US3380423A - Ship stabilizer - Google Patents

Ship stabilizer Download PDF

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Publication number
US3380423A
US3380423A US539169A US53916966A US3380423A US 3380423 A US3380423 A US 3380423A US 539169 A US539169 A US 539169A US 53916966 A US53916966 A US 53916966A US 3380423 A US3380423 A US 3380423A
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US
United States
Prior art keywords
tank
members
liquid
ship
stabilizer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US539169A
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English (en)
Inventor
Sheldon B Field
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
John J Mcmullen Associates Inc
Original Assignee
John J Mcmullen Associates Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by John J Mcmullen Associates Inc filed Critical John J Mcmullen Associates Inc
Priority to US539169A priority Critical patent/US3380423A/en
Priority to FR100689A priority patent/FR1515745A/fr
Priority to BE696282D priority patent/BE696282A/xx
Priority to DE6608516U priority patent/DE6608516U/de
Priority to GB04587/67A priority patent/GB1177386A/en
Priority to ES338685A priority patent/ES338685A1/es
Priority to NL6704669A priority patent/NL6704669A/xx
Application granted granted Critical
Publication of US3380423A publication Critical patent/US3380423A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
    • B63B39/02—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses
    • B63B39/03—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses by transferring liquids

Definitions

  • a passive tank stabilizer housing a liquid body in a free surface condition at all times and having a geometry so as to impart substantially no internal damping to liquid passage.
  • the tank damping coefficient is variable by means of adjustable damping members arranged to define two wing tanks and an interconnecting channel Within the tank. The damping members can be rotated and locked in different angular positions to vary the cross section available for liquid passage so as to adjust the tank damping coeliicient to an optimum value according to the conditions of the tank and the ship at sea.
  • the present invention relates to a passive ship stabilizer and more particularly to an improved stabilizer of the open channel type having selectively movable members or gates the angular positions of which control the amount of damping imparted to the transferring liquid within the tank.
  • One embodiment of the present invention comprises a pair of gates extending vertically and eccentrically mounted on rotating axes.
  • the gates are aligned across the tank and are mutually movable between a lirst position in which they are aligned in the fore and aft direction and a second position in which they extend parallel to the longitudinal axis of the tank.
  • Mechanical means are provided to rotate the gates and lock the same in any angular position between said first and second positions.
  • Another embodiment of the present invention com* prises a plurality of elongated bars having rectangular or square cross sections and each mounted vertically on a rotating axis. Each of two sets of these bars are aligned across the tank near an end thereof, and are spaced from each other to define a plurality of passageways therebetween. The cross-sectional area of each passageway is selectively varied by changing the angular position of the bars.
  • An alternate arrangement comprises the use of elongated plates having rounded edges in lieu of the bars with rectangular profiles.
  • Still another embodiment of the present invention comprises two sets of elonga'ed members spaced from opposite ends of the tank, each member being mounted on a rotating axis.
  • the members are spaced vertically from each other with the axes of rotation being horizontally arranged in the fore and laft direction.
  • FIGURE 1 is a diagrammatic illustration of a ver- 3,380,423 Patented Apr. 30, 1968 ICC tical transverse section of a ship with the stabilizer according to the present invention mounted therein.
  • FIGURE 2 is a horizontal section of the tank taken along line 2-2 of FIGURE 1 and showing one embodiment of the invention.
  • FIGURE 3 is a vertical longitudinal section of the tank taken along line 3 3 of FIGURE 2.
  • FIGURE 4 is a horizontal section illustrating another embodiment of the present invention.
  • FIGURE 5 is a horizontal section of yet another embodiment of the present invention.
  • FIGURE 6 is a vertical longitudinal section of the tank of still another embodiment of the present invention.
  • stabilizer 10 is mounted across the hull 12 of a ship.
  • the longitudinal axis of tank 10 is mounted in a plane perpendicular to the roll axis of the ship.
  • the top and bottom of tank 10 comprises two spaced existing decks of the ship and the ends of tank 12 comprise the sides of hull 12.
  • a pair of transverse bulkheads 14 and 16 are mounted between the decks and extend from one side of the hull to the other to form the enclosed tank. All seams are welded so as to present a watertight enclosure.
  • a pair of elongated gates 18 and 20 are provided in tank 10 at locations spaced from each end of tank 10.
  • Each gate has an elliptical or oval cross section and extends vertically from the top to the bottom of tank 10 and is eccentrically mounted to a vertical shaft 22 and 24 which is journaled or otherwise retained in the top and bottom of the tank.
  • Shafts 22 and 24 are spaced near and equal distance from the longitudinal center axis of tank 10 and are aligned in the fore and aft direction.
  • Gates 18 and 20 have their inner edges connected to shafts 22 and 24 so that the free edges of the gates extend away from the center axis of the tank. If desired, each pair of shafts or all shafts can be mechanically ganged so that the gates move together and assume equal relative positions.
  • shafts 22 and 24 extend above the top of tank 10.
  • a manual or mechanically Ioperated member such as hand wheel 26 or the like is connected to shaft 22.
  • Any suitable locking means is provided to retain shaft 22 in any desired angular position, relative to tank 10.
  • gear 28 is fitted to shaft 22 and finger 30 is rotatably mounted on the top of tank 10. Finger 30 locks shaft 22 when it engages the teeth of gear 28.
  • finger 30 is rotated up and out of engagement with gear 28 so that the new angular setting of shaft 22 can be made.
  • Gates 18 and 20 are rotatable between a first position in which they are aligned fore and aft and a second Iposition in which they are parallel to the longitudinal axis of tank 10. In the first position, gates 18 and 20 cooperate with the walls of tank 10 and with each other to form restricted passageways in the tank. With gates 18 and 20 in this position, a relatively high damping coefficient exists within tank 10, whereas, when gates 18 and 20 are in the second position a relatively low damping coefficient is provided.
