GB2339728A

GB2339728A - Life belt deployment system

Info

Publication number: GB2339728A
Application number: GB9811806A
Authority: GB
Inventors: Allan Mason
Original assignee: GLOBAL MARINE SAFETY Ltd
Current assignee: GLOBAL MARINE SAFETY Ltd
Priority date: 1998-06-02
Filing date: 1998-06-02
Publication date: 2000-02-09
Also published as: GB9811806D0

Description

2339728 IMPROVEMENTS IN MARINE RESCUE AND SAFETY APPARATUS This invention

is concerned with marine rescue and safety apparatus, and in particular with a release mechanism f or a flotation device such as a lifebelt or a liferaft.

While many improvements have been made in recent years to the general question of the safety of sailors the sea remains an extremely dangerous environment. one obvious danger is that of a man falling or being swept overboard without a buoyancy aid such as a lifejacket or lifebelt making drowning likely. Even if the man is wearing a buoyancy aid there remain the dangers of exposure which effectively put a limit on the time in which a rescue must be effected. This limit can be measured in minutes in many circumstances and it can be difficult at night or in stormy weather to turn a vessel around and locate let alone rescue a man overboard within the time limit.

It is an object of the present invention to provide marine rescue and safety apparatus that obviates or mitigates these problems.

The present invention is a release mechanism for a f lotation device, the mechanism comprising a launcher, a drogue located at least partially within the launcher for attachment to a flotation device outside the launcher, means for ejecting the drogue from the launcher, and means for securing the drogue in the launcher prior to ejection.

The means for ejecting the drogue may comprise a spring loaded piston.

Preferably the means for securing the drogue in the launcher comprises a latch mechanism having a latch engaging the drogue prior to ejection.

The latch may also engage the piston whereby upon activation of the latch mechanism the latch is withdrawn to enable the piston to eject the drogue.

The drogue preferably comprises a ballast weight and a collapsible canopy which in the water expands to act as a sea anchor.

The present invention is also marine rescue and safety apparatus comprising a controller having at least one input for receiving an indication of a man overboard and generating an output signal in response to the input indication, means for triggering an indication of the position of the man overboard to facilitate the return of the vessel to that position, and a release mechanism as claimed in any of the last six preceding paragraphs, the release mechanism being responsive to the output signal.

The controller may have a plurality of inputs, the or each input being linked with a signal generator.

The signal generator may be a pushbutton, a radio alarm or a chemical activator.

The flotation device is preferably a lifebelt or liferaft.

The navigational aid is preferably a global positioning system or an autopilot.

The controller may output one or more additional output signals to trigger one or more alarm systems.

The alarm systems may include an audible alarm, a search and rescue transponder or an electronic position indicating radio beacon.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Fig.1 is a perspective view of the stern of a yacht; Fig.2 is a block diagram of marine safety apparatus according to the present invention; Figs.3A and 3B are sectional elevations of an ejector according to the present invention; and Fig.4 diagrammatically illustrates the deployment of a drogue used in the present invention.

Referring now to Fig.2 of the drawings, marine rescue and safety apparatus has a controller 10 having a number of inputs, in this embodiment three, 12 14 and 16. The controller 10 is located on a vessel in a central location such as a bridge or wheelhouse and the input 12 is connected to a simple man overboard (MOB) pushbutton which when depressed generates an input signal to the controller. The input 14 is responsive to a radio signal generated automatically or manually by a small transmitter worn by the man overboard, and the input 16 responds to a radio signal generated in response to a chemical activator reacting to the presence of sea water. Any other signal generator, including further MOB pushbuttons, could be used instead. The further MOB pushbuttons would of course be located at different locations around the vessel. In Fig.1 is shown the stern of a yacht in which two MOB pushbuttons are located one at each side of the cockpit.

It is preferred to reserve one input to the controller 10 f or connection to a TEST pushbutton which when depressed in conjunction with a MOB pushbutton 15 results in an indication of the functionality of the MOB pushbutton.

When the controller 10 receives an input signal at an input it provides output signals on the output lines 17, 18 and 20. The signal on the line 18 is input to the release mechanism 22 of a flotation device. The signal 20 is passed to a navigational aid 24 and the signal 17 is passed to an audible alarm 26 and to an ejector mechanism 28 for a position marker.

