US3270702A - Ship stabilizer comprising weirs - Google Patents

Ship stabilizer comprising weirs Download PDF

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Publication number
US3270702A
US3270702A US386187A US38618764A US3270702A US 3270702 A US3270702 A US 3270702A US 386187 A US386187 A US 386187A US 38618764 A US38618764 A US 38618764A US 3270702 A US3270702 A US 3270702A
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US
United States
Prior art keywords
ship
stabilizer
fluid
weir
tank
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
US386187A
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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 US386187A priority Critical patent/US3270702A/en
Priority to NL6509887A priority patent/NL6509887A/xx
Priority to GB32803/65A priority patent/GB1070508A/en
Priority to NO159140A priority patent/NO122821B/no
Priority to DE19651456266D priority patent/DE1456266B1/de
Priority to FI1845/65A priority patent/FI43689B/fi
Application granted granted Critical
Publication of US3270702A publication Critical patent/US3270702A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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

  • Ballast tanks connected by piping and the like have been employed in order to transfer water in a manner to generate a restoring moment. Such systems encounter the diflicu-lty of maintaining the proper phasing between the restoring moment and motion imparted to the ship. Efforts to employ volumes of air above liquid ballast for controlling the ballast have resulted in massive systems which are uncertain as well as excessively noisy in operation. Efforts have also been directed to providing the ship with fin members extending from the hull beneath the water line and adapted to generate restoring moments from the hydrodynamic forces on the fins accompanying the motion of the ship. In certain applications controlled fins have been effective in controlling the roll of the ship but only with the expense of complex systems employing massive fin members and operating machinery. Furthermore, controlled fins are generally effective only when the ship is underway and therefore cause drag resulting in a loss of ship speed.
  • Another object of the invention is to provide a ship stabilizer which is passive in operation but which is adapted to be conveniently adjusted to compensate for changes in the condition of the ship or the sea.
  • a still further object of the invention is to provide a ship stabilizer which is relatively compact and of reasonable weight.
  • a further object of the invention is to provide a ship stabilizer which damps the movement of fluid therein so that better stability can be imparted and the degree of roll of the ship is held to a minimum.
  • the ship stabilizer 3,270,702 Patented Sept. 6, 1966 comprises a tank containing a quantity of fluid having a free surface.
  • the longitudinal axis of the tank is adapted to extend substantially horizontally and substantially at right angles to the axis about which the ship is to be stabilized.
  • the tank is disposed in a substantially athwar-tship direction along one of the decks of the ship.
  • a plurality of weirs or hydraulic jumps are mounted in the bottom of the ship at substantially right angles to the direction of movement of fluid within the tank.
  • FIGURE 1 is a vertical sectional View of a ship showing the arrangement of the ship stabilizer
  • FIGURE 2 is an enlarged plan view of one embodiment of the stabilizer
  • FIGURE 3 is a vertical section view of the stabilizer taken along lines 33 of FIGURE 2;
  • FIGURE 4 is a perspective view of the stabilizer shown in FIGURES 2 and 3.
  • FIGURE 1 a ship stabilizer generally indicated as stabilizer 10 mounted athwartship below decks 12 of the ship 14. It can be seen,'when the stabilizer 10 is partially filled with fluid, said stabilizer can perform passive stab-ilization whenever roll forces are applied to the ship 14.
  • the stabilizer comprises a tank 16 formed by sides 18 and 20 and ends 22 and 24.
  • the tank 16 can have a top to prevent fluid spill or the sides can extend between two decks, thus using the upper deck as a top. By extending the stabilizer across the hull of ship 14 the maximum moment arm of the liquid can be obtained.
  • the stabilizer is proportioned in a manner such that the weight of the liquid which is displaced in a position adjacent an end portion thereof is suflicient to generate a restoring moment capable of restoring the motion of the ship for a range of sea conditions.
  • the fluid within the tank has a free surface and can move in response to the motion of the ship. It can be seen, however, that once the moment force is created by the liquid to oppose the roll of the ship, the fluid mass velocity increases so that the fluid mass begins to move across the tank to the opposite end thereof. As will be described below, a portion of the kinetic energy of the moving mass will be absorbed by the hydraulic jumps or weirs 216 and 2 8 so that a large reflected wave will not result.
  • the upstanding weirs 26 and 28 are mounted perpendicular to the direction of flow of the fluid within the tank and also function to impede or dampen the flow of fluid therein.
  • the fluid to be employed within the stabilizer can be any liquid or the like having suflicient density and with a viscosity of a sufliciently low magnitude so that flow can readily take place within tank 16.
  • Liquids such as sea water, fresh water, bunker oil or types of liquid cargo can be used in the stabilizer tank.
  • the potential energy of the fluid in end portion 34 is converted into kinetic energy as the fluid mass begins to flow over weir 26 toward end portion 36.
  • the fluid continues to flow in the direction of end portion 36 due to its kinetic energy.
  • there is an accumulation of fluid in end portion 36 as the portion of the hull adjacent thereto attempts to be elevated by the sea or rolling forces.
  • a portion of the kinetic energy thereof is absorbed by the weir or jump 2 8, and also, an impedance to a reflected wave is also imparted to the fluid by said weir 28.
  • weir 28 prevents an immediate reversal of fluid flow as side 32 of the ship rises so that fluid can present a restoring moment in opposition to the rising side 32. This process then continues so long as sea forces are applied to the bull to cause it to move about and roll about the axis of the ship.
  • Said cross section can be triangular, rectangular, trapezoidal, or any other desired shape.
  • weir 276 and height of Weir 28 can be made adjustable by any conventional means in accordance wit-h the desired liquid level present in tank 16 without departing from the spirit of this invention.
  • a ship stabilizer comprising an elongated containing means partially filled with a liquid body, the top surface of which is in a free surface condition, said containing means having a bottom, sides and a longitudinal axis, said containing means including two upstanding weir means each mounted off-center toward opposite ends within said containing means, said weir means having a height less than that of said sides, said weir means disposed substantial-1y perpendicular to said longitudinal axis and contacting said sides and said bottom of said containing means, and that portion of said containing means between said two weir means comprising a substantially unobstructed flume.
  • said elongated containing means comprises a substantial flat bottom, two vertical uniplanar sides, and two ends; said bottom, two sides and two ends forming a flume tank of a substantially constant cross-section throughout.
  • said flume tank includes only said two weir means mounted transverse said longitudinal axis and olf-center toward opposite ends of said tank, said weir means spaced from said two ends and from each other.
  • said two weir means comprise two upstanding plates in contact relation with said bottom and said sides of said tank, and wherein the tops of said plates have rounded edges.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Vibration Prevention Devices (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
  • Vehicle Body Suspensions (AREA)
US386187A 1964-07-30 1964-07-30 Ship stabilizer comprising weirs Expired - Lifetime US3270702A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US386187A US3270702A (en) 1964-07-30 1964-07-30 Ship stabilizer comprising weirs
NL6509887A NL6509887A (de) 1964-07-30 1965-07-30
GB32803/65A GB1070508A (en) 1964-07-30 1965-07-30 Passive-tank ship stabilizer
NO159140A NO122821B (de) 1964-07-30 1965-07-30
DE19651456266D DE1456266B1 (de) 1964-07-30 1965-07-30 Passive Schiffsstabilisierungsanlage
FI1845/65A FI43689B (de) 1964-07-30 1965-07-30

