US3585956A

US3585956A - Stabilizers

Info

Publication number: US3585956A
Application number: US829156A
Authority: US
Inventors: Roger Edward Gwynn; Michael John Turnham; Alexander Arthur Tann
Original assignee: MUIRHEAD Ltd
Current assignee: MUIRHEAD Ltd
Priority date: 1968-05-29
Filing date: 1969-05-23
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22
Also published as: DE1927377A1; GB1226622A; NL6908183A; FR2009590A1

Abstract

A marine fin stabilizer for use with a small ship is provided with a plate for attachment to the outside hull of the ship and which carries the fin-tilting mechanism. Fluid pressure conduits extend from the mechanism through the plate to control equipment mounted inside the hull of the ship. The invention avoids the requirement for a fin shaft gland having to be made in the ship''s hull and for the fin-tilting mechanism to be accommodated inside the hull.

Description

United States Patent [72] Inventors Rogerlidward Gwynn [50] Field 114/126 London;

ReferencesCited UNITED STATES PATENTS 1/1961 Fol] 3,172,389 3/1965 Michael John Turnham, London; Alexander-Arthur Tann, West Wickhnm, all of, England [21 1 Appl. No. 829,156

[22] Filed May 23, 1969 4s Patented June 22, 1971 W -YE 73 1 Assignee Muir-head Limited army-Holman & Stem Beckcnhnm, Kent, England [32] Priority May 29, 1968 1 W ABSTRACT: A marine fin stabilizer for use with a small ship is 25,693/68 provided with a plate for attachment to the outside hull of the ship and which carries the fin-tilting mechanism. Fluid pressure conduits extend from the mechanism through the plate to control equipment mounted inside the hull of the ship. The invention avoids the requirement for a fin shaft gland having to be made in the ships hull and for the tin-tilting mechanism to be accommodated inside the hull.

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PATENTEU JUH22 I971 SHEET 1 BF 3 INVENTORS'.

ROGER EDWARD GWYNN MICHAEL JOHN TURNHAM ALEXANDER ARTHUR TANN PATENTEU JUN22 l9?! SHEET 2 OF 3 INVENTORSI ROGER EDWARD GWYNN MICHAEL JOHN TURNHAM ALEXANDER ARTHUR TANN PATENT EU JUN22 I971 SHEET 3 UF 3 INVENTORSI ROGER EDWARD GWYNN MICHAEL JOHN TURNHAM ALEXANDER ARTHUR TANN STABILIZERS BACKGROUND OF THE INVENTION Conventional stabilizers use a fin integral with a rotatable shaft which passes through a watertight gland in the ship's hull. The inner end of the shaft is connected to a tin-tilting mechanism.

The use of fin stabilizers in relatively small vessels such as yachts, fishing vessels and mine-sweepers ranging up to 1500 tons is not normally considered worthwhile as the cost of the installation in relation to the advantage gained is relatively high. Moreover, the compartments occupied by the tin-tilting mechanism inside the hull represent a loss of space.

A further disadvantage of the conventional arrangement of stablilizer is that it does not lend itself to fitting economically to a ship already constructed. It will be appreciated that extensive major modification to the ship's hull is normally necessary if it is to be fitted with a fin stabilizer and such work can normally only be undertaken in relatively large dockyards at a relatively high price.

An object of this invention is the provision of a relatively cheap and relatively easily fitted fin stabilizer assembly.

SUMMARY OF THE INVENTION In accordance with the broadest aspect of this invention a stabilizer fin assembly for fitting to a ships hull comprises a plate for external attachment to the ship's hull, a shaft extending transversely away from one face of the plate to which it is rigidly fixed, a fin arranged to be rotatably mounted on the shaft by means of a water-lubricated bearing, and a controllable fin-tilting mechanism attached to the plate so that it is carried outside the hull with the mechanism being operable to control the angle of tilt of the fin on the shaft.

The invention has the advantage that it is able to provide a relatively cheaply constructed fin assembly capable of being fixed externally to a ship's hull without the provision of an expensive gland having to be constructed in the ship's hull to accommodate a fin-tilting shaft, and without the requirement for bulky fin-tilting mechanisms to be mounted within the ships hull. The assembly can be fitted to a relatively small vessel, such as a yacht, at a relatively low price and without major structural alteration to the hull of the vessel.