  • the damping coeliicient can be suitably changed by rotating gates 13 and 20 to any angular position between said first and second positions.
  • tank 10 is partially filled with a body of liquid so that an air space exists above the liquid throughout the length of the tank.
  • the height of the liquid, and therefore, the mass is selected so that the natural frequency of liquid oscillation is equal to the natural roll frequency of the ship. If the conditions of the ship change, such as having its freight unloaded, the liquid level in tank 10 can be changed so that the roll frequency and the liquid oscillation frequency remain the same.
  • Any suitable liquid such as sea water, bunker oil, fuel, fresh water, or the like, can be used as the stabilizing medium. If desired, heavy density liquid and liquid-solid suspensions can be used as the stabilizing medium.
  • the amplitude of liquid oscillation and consequently the magnitude and phase of the stabilizing movement imparted to the ship is related to the coefficient of damping within tank 10.
  • This coefficient is adjusted by setting gates 18 and 20 at predetermined angular positions relative to tank 10. For example, if a high coefficient of damping is desired, gates 18 and 20 are set and locked in. the aligned fore and aft position so as to present the smallest effective passageway between the end portion and the center portion of the tank. If a lower coefficient of damping is required so that less damping takes place during one cycle of roll, gates 18 and 20 are rotated either clockwise or counterclockwise toward a position in which they are parallel to the longitudinal axis of the ship.
  • elongated members 32 extend from the bottom to the top of tank 10 and each are mounted to a rotating shaft 22.
  • Each member 32 has a square cross section.
  • Members 32 are aligned in the fore and aft direction and are spaced from the walls of tank 10 to form a plurality of passageways therebetween.
  • Each member is rotatable on its axis 22 so that the effec- Itive cross-sectional area of the passageways therebetween can be selectively changed in the manner described above. It can be seen that when the sides of members 32 are perpendicularly arranged with the walls of tank 10, the passageways have a maximum cross-sectional area. However, when members 32 are rotated 45 and locked as described above, the effective cross-sectional area of each passageway is decreased. Again, members 32 can be rotated and locked at any angular position between the t first and second positions.
  • FIGURE 5 illustrates another embodiment of the present invention, wherein elongated upstanding plates 34 are secured to vertical rotating shafts 22 as described above. Plates 34 are spaced from each other in the walls of tank 10, and are aligned in the fore and aft direction. Each plate 32 has a cross section with its width greater than its thickness. Preferably, the edges of plates 34 are rounded, but can be squared off if desired. In one example, each plate 34 is symmetrically mounted on its shaft 22. When the width of each plate 34 is directed in the fore and aft direction, the effective cross-sectional area therebetween is at a minimum, and when the width of each plate 34 extends in the longitudinal direction of tank 10, the passageways have a maximum cross-sectional area. As in the above embodiments, plates 34 can be secured at any angular position between the two above-mentioned positions.
  • FIGURE 6 Yet another arrangement of the present invention is illustrated in FIGURE 6 wherein elongated members 36 are each mounted to a rotatable shaft 22, and wherein members 36 and shafts 22 extend horizontally in the fore and aft direction.
  • Each member 36 is spaced from the other members and from the top and bottom of tank 10 and are aligned in the vertical direction.
  • members 4 36 form with tank 16 a plurality of horizontally extending passageways through which the liquid body transfers.
  • some of the members 36 are located above the static liquid level and some of the members 36 are located below the static liquid level.
  • Each member 36 has a rectangular cross section so that the cross-sectional areas of the passageways is selectively changed when members 36 are rotated and locked in various angular positions relative to tank 10.
  • the operation of the stabilizer shown in FIGURE 6 is the same as mentioned above, however, liquid transfer takes place through submerged and partially submerged horizontal openings near the ends of tank 10.
  • a passive stabilizer for a vessel comprising an elongated tank having its longitudinal axis positioned across the vessel and having a top, a bottom, two side walls and two ends, said tank having a generally rectangular cross section so as to impart insignificant damping to the tank liquid, a pair of elongated members each spaced from an opposite end of said tank and being spaced from each other so that said tank is divided into two end portions and an interconnecting portion, and means for rotatably mounting each said member to said tank and for locking during steady state operation each member in a selected one of a plurality of angular positions relati.'e to said tank so as to adjust the damping imparted to the tank liquid during steady state operation, a body of liquid partially filling said tank such that an air space is defined throughout between the top surface of said liquid and the top of said tank, said tank liquid filled to a level such that the tank liquid oscillation is generally tuned to the ships roll, and said liquid transferring from one end of said tank toward the other in response to the roll of said ship, each said
  • each gate having a profile which is generally elliptical and each gate being eccentrically mounted to said shaft, each gate being movable between a position in which the long dimension of its profile is perpendicular to the longitudinal axis of said tank and a position in which the long dimension of its profile is parallel to the longitudinal axis of the tank.
  • each said member has a square cross-sectional profile.
  • each said member has a profile which is generally rectangular with rounded edges.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Vibration Prevention Devices (AREA)
  • Vehicle Body Suspensions (AREA)
US539169A 1966-03-31 1966-03-31 Ship stabilizer Expired - Lifetime US3380423A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US539169A US3380423A (en) 1966-03-31 1966-03-31 Ship stabilizer
FR100689A FR1515745A (fr) 1966-03-31 1967-03-29 Stabilisateur passif anti-roulis pour navire
BE696282D BE696282A (2) 1966-03-31 1967-03-29
DE6608516U DE6608516U (de) 1966-03-31 1967-03-29 Passives stabilisierungssystem fuer schiffe.
GB04587/67A GB1177386A (en) 1966-03-31 1967-03-30 Ship Stabilizers
ES338685A ES338685A1 (es) 1966-03-31 1967-03-31 Perfeccionamientos en estabilizadores pasivos para buques.
NL6704669A NL6704669A (2) 1966-03-31 1967-03-31

