GB2060507A

GB2060507A - Inflatable Liferafts

Info

Publication number: GB2060507A
Application number: GB8033420A
Authority: GB
Original assignee: RFD Inflatables Ltd
Current assignee: RFD Inflatables Ltd
Priority date: 1979-10-18
Filing date: 1980-10-16
Publication date: 1981-05-07
Also published as: GB2060507B

Abstract

An inflatable liferaft comprising a pressurised air or gas inflation unit 17, 18, 19, elongate flexible support means 20 connected between a point of attachment on the liferaft and the inflation unit for supporting the inflation unit at a position remote from the point of attachment and carrying an air or gas flexible supply line or lines 21, 22 from the inflation unit to the liferaft, whereby during inflation of the liferaft the point of attachment has freedom to move relative to the inflation unit. A two raft pack is described in which a common inflation unit is provided. <IMAGE>

Description

SPECIFICATION Inflatable Liferafts The present invention relates to inflatable Iiferafts and is particularly, although not exclusively, concerned with an inflatable liferaft which is stowed in a deflated and folded condition in a container and which is inflated from pressurised air or gas inflation cylinders attached to the liferaft and packed with it within the containter.

It has been common practice to mount the inflation cylinders on the underside of the liferaft and so arrange the packing of the liferaft within the container that the inflation cylinders are lowermost. Provision is made for opening the cylinders for inflation of the liferaft either automatically upon entry of the container into the water or manually by pulling on a pull cord extending from the container. Pulling on the pull cord initiates inflation of the liferaft causing it to break out of the container. As it inflates fully the container fills with water and sinks away from the liferaft.

It has been proposed to provide for two 42 person liferafts to be stowed in a deflated condition in a single container so as to form an 84 person survival unit. The two liferafts are packed side by side in the container with their inflation cylinders lowermost and provision is made for opening the inflation cylinders simultaneously by operating a single pull cord extending from the container. It has, however, been found that with the containers mounted on the underside of the liferaft conditions are likely to arise in which the inflation cylinders get caught up and wedged against the wall of the container as the two liferafts inflate and push each other apart on the surface of the water.

It is an object of the present invention to provide an inflatable liferaft which does not suffer from the disadvantage referred to above when stowed as aforesaid as one of a pair in a single container.

According to the present invention, there is provided an inflatable liferaft comprising a pressurised air or gas inflation unit, and elongate flexible support means connected between a point of attachment on the liferaft and the inflation unit for supporting the inflation unit at a position remote from the point of attachment carrying an air or gas flexible supply line or lines from the inflation unit to the liferaft, whereby during inflation of the liferaft the point of attachment has freedom to move relative to the inflation unit.

Preferably, the inflation unit comprises one or more pressurised air or gas inflation cylinders stowed in a holder and the flexible support means comprises a flexible tube through which the air or gas supply line or lines pass and which is secured at one end to the holder and at the other end to the point of attachment on the liferaft at a strongpoint thereon.

One embodiment of the invention will now be described by way of example with reference to the accompanying drawings.

Fig. 1 is a persective vlew of an inflatable liferaft according to the invention, and Fig. 2 is a schematic plan view of a survival unit during inflation and comprising two liferafts as shown in Fig. 1.

Referring first to Fig. 1 of the drawings, the liferaft shown comprises two superposed endiess inflatable buoyancy tubes 11 and 12, a floor 13 which is secured at its periphery to the base of the lower buoyancy tube 12 and a canopy 14 secured at its periphery to the upper buoyancy tube 11 and supported by a canopy support structure formed by a pair of inflatable arched canopy support tubes, each of which has two leg portions extending upwardly and inwardly from spaced positions along the buoyancy tube 11 to the centre of the liferaft where they are Joined by a bridge portion which is juxtaposed to a bridge portion of the other arched tube, the leg portions of which extend upwardly and inwardly from spaced positions on the other side of the liferaft.

One leg portion 1 5 of one of the canopy support tubes is revealed in Fig. 1 through one of four openings 16 provided in the canopy 14. The openings 1 6 are formed in the canopy 14 at equiangularly spaced positions around the liferaft and each is closable by a closure sheet (not shown).

The interiors of the two buoyancy tubes 11 and 12 have no communication with each other and are arranged to be inflated separately. One of the arched canopy support tubes is arranged to be inflated from inflation air supplied to the buoyancy tube 11 while the other canopy support tube is arranged to be inflated by the lower buoyancy tube 12.

An inflation unit 10 for inflation of the buoyancy tubes 11 and 12 are their associated canopy support tubes comprises two pressurised nitrogen inflation cylinders 1 7 and 18 housed in a holder 19 secured to the liferaft by a flexible inextensible tube 20, one end of which is attached to the holder 1 9 and the other end of which is secured to a strong point on the lower buoyancy tube 12. High pressure small bore supply hoses 21 and 22 extend from the cylinder outlets through the tube 20 to aspirators 23 and 24 carried by the buoyancy tubes 11 and 12. The inflation cylinders 17 and 18 are arranged to be opened either automatically or manually by pulling on a pull cord (not shown).The pressurised nitrogen supplied to the hoses 21 and 22 is fed into the buoyancy tubes 11 and 12 via the aspirators 23 and 24 which supplement the nitrogen fed thereto by entraining ambient air.