In the preferred arrangement, the shaft comprises a steel rod welded to one face of the plate and cemented inside a cylindrical tube of a material such as that known under the Registered Trade Mark Tufnol" which provides one surface of the water-lubricated bearing. The fin may also be provided with an integral Tufnol" sleeve which is a sliding fit over the shaft tube so that a water-lubricated bearing is provided there.

The outer end of the shaft tube beyond the end of the metal rod may be plugged by a spigot which is cemented to the rod with a suitable adhesive, such as that known under the Registered Trade Mark Araldite" which may also be used to cement the Tufnol" tube to the rod. The end of the spigot may be externally threaded in order to receive a nut for holding the fin in place on the shaft.

The rotation of the fin about the shafi axis is suitably carried out by a member encircling the shaft and arcuately movable by the tilting mechanism. The movement of the member is conveniently imparted to the adjacent and face of the tin by a pin and socket or other form of readily disconnectable attachment.

The fin-tilting mechanism suitably includes a double-ended piston mounted on the plate within a mask which protects the fin-tilting mechanism from impact with floating objects.

The working fluid applied to the cylinder is preferably pneumatic rather than hydraulic and it is transmitted to the fin assembly by way of tubing extending to a suitable control system which may be of the form described in our copending application Ser. No. 827,278 filed May 23, 1969, hereby inserted by way of reference. The pneumatic path provided by the tubing preferably passes through the ships hull beneath the plate by way of a fixture. The tubing may, if required, be cleated to the outside of the ship's hull and arranged to extend upwardly from the plate to a position above the waterline where it can be led inboard to the control unit.

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view, partly in section, of a fin stabilizer assembly;

FIG. 2 is a vertical section taken on the line and in the direction indicated by the arrows ll-II in FIG. 1; and,

FIG. 3 is a view of the fin-tilting mechanism shown in FIG. 1 and taken in the direction of the arrow A, with the fin and mask having been removed.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 3 the fin stabilizer assembly comprises a generally flat plate 1 having bolt holes 2 formed therein and made of mild steel treated so as to be resistant to sea water corrosion. Welded to the plate I is one end of a cylindrical steel rod 3 (FIG. 2) whose other end is cemented into the bore of a tube 4 made of material such as that known under the Registered Trade Mark Tufnol." Cemented into the outer end of the tube 4 is a nylon plug 5 externally threaded at 6 to receive a lock nut 7. The nut 7 holds in place on the outside of the tube 4 a stabilizing fin 8.

Welded to the plate 1 about the rod 3 is a steel strengthening collar 10. This collar abuts the inner end of the tube 4 and provides a cylindrical surface which is cemented into the bore of a Tufnol" ring 11. The outer surface of the ring 11 and the adjacent portion of the tube 4 provide a water-lubricated bearing for a partially rotatable cross-head 12 constructed as a one-piece moulding of Tufnol." A flange 14 on the collar 10 holds the cross-head 12 away from the surface of the plate 1. A pair of corrosion-resistant drive pins 15 are cemented into respective holes in the crosshead 14 so that their outer ends 16 locate in cups I7 which are integrally formed in the adjacent end face of the fin 8.

The crosshead 12 is of generally rectangular form as shown in FIG. 3 and is provided with slotlike recesses 46 across each of which extends a rotatable pin 47 to which is clamped by a bolt 18 an endpiece 20. Each endpiece has screwed therein one threaded end 21 of a piston rod 22 which extends to a double-ended piston reciprocable inside a cylinder 23.

The two piston and cylinder units provide with the crosshead 12 a fin-tilting mechanism. Working chambers in opposite ends of each of the cylinders 23 are connected by connectors 24 to flexible nylon piping 25 so arranged that the admission of pressure fluid through one of the two connectors 24 is accompanied by the admission of pressure fluid to the second connector 24' of the other cylinder 23.

Further nylon tubing

26 and 27 extends from connectors 24 of respective cylinders to fixtures 28 provided in the plate 1 and from which skin fittings project through the hull of the ship. Skin fittings are well known in the marine art for conveying pressure fluid through a ship's hull and they are therefore not shown. The inner ends of the skin fittings are connected by further piping inside the ship's hull to a suitably positioned control unit for adjusting air pressure admitted by way of the tubing to the cylinders 23 of the fin-tilting mechanisms. The control unit is preferably constructed as described in our above-mentioned copending Application.