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US539169A US3380423A (en) 1966-03-31 1966-03-31 Ship stabilizer

Publications (1)

Publication Number Publication Date
US3380423A true US3380423A (en) 1968-04-30

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Application Number Title Priority Date Filing Date
US539169A Expired - Lifetime US3380423A (en) 1966-03-31 1966-03-31 Ship stabilizer

Country Status (7)

Country Link
US (1) US3380423A (2)
BE (1) BE696282A (2)
DE (1) DE6608516U (2)
ES (1) ES338685A1 (2)
FR (1) FR1515745A (2)
GB (1) GB1177386A (2)
NL (1) NL6704669A (2)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012346A (en) * 1974-03-09 1977-03-15 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Acrylic synthetic fibers having an animal hair-like touch and its method of manufacture

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112937791B (zh) * 2021-02-23 2022-12-13 江苏中兴水务有限公司 一种防止风浪推翻打渔船及水草缠绕的保护装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2077143A (en) * 1932-01-06 1937-04-13 Firm Of Townsend & Decker Means for stabilizing ships with fuel oil
GB1002788A (en) * 1963-10-08 1965-08-25 Harrison Lackenby Method of and means for reducing the oscillatory motions of ships
US3256848A (en) * 1964-10-15 1966-06-21 Mcmullen Ass John J Ship stabilizer
US3269346A (en) * 1964-03-02 1966-08-30 Muirhead & Co Ltd Passive tank stabilizers for floating bodies

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2077143A (en) * 1932-01-06 1937-04-13 Firm Of Townsend & Decker Means for stabilizing ships with fuel oil
GB1002788A (en) * 1963-10-08 1965-08-25 Harrison Lackenby Method of and means for reducing the oscillatory motions of ships
US3269346A (en) * 1964-03-02 1966-08-30 Muirhead & Co Ltd Passive tank stabilizers for floating bodies
US3256848A (en) * 1964-10-15 1966-06-21 Mcmullen Ass John J Ship stabilizer

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012346A (en) * 1974-03-09 1977-03-15 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Acrylic synthetic fibers having an animal hair-like touch and its method of manufacture

Also Published As

Publication number Publication date
NL6704669A (2) 1967-10-02
FR1515745A (fr) 1968-03-01
GB1177386A (en) 1970-01-14
DE6608516U (de) 1971-10-21
ES338685A1 (es) 1968-08-16
BE696282A (2) 1967-09-29

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