlled.

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 sectional view illustrating the hull of the ship and illustrating one example of the location of the elongated liquid storage means;

FIG. 2 is a top plan view of one embodiment of the present invention with the top of the elongated liquid storage means removed;

FIG. 3 is a front elevation taken in section along line 3-3 of FIG. 2;

FIG. 4 is a side elevation taken in section along line 44 of FIG. 3;

FIGS. 5, 6 and 7 are front elevations taken in section of other and further modifications of the present invention;

FIG. 8 is a side elevation taken in sect-ion along line 8-8 of FIG. 7;

FIG. 9 is a front elevation taken in section of one of the prior embodiments of the invention incorporating liquid transfer control means;

FIG. 10 is a top plan taken in section along line 1010 of FIG. 9;

FIG. 11 is a front elevation of one of the embodiments of the present invention incorporating yet another liquid transfer control means;

FIG. 12 is atop plan taken in section along line 1212 of FIG. 11;

FIG. 13 is a top plan of one of the embodiments of Patented June 21, 1966 control means; and

FIG. 14 is a front elevation taken along line 1414 of FIG. 13.

Referring now to FIG. 1, there is illustrated generally a vessel 10 having an elongated liquid containing means 12 mounted athwartship therein. Liquid containing means 12 could be preferably a series of welded side and end plates mounted between two

decks

14 and 16 of ship 10, said decks forming the top and bottom of said containing means 12. Tank 12 has a longitudinal dimension which is substantially greater than the transverse dimension thereof. Tank 12 is further characterized by the fact that it has a substantially uniform width and uniform height throughout the longitudinal dimension thereof.

Mounted transversely and spaced from ends 15 of tank 12 are two horizontally disposed, elongated members 20 spaced from the bottom 16 and top 14 of tank 12; said members20 cooperate with ends 15 to form wing tanks at the respective ends of tank 12. The transverse members 20 have lower ends disposed beneath the static liquid level of the liquid body within tank 12. Therefore, transverse members 20 cooperate with bottom 16 of tank 12 to form elongated submerged horizontal nozzles 22 which throttle or dampen the liquid moving therethrough. A horizontally disposed flat plate mounted between the sides of tank 12 is mounted between the transverse members 20. The function of this plate 18 is to prevent liquid from spilling over the transverse members 20 during certain portions of the cycle of roll and also to provide pressures which counteract positive and negative pressures acting on the liquid between transverse members 20 during certain portions of the cycle of roll. Thus, the effects of transfer and damping liquid are somewhat different from, that set forth in my co-pending application mentioned above.

In the embodiment shown in FIG. 3, the transverse members 20 have their upper extremities slightly above the static liquid surface of the body of liquid Within tank 12. The operation of this embodiment will now be described. Referring now to FIGS. 1,2, 3 and 4, as the right side of the hull 10 as seen in FIG. 1 is lowered and the left side is raised, there is an accumulation of liquid mass at the right side of tank 12 as seen in FIG. 3. As the roll of the ship continues and the right side of bull 10 begins to rise to the horizontal position, the accumulation of liquid at the right side of tank 12 imparts a stabilization moment to the ship and opposes roll.

-As the right side of hull 10 continuesto rise through transfer toward the left side of tank 12. Due to the sub v merged horizontal nozzle restrictions 22 formed by bottom 16 and transverse members 20, the volume of liquid transferred is limited to some predetermined value. Because of the rigid construction and mounting of horizontal plate 18, said plate 18 counteracts negative and positive pressures built up on the liquid during certainportions of the cycle of liquid transfer from one side of the stabilization system to the other.

When the left side of hull 10 is in its lowermost position, the velocity of fluid transfer is maximum toward the left side of tank 12. As the left side of hull 10 begins to rise toward the horizontal, accumulated liquid mass at the left side of tank 12 imparts a stabilization moment to the vessel again in opposition to roll. As the left side of hull 10 rises through the horizontal position, a hydrostatic head is formed at the left side of tank 12 and liquid transfer begins to take place in the opposite direction.

The periodic stabilizing forces will be imparted to the ship as long as the vessel 10 continues to roll.