The cylinders 23 have end lugs 30 rotatably mounted on pivot pins 31 welded to the plate 1. A pair of

pillars

32, 32

also welded to the plate l as shown in FIG. 1 have threaded ends onto which are screwed nuts 33 which hold in place a fiberglass molded mask 1% covering the fin tilting mechanism. The pillar 32 has mounted thereon a rubber ring 36 providing a buffer to limit resiliently rotary movement of the crosshead 12 to an angle of thirty degrees from the position shown in FIG. 3.

The construction of the fin will now be described.

The fin 8 is of symmetrical aerofoil cross section and its leading edge tapers slightly rearwardly towards its outside face.

Referring to FIG. 1, the fin is provided with a skeleton frame formed by a pair of

steel ribs

40, 41 disposed, respectively, adjacent the inner and outer ends of the fin and held in place by a pair of tiebars 42, 453 disposed towards the leading and trailing edges of the fin. A sleeve 44 made of the aforementioned Tufnol" has an internal diameter slightly larger than the external diameter of the tube 4 of the shaft which extends through .the thickest part of the tin 8 between the

ribs

40, 41. The frame and sleeve are fitted into a premolded fiberglass sheath providing the outside surface of the fin and the cavity of the fin is then filled with foamed polyurethane which is solidified in situ to provide a rigid and light filling to the sheath. Molded in situ in the polyurethane are the two cups 17 which receive the ends 16 of the pins 15 with a close fit.

The outer end face of the fin is provided with a counterbored recess 51 coaxially arranged with respect to the sleeve 44 and disposed outwardly of the rib 41 as shown in FIG. 1. The nut 7 which locks the fin to the shaft is largely accommodated within the recess 51. A screw 52 clamps the nut 7 in position as shown in FIG. 2. y

The above described assembly is duplicated on both sides of the ship and may be comparatively cheaply fabricated as well as being relatively easy to assemble and transport. Moreover it is relatively light.

To fit the fin assembly to the hull of the ship the plate 1 is bolted to the hull at the position required and the skin fittings are made at appropriate positions for connection through the plate 1 to the

tubing

26 and 27. The

tubing

26, 27 is then connected and the protective mask 3 is bolted to the pillars 32. Finally the fin is threaded onto the shaft which projects from the mask 34 and the protruding ends 116 of the pins 15 are located within the cups 117 of the fin.

The nut 7 is finally screwed onto the plug and the bolt 52 inserted to clamp it in position.

To operate the fin assembly compressed air is admitted selectively to the

piping

26, 27 while the other piping is simultaneously connected to atmosphere. The two piston and cylinder units are therefore operated in unison in respectively opposite directions to rotate the crosshead l2 and thus, by way of the pins 15, the fin We claim:

11. A marine stabilizer fin assembly comprising a ships hull, a plate externally attached to the ship's hull, a shaft extending transversely away from one face of the plate to which it is rigidly attached, a fin rotatably mounted on said shaft, a water-lubricated bearing supporting said fin on said shaft, a

fin-tilting mechanism attached to the outside of the plate, said mechanism comprising a member rotatable about said shaft, a second water-lubricated bearing between said member and said shaft, a fluid pressure operated arrangement connected between said member and said plate and expandable to rotate said member about said shaft, and quick-release connections between said member and said fin, and means extending from said mechanism to a tilt control unit mounted inside the ship.

2. The assembly as set forth in claim 1, in which said arrangement comprises two piston and cylinder units connected at one pair of respective ends to positions on said member on opposite sides of said shaft and at the other pair of respective ends to said plate, and said quick-release connections comprise pin and socket elements attached respectively to said member and to said fin.