The length of the tube 20 is such in relation to the length of the hoses 21 and 22 as to absorb any tensile loads which might otherwise be imposed on the hoses in use of the liferaft.

The liferaft shown in Fig. 1 has a service capacity of 42 persons with an outside diameter of 5.28 metres, an inside diameter of 4.46 metres and an overall height of 1.80 metres. For a liferaft of this capacity each inflation cylinder may contain air or nitrogen at 3000 p.s.i. (20.68 MPa).

It has been found advantageous to provide a survival unit in which two 42-persons liferafts as shown in Fig. 1 are coupled together to offer a total service capacity of 84 persons. The two liferafts together with their inflation units 10 are stowed in a deflated and folded condition in a cylindrical container formed by two semicylindrical half shells which are held together by straps which give way under loading imposed upon them by initial inflation of the Iiferafts in the container.

Referring now to Fig. two coupled liferafts 25 and 26, shown inflated in Fig. 2, are packed in a deflated and folded condition on top of their inflation units 10 in the lowermost half shell 28 of their container which is closed by fitting the other half shell (not shown) to the half shell 28 and securing them together by straps as hereinbefore described.

Actuation of the inflation cylinders 17 and 1 8 of the two inflation units 10 is obtained by pulling on a single pull cord (not shown) extending from the container and, in use, the container housing the two llferafts 25 and 26 is dropped into the water and the cord pulled hard. Nitrogen discharges from the cylinders 17 and 18 and via the aspirators into the buoyancy tubes 11 and 12 of the two liferafts causing them ta inflate. During the initial stages of inflation, the Iiferafts 25 and 26 expand within the container and break the straps holding the two half shells of the container together. The liferafts 25 and 26 then inflate out of the container and are held in coupled side-byside relation by a releasable attachment 27, as shown in Fig. 2.During inflation, the points of attachment of the tubes 20 to the two liferafts 25 and 26 are forced away from each other and from the container half shell 28. The inflation units 10, however, remain within the half shell 28 and by virtue of the length of the flexible hoses 21 and 22 and their support tubes 20 cause no obstruction to the inflation of the liferafts on the water. The inflation units remain in the half shell 28 until the latter fills with water and sinks.

The aspirators 23 and 24 are inoperative until they are above water level, whereupon they take in ambient air to boost the high pressure air or gas from the cylinders. In this way, rapid inflation is achieved in less than 30 seconds. After the inflation cylinders 17 and 18 have become discharged, the air intakes on the aspirators 23 and 24 automatically close and are locked in the closed position. The attachment 27 can, if desired, be released by a simple action of a survivor to allow separation of the two Iiferafts.

Claims

1. An inflatable liferaft comprising a pressurised air or gas inflation unit, and elongate flexible support means connected between a point of attachment on the liferaft and the inflation unit for supporting the inflation unit at a position remote from the point of attachment and carrying an air or gas flexible supply line or lines from the inflation unit to the liferaft, whereby during inflation of the liferaft the point of attachment has freedom to move relative to the inflation unit.

2. A liferaft according to claim 1, wherein the inflation unit comprises one or more pressurised air or gas inflation cylinders stowed in a holder and wherein the flexible support means comprises a flexible tube through which the air or gas supply line or lines pass and which is secured at one end to the holder and at the other end to the point of attachment on the liferaft at a strong point thereon.

3. A survival unit comprising a container and a liferaft according to claim 2, wherein the liferaft is housed in a deflated and folded condition in the container together with its inflation unit, and wherein the lengths of the flexible support tube and the air or gas supply line or lines passing therethrough are such as to permit inflation of the liferaft out of the container and into a fully inflated disposition without the need for withdrawal of the inflation unit from the container.

4. A survival unit according to claim 3, comprising a further liferaft housed in a deflated and folded condition in the container together with its inflation unit and coupled to the other liferaft at a coupling point on its periphery and a coupling point on the periphery of the other liferaft, whereby the two liferafts upon inflation out of the container take up fully inflated dispositions on the water in which they are held together at their coupling points and wherein the lengths of the flexible support tubes and the air or gas supply line or lines and their points of attachment to the liferafts are such that the two liferafts can take up their fully inflated dispositions on the water without the need for withdrawal of the inflation units from the container.

5. A survival unit according to claim 4, wherein the container is of cylindrical configuration and is made from two semi-cylindrical half shells held together by straps which break under load applied thereto by inflation of the liferafts within the container.

6. A survival unit according to claim 5 wherein the inflation units are so arranged as to be lowermost in the container