The liquid within tank 12 can be any suitable type such as sea water, bunker oil, or reserve fuel. The only requirement for the selected liquid is that it has a viscosity sufficiently low enough to freely transfer through the submerged nozzle arrangement 22 defined by transverse members 20 and bottom 16.

Referring now to FIG. 5, there is shown another embodiment of the present invention. It should be understood that like references apply to like structure-in all embodiments herein. Again, tank 12 is defined by bottom 16, top 14, and end plates 15. Horizontal plate 18 is again mounted within tank 12 and spaced from the top and bottom thereofl Plate '18 has ends terminating at points spaced from ends 15 of tank 12. Transverse members 24 are mounted at the extremities of horizontal plate 18, each said transverse member having its upper extremi'ty located above the static liquid level of the body of liquid within tank 12 and slightly below top 14 of tank 12. With this arrangement, the liquid is prevented from spilling over the tops of the transverse members 24 and accumulating on the top surface of horizontal plate 18. Furthermore, the static liquid level at the two ends of tank 12 can be raised without increasing the possibility of spillover without choking off air transfer. As the liquid transfers through horizontally submerged nozzles 22, air is free to transfer between tops 14 and the upper ends of transverse members 24. The operation of the system is the same as that described above with hydrodynamic damping imparted to the liquid by submerged nozzles 22.

Referring now to FIG. 6, there is again illustrated a tank 12 having end plates 15, top '14 and bottom 16 and a horizontal plate 18 disposed therein. Again, plate 18 has its longitudinal extremities spaced from the end plates 15. Upstanding transverse members 26 extend from the ends of horizontal plate 18 to the top 14 of tank 12. At least two holes 28 are provided in top 14 to enable the wing tanks to communicate with the atmosphere in response to the liquid transfer from one end of tank 12 to the other. Again, horizontal nozzles 22 hydrodynamically dampen the transferring liquid, and the air above the static liquid surface freely communicates with the ambient.

FIGS. 7 and 8 illustrate another embodiment of the present invention and there is again shown a tank 12 having end plates "15, top 14, bottom 16 and horizontally disposed plate 18. Mounted at the longitudinal ends of plate 18 are two upstanding transverse members 30 which extend from plate 18 to the top 14 of tank 12. Transverse members 30 are characterized by the fact that each has an elongated slot or hole 32 substantially at the top thereof. An elongated duct or pipe 34 is mounted between the pair of holes 32 in transverse member 30 so that air freely communicates therethrough from one end of tank 12 to the other in response to the movement of liquid therein.

This arrangement allows for a damped passage for liquid through horizontal submerged nozzles 22 and an undamped passage for air through the connecting duct 34. The operation of the system is the same as described above.

It should be recognized that the magnitude of the forces imparted to the vessel is' dependent upon the volume or amount of liquid transfer from one side of the stabilizer to the other. It should also be recognized that because of the existence of plate 18, which confines the surface of the liquid within the interconnection passage between the two wing tanks, the volume or amount of liquid transfer per unit time cannot be controlled to any substantial degree by merely changing the liquid level within the respective wing tanks. Therefore, some other control means is incorporated to control the amount or volume of liquid transfer taking place between the wing tanks so that the magnitudes of the forces and stabilizing moment imparted to the vessel can be controlled. I

Referring now to FIGS. 9 and 10, there is illustrated one example of control means which vary the cross-sectional area of flow under plate 18 so that a predetermined rate of liquid transfer can be selected. In this embodiment, at least one side of tank 12 is provided with a vertical slot extending from the bottom 16 of tank 12 to the vertical location of plate 18. This slot 36 can be sealed by any conventional means (not shown). Slidably mounted within slot 36 is an elongated plate valve or gate 38 .which is adapted to be slidably inserted to any position across the transverse dimension of tank 12.

If the conditions of the vessel and sea are such that a small moment is to be imparted to the vessel, gate 38 will be inserted to some predetermined position across the transverse dimension of tank 12 so that the cross-sectional area of liquid flow is substantially reduced. With this reduction of cross-sectional area of liquid transfer, transfer of liquid during one-half cycle of roll is made small. Conversely, if it is desired to have a greater stabilizing moment imparted to the vessel, gate 38 will be withdrawn to increase the cross-sectional area of liquid transfer through that portion of the system beneath plate 18.