3. A stabilizer fin assembly comprising a plate attached to a ships hull beneath the waterline, a steel rod welded to said plate, a tube of water-lubricated material cemented around a part of said rod, a plug cemented into the outer end of said 5 tube, a threaded end-portion to said plug, a fin having a bore threaded onto said tube, a lining of water-lubricated material to said bore, a recess in the outer end of said bore, a nut located in said recess and screwed onto said threaded end-portion of said plug, a mask fixed to said plate and defining an aperture around said shaft, a fin-tilting mechanism mounted within said mask, control connections extending to said mechanism from said plate, and means converting movement of said mechanism into tilting movement of said fin about said shaft.

4. The assembly as set forth in claim 3, in which said means and mechanism include a member threaded onto said shaft and located inside said mask, a water-lubricated bearing formed between said member and said shaft, dowel pins fixed in said member and 5 protruding towards said fin, cups formed in said fin and receiving end-portions of said dowel pins, fluidpressure expansion means connecting said member to said plate, and piping providing said connections between said plate and said expansion means of said fin-tilting mechanism.

5. The assembly as set forth in claim 4, in which said fluidpressure expansion means comprise two double-endedpiston and cylinder units extending to pivotal connections on said member at opposite sides of said shaft.

6. The assembly as set forth in claim 3, in which the fin is of molded nylon.

7. The assembly as set forth in claim 3, in which the tin comprises a fiberglass sheath containing a solidified filling of polyurethane, a metal frame embedded in said solidified filling, a tube of water-lubricated material embedded in said 5 filling and providing with said shaft a water-lubricated bearing, and parts of spigot-and-socket connections connecting said fin to said tilting mechanism.

8. The assembly as set forth in claim 3 in which fixtures passing through said plate are connected by flexible piping to said fin-tilting mechanism whereby tilting of said fin is determined by the fluid pressure selectively applied to said piping from a control unit mounted within the ship's hull and connected by further piping to said fixtures.

Claims

1. A marine stabilizer fin assembly comprising a ship''s hull, a plate externally attached to the ship''s hull, a shaft extending transversely away from one face of the plate to which it is rigidly attached, a fin rotatably mounted on said shaft, a waterlubricated bearing supporting said fin on said shaft, a fintilting mechanism attached to the outside of the plate, said mechanism comprising a member rotatable about said shaft, a second water-lubricated bearing between said member and said shaft, a fluid pressure operated arrangement connected between said member and said plate and expandable to rotate said member about said shaft, and quick-release connections between said member and said fin, and means extending from said mechanism to a tilt control unit mounted inside the ship.

3. A stabilizer fin assembly comprising a plate attached to a ship''s hull beneath the waterline, a steel rod welded to said plate, a tube of water-lubricated material cemented around a part of said rod, a plug cemented into the outer end of said 5 tube, a threaded end-portion to said plug, a fin having a bore threaded onto said tube, a lining of water-lubricated material to said bore, a recess in the outer end of said bore, a nut located in said recess and screwed onto said threaded end-portion of said plug, a mask fixed to said plate and defining an aperture around said shaft, a fin-tilting mechanism mounted within said mask, control connections extending to said mechanism from said plate, and means converting movement of said mechanism into tilting movement of said fin about said shaft.

4. The assembly as set forth in claim 3, in which said means and mechanism include a member threaded onto said shaft and located inside said mask, a water-lubricated bearing formed between said member and said shaft, dowel pins fixed in said member and 5 protruding towards said fin, cups formed in said fin and receiving end-portions of said dowel pins, fluid-pressure expansion means connecting said member to said plate, and piping providing said connections between said plate and said expansion means of said fin-tilting mechanism.

5. The assembly as set forth in claim 4, in which said fluid-pressure expansion means comprise two double-ended piston and cylinder units extending to pivotal connections on said member at opposite sides of said shaft.

6. The assembly as set forth in claim 3, in which the fin is of molded nylon.

7. The assembly as set forth in claim 3, in which the fin comprises a fiberglass sheath containing a solidified filling of polyurethane, a metal frame embedded in said solidified filling, a tube of water-lubricated material embedded in said 5 filling and providing with said shaft a water-lubricated bearing, and parts of spigot-and-socket connections connecting said fin to said tilting mechanism.

8. The assembly as set forth in claim 3 in which fixtures passing through said plate are connected by flexible piping to said fin-tilting mechanism whereby tilting of said fin is determined by the fluid pressure selectively applied to said piping from a control unit mounted within the ship''s hull and connected by further piping to said fixtures.