The preferred flotation device is a liferaft or lifebelt 30 as shown in Fig.l. The navigational aid 24 is a global positioning system or autopilot which, on receiving the input from the line 20, notes the precise position thus assisting the return of the vessel to the point at which the man went overboard.

The audible alarm 26 alerts members of the crew to the situation while the ejector mechanism 28 ejects, or at least releases a position marker such as a Search and Rescue Transponder (SART) or an Electronic Position Indicating Radio Beacon (EPIRB). The position marker complements the navigational aid 24 as the man overboard will in time, under the influence of wind and tide, move further and further from the point recorded in the navigational aid rendering the position recorded by the aid 24 less and less accurate whereas the position marker is free floating and will tend to move with the man in the water and indicate his current position more accurately for longer.

The apparatus described operates to provide the man in the water with buoyancy to avoid the immediate danger of drowning and protection against exposure if a liferaft if released, and the crew of the vessel is provided with at least one method of establishing the position in the water of the man overboard which greatly facilitates the speedy return of the vessel to rescue the man.

It is also advantageous to arrange that, when testing the MOB pushbuttons using the test button, an output signal is provided on the lines 17 and 20 that is sufficient to trigger the systems 22 and 24 and the alarm 26 but not the ejector 28, thus allowing the system to be used for training purposes without releasing the flotation device.

The release mechanism 22 for releasing the buoyancy aid according to the present invention is illustrated in Figs.3A and 3B and consists of a launch tube 40, a drogue 42, a latch mechanism 44 for securing the drogue 42 in the tube 40, and a spring loaded piston 46 for ejecting the drogue from the tube 40.

The launch tube 40 is open at its bottom end but has a removable end cover 50 closing its top end; a watertight seal 52 is located between the cover 50 and the tube 40. The launch tube 40 has two internal flanges 52 and 54, and on its side is mounted a watertight housing 56 containing the latch mechanism 44.

The drogue consists of a central rod 60, a ballast weight 62 at the bottom of the rod 40, a collapsible canopy 64 similar to an inverted umbrella attached to the rod 60 immediately above the weight 62, a collar 66 on the rod 60 immediately above the top of the canopy 64, and a latch recess 68 at the top of the rod. A line such as a rope 70 is attached to the free upper end of the canopy 64 and is attached to a flotation device such as a lifebelt 30 (Fig.1) at the stern of the boat.

The latch mechanism 44 includes a latch 72, which projects into the launch tube and is movable longitudinally between an advanced position shown in Fig.3A to which it is biassed, in this embodiment, by a spring (not illustrated) and a retracted position as shown in Fig.3B. Movement of the latch 72 to the retracted position is achieved by any convenient means, in this embodiment by a solenoid energised through the line 18 by the controller 10.

The piston has a head 80 at its lower end and an upwardly extending body 82, the diameter of the head 80 being the same as the internal diameter of the tube 40. The head 80 is located between the two internal f langes 52 and 54. The body 80 has a smaller diameter, and an axial passage 84 extends through the head 80 and body 82 and communicates with a transverse passage 88. A coil spring 90 is located around the body and is seated between the upper flange 52 and the head 80 of the piston to bias the piston downwardly in the tube.

A handle 94, trapped in the space between the upper internal flange 52 and the cover 50, is attached by a flexible member, in this embodiment a chain 96, to the top of the body of the piston, the length of the chain being such that it remains slack when the piston abuts the lower flange 54 as shown in Fig.3A.

To put the release mechanism 22 into its standby condition, illustrated in Fig.3A, the cover 50 is removed and the handle 94 is used to draw the piston 46 up in the launch tube until the latch 72, under the influence of its bias spring, moves into the transverse passage 88 to hold the piston up against the downward force of the now compressed coil spring 90.

A drogue 42, with its canopy collapsed, is inserted into the bottom of the launch tube to engage its rod 60 in the axial passage 84, and is then moved up in the tube until the latch engages the latch recess 68. The mechanism is now as shown in Fig.3A and is ready for use.