Referring now to FIGS. 11 and 12, another type of control means is illustrated therein. In this embodiment, a butterfly valve or rotatably mounted plate 40 is disposed substantially in the center of the system. The angular position of butterfly valve 40 is controlled by a vertically mounted shaft 42 and a conventional hand wheel 44 or the like. When a large liquid transfer is desired within the stabilization system, the hand wheel and consequently the butterfly valve 40 is rotated so that the valve 40 assumes the position shown in phantom in FIG. 12. With the valve 40 in this position, the greatest cross-sectional area of liquid transfer is provided for the stabilization system. If a smaller liquid transfer is desired for the stabilization system, valve 40 is rotated by hand wheel 44 and shaft 40 to the position shown in solid in FIG. 12 so that the cross-sectional area of liquid transfer is substantially reduced.

Referring now to FIGS. '13 and 14, yet another embodiment of the present invention is disclosed therein. In this embodiment, the control means comprises a horizontal, transverse slot mounted in plate 18 which is adapted to receive a transverse gate or plate 46. The transverse slot in plate 18 is provided with the conventional sealing means (not shown) to prevent liquid leakage in the usual manner. Gate 46 is adapted to assume any vertical position with respect to plate 18 so that when it is desired to have a small liquid transfer within the stabilization system, plate 46 would be inserted to a lower position with respect to 18 so that the cross-sectional area of liquid transfer within the system is substantially reduced. If it is desired to have a greater liquid transfer within the system, plate 46 is upwardly withdrawn so that the cross-sectional area of liquid transfer is increased.

Therefore, it can be seen that an eflrcient stabilization system results which is adapted to control the magnitude of stabilization forces imparted to the vessel.

It is to be understood that other and further modifications can be made to the present invention without departing from the spirit thereof.

What is claimed is:

A passive ship stabilizer comprising an elongated liquid storage means having a longitudinal dimension greater than its transverse dimension, said storage means having a uniform transverse dimension throughout the length thereof, a body of liquid partially filling said liquid storage means and having a static liquid level spaced from .the top and bottom of said liquid storage means, at least a port-ion of said static liquid level being in a free surface condition, a pair of transverse members vertically disposed and vmounted across said transverse dimension of said liquid storage means, said transverse members spaced from each other and from the ends of said liquid storage means to form wing tanks and an interconnecting tank therewith, each said transverse memberhaving a lower end spaced from the bottom of said liquid storage means to form a horizontal nozzle, said horizontal nozzle disposed below said static liquid level, a horizontal plate spaced from the top and bottom of said storage means and engaging said transverse members above the lower ends thereof, said horizontal plate extending laterally to the walls of said interconnecting tank to restrict the liquid surface therein, said wing tan ks defining air passage means for enabling an unthrottlcd passage for air, and said stabilizer further comprising a vertical plate member below said horizontal plate movable with respect to said storage means and having vertical edges which define with the Walls of said storage means two adjustable vertical openlngs, extending from the floor of the storage means up to the horizontal plate, whereby said plate provides an abrupt discontinuity in the uniform cross-sectional interconnecting tank, and vertical shaft extending through the top of said storage means and said horizontal plate and terminating at its upper end with a device for rotating said shaft about its longitudinal axis, the lower end of said shaft being mounted to the vertical centerline of said vertical plate so that said shaft is rotatable by said shaft about a vertical axis defined by said shaft, said vertical plate having a horizontal dimension greater than its height and said horizontal dimension being less than the transverse dimension of said storage means, whereby the effective local cross-section area of about the center of said interconnecting tank is selectively adjustable by changing the vertical plate setting between a position in which said vertical plate is parallel to the fore and aft plane and a position in which it is perpendicular to the fore and aft plane.

References Cited by the Examiner UNITED STATES PATENTS 2,077,143 4/1937 Carroll 114125 3,083,672 4/1963 Ripley 114125 3,083,674 4/1963 Ripley 114-425 3,103,198 9/1963 Ripley 114-425 OTHER REFERENCES Ser. No. 132,695, Hort (APC), pub. May 11, 1943. German .printed application No. 1,153,283, August MILTON BUCHLER, Primary Examiner.

FERGUS S. MIDDLETON, Examiner.

T. M. BLIX; Assistant Examiner.