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US386187A US3270702A (en) 1964-07-30 1964-07-30 Ship stabilizer comprising weirs

Publications (1)

Publication Number Publication Date
US3270702A true US3270702A (en) 1966-09-06

Family

ID=23524535

Family Applications (1)

Application Number Title Priority Date Filing Date
US386187A Expired - Lifetime US3270702A (en) 1964-07-30 1964-07-30 Ship stabilizer comprising weirs

Country Status (6)

Country Link
US (1) US3270702A (de)
DE (1) DE1456266B1 (de)
FI (1) FI43689B (de)
GB (1) GB1070508A (de)
NL (1) NL6509887A (de)
NO (1) NO122821B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4697458A (en) * 1986-11-21 1987-10-06 Billstein Herbert H Crane load-test gauge

Citations (5)

* 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
DE688796C (de) * 1938-05-13 1940-03-02 Siemens App Tankstabilisierungsanlage
US3083674A (en) * 1961-10-13 1963-04-02 Mcmullen Ass John J Linear-response flume stabilizer
US3083672A (en) * 1960-10-25 1963-04-02 Mcmullen Ass John J Stabilization system
US3160136A (en) * 1962-06-11 1964-12-08 Mcmullen Ass John J Ship stabilization

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3054373A (en) * 1960-02-16 1962-09-18 Mcmullen Ass John J Flume type heeling tank stabilizer
US3083673A (en) * 1960-10-25 1963-04-02 Mcmullen Ass John J Passive stabilization system

Patent Citations (5)

* 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
DE688796C (de) * 1938-05-13 1940-03-02 Siemens App Tankstabilisierungsanlage
US3083672A (en) * 1960-10-25 1963-04-02 Mcmullen Ass John J Stabilization system
US3083674A (en) * 1961-10-13 1963-04-02 Mcmullen Ass John J Linear-response flume stabilizer
US3160136A (en) * 1962-06-11 1964-12-08 Mcmullen Ass John J Ship stabilization

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4697458A (en) * 1986-11-21 1987-10-06 Billstein Herbert H Crane load-test gauge

Also Published As

Publication number Publication date
DE1456266B1 (de) 1970-12-17
NO122821B (de) 1971-08-16
NL6509887A (de) 1966-01-31
FI43689B (de) 1971-02-01
GB1070508A (en) 1967-06-01

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