Upon receipt of a signal from the controller 10 on the line 18, the latch solenoid is energised to withdraw the latch to the position shown in Fig. 3b where it is clear of both the rod 60 and the passage 88 in the body of the piston. The coil spring 90 forces down the piston and, as the piston head engages the collar 66 on the rod 60, the drogue also. When the piston reaches the bottom of its stroke as the piston head engages the lower flange 54, the position shown in Fig.3B, the drogue continues alone and is ejected from the bottom of the launch tube with a velocity of about 22 metres/sec.

In Fig.4 are shown the four stages in the deployment of the drogue. At stage A the drogue has been ejected but has not yet hit the water. At stage B, approximately 0.07 seconds after energisation of the solenoid, the drogue is in the water and is beginning to sink under the influence of the ballast weight 62 as the vessel moves away from the point at which the drogue was launched. Almost immediately, however, the rope 70 connecting the canopy to the lifebelt on the boat is drawn tight (stage C) and as the drogue begins to be dragged through the water the canopy expands as a sea anchor (stage D) and the resulting tension in the rope drags the flotation device from the vessel into the water close to the man overboard.

It should also be noted that whereas a free floating lifebelt or the like tends to be blown away from a man in the water, this tendency is minimised with the equipment of the present invention because the drogue continues to function as a sea anchor after the lifebelt is in the water.

In a modification of the embodiment described the piston is forced down the launch tube by a compressed gas rather than by a spring.

A modified drogue is made rigid, preferably of metal, and the canopy is replaced by a propeller, which is preferably shrouded, and a swivel joint for connection to the line 70. With this drogue the propeller is preferably larger than the diameter of the launch tube and abuts the bottom of the launch tube.

Claims

I A release mechanism for a. flotation device, the mechanism comprising a launcher, a drogue located at least partially within the launcher for attachment to a flotation device outside the launcher, means for ejecting the drogue from the launcher, and means for securing the drogue in the launcher prior to ejection.
2. A release mechanism as claimed in claim 1, in which the means for ejecting the drogue comprises a spring loaded piston.
3. A release mechanism as claimed in claim 1 or claim 2, in which the means for securing the drogue in the launcher comprises a latch mechanism having a latch engaging the drogue prior to ejection.
4. A release mechanism as claimed in claim 3 when dependent on claim 2, in which the latch also engages the piston whereby upon activation of the latch mechanism the latch is withdrawn to enable the piston to eject the drogue.
5. A release mechanism as claimed in any preceding claim, in which the drogue preferably comprises a ballast weight and a collapsible canopy which in the water expands to act as a sea anchor.
6. A release mechanism as claimed in any of claims 1 to 4, in which the drogue comprises a propeller and a swivel joint for connection to a line.
7. A release mechanism for a flotation device substantially as hereinbef ore described with ref erence to and as shown in the accompanying drawings.
8. Marine rescue and safety apparatus comprising a controller having at least one input for receiving an indication of a man overboard and generating an output signal in response to the input indication, and responsive to the output signal for triggering an indication of the position of the man overboard to facilitate the return of the vessel to that position, and a release mechanism as claimed in any preceding claim, the release mechanism being responsive to the output signal.
9. Apparatus as claimed in claim 8, in which the controller has a plurality of inputs, the or each input being linked with a signal generator.
10. Apparatus as claimed in claim 8 or claim 9, in which the signal generator is a pushbutton, a radio alarm or a chemical activator.
11. Apparatus as claimed in any of claims 7 to 10, in which the flotation device is a lifebelt or liferaft.
12. Apparatus as claimed in any of claims 7 to 11, in which a navigational aid is responsive to the output signal to indicate the position of the man overboard.
13. Apparatus as claimed in claim 12, in which the navigational aid is a global positioning system or an autopilot.
14. Apparatus as claimed in any of claims 7 to 13, in which the controller outputs one or more additional output signals to trigger one or more alarm systems.
15. Apparatus as claimed in claim 14, in which the alarm systems include an audible alarm, a search and rescue transponder or an electronic position indicating radio beacon.
16. Marine rescue and safety apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawing.