GB2601717A

GB2601717A - Towed buoys

Info

Publication number: GB2601717A
Application number: GB9509278.9A
Authority: GB
Inventors: Chalmers James; Gordon Jobling Peter
Original assignee: UK Secretary of State for Defence
Current assignee: UK Secretary of State for Defence
Priority date: 1994-05-09
Filing date: 1995-05-05
Publication date: 2022-06-08
Anticipated expiration: 2015-05-05
Also published as: GB2601717B

Abstract

A towed communication buoy for towing behind a submerged submarine comprises a forebody 11 with means for attaching a towing cable 10 and having a relatively high buoyancy which can be positive or negative. Pivoted to the forebody 11 is an afterbody 12 having a buoyancy low relative to the forebody 11. The forebody 11 may be spherical or cylindrical and the afterbody made near neutral buoyancy such that it aligns with the local water flow. The buoy is preferably made of high density syntactic foam and provided with a thin layer of GRP. The buoy houses communications aerials 14 and a spooling arrangement 15 for deployment of the aerials. An elevator 17 provides hydrodynamic lift to adjust the buoyancy of the buoy.

Description

Towed Buoys The invention relates to buoys suitable for towing behind ships and in particular, to comnifinications buoys for towing behind submerged submarines.

Current submarine towed communications are designed to achieve the required depth separation from the parent submarine by means of a combination of static buoyancy and dynamic lift. At slow speed, lack of dynamic lift and relatively low static buoyancy results in dangerously low cable tensions with the possibility of 'riding' turns on the storage winch, subsequent cable jamming and also the loss of buoy control. In general, performance at medium to fast speeds is satisfactory except that in high sea states the buoy's pitch equilibrium is disturbed by the surface motion. This results in variable lift and dynamic loading of the tow cable which in extreme conditions can lead to premature fatigue failures.

The object of the present invention is to provide a towed buoy which overcomes or reduces problems associated with existing towed buoys.

The invention provides: a towed buoy for towing behind a submerged submarine comprising: a forebody provided with means for attaching a towing cable and having a relatively high, positive or negative, buoyancy; and an afterbody pivotally connected to the forebody and having a relatively low, positive or negative, buoyancy.

Advantageously, the afterbody is streamlined and near neutral buoyancy such that it aligns with the local water flow without creating variable lift forces. By making the forebody positively buoyant the buoy can be used for towing equipment such as communications aerials near the sea surface. As the towing speed changes the forebody rotates to align with the tow cable. Alternatively, by making the forebody negatively buoyant, the buoy may be used for towing sensing equipment for example below the depth of the submarine. The forebody may advantageously be spherical or cylindrical and pivoted to the afterbody respectively about a diameter thereof or the cylindrical axis. In a positively buoyant arrangement the buoy may be constructed of high density syntactic foam to withstand pressure to full diving depths and provided with a thin coating of GRP to withstand handling forces.

For communications, the afterbody may house cross loop aerials and electronics for reception of VLF/LF and a spooling system for deployment from the buoy of a buoyant antenna wire for HF.

A pivotal elevator may be provided at the end of the afterbody remote from the forebody. The elevator may then be controlled to provide hydrodynamic lift to supplement the buoyancy of the forebody.

The invention will now be described by way of example only with reference to the accompanying drawing of which: Figure 1 is a schematic side elevation of a buoyant towed body; Figure 2 is a front elevation of the towed body; and Figure 3 is a plan view from the top of the towed body.

A buoyant body for towing behind a submarine is shown in Figures 1-3. A towing cable 10 is connected to a highly buoyant spherical forebody 11. The forebody 11 may be made of high density syntactic foam with a thin surface coating of GRP so as to be able to withstand large pressure depths and be resistant to handling forces. A streamlined afterbody 12 is pivotally attached to the forebody 11 about an axis 13 passing through the centre of the forebody. The afterbody 12 is arranged to be neutrally buoyant such that in use it aligns with the flow of water, pivoting relative to the forebody 11 as the towing speed, and in consequence the angle of the towing cable 10, changes.

The afterbody 12 houses communications aerials such that these aerials can be deployed close to the surface of the water while the towing submarine remains underwater. As shown the afterbody 12 may include a cross loop aerial assembly 14 for VLF/LF communications and a spool 15 for deploying a buoyant wire aerial 16 for HF communications.

Electrical connections from the antennae and associated electronics in the afterbody 12 are made through a flexible link cable to the forebody 11, and hence to the towing cable, to allow free movement of the forebody relative to the afterbody within a 90° arc for the zero to maximum towing speed positions. A limited automatic depth keeping system may be provided. As shown, an elevator 17 is provided at the rear of the afterbody. Adjustment of the angle of incidence of the elevator 17 to the flow of water is used to provide controlled hydrodynamic lift to supplement the buoyancy of the towed body.

In an alternative arrangement the spherical forebody may be replaced by a cylindrical body, the afterbody being pivoted about the cylindrical axis of the forebody. For communications, the forebody has a high positive buoyancy such that the buoy is towed above the submarine. In a further application of the invention the buoy may be arranged such that the forebody has a high negative buoyancy. The buoy may then be towed below the submarine and may house sensors for making measurements at depth.

Claims

Claims 1 A towed buoy for towing behind a submerged submarine comprising: a forebody provided with means for attaching a towing cable and having a relatively high, positive or negative, buoyancy; and an afterbody pivotally connected to the forebody and having a relatively low, positive or negative, buoyancy.
2 A towed buoy as claimed in claim 1 wherein the forebody is spherical and pivoted to the afterbody about a diameter thereof.
3 A towed buoy as claimed in claim 1 wherein the forebody is cylindrical and pivoted to the afterbody about the cylindrical axis thereof.
4 A towed buoy as claimed in any one preceding claim wherein the afterbody is streamlined and near neutral buoyancy such that it aligns with the local water flow without creating variable lift forces.
A towed buoy as claimed in any one of claims 1 to 3 wherein the forebody is negatively buoyant and so formed to contain equipment for towing below the depth of the submarine.
6 A towed buoy as claimed in any one of claims 1 to 3 wherein the forebody is positively buoyant and so formed to contain equipment for towing above the depth of the submarine.
7 A towed buoy as claimed in claim 6 wherein the buoy is constructed of high density syntactic foam to withstand pressure to full diving depths and provided with a thin coating of GRP to withstand handling forces.
8 A towed buoy as claimed in claim 6 or 7 wherein the afterbody houses crossloop aerials and electronics for reception of VLF/LF communications and a spooling system for deployment from the buoy of a buoyant antenna wire for Hf communications.
9 A towed buoy as claimed in any one preceding claim wherein a pivotal elevator is provided at the end of the afterbody remote from the forebody.A towed buoy as claimed in claim 9 wherein there is provided means to control the elevator to provide hydrodynamic lift to adjust the buoyancy of the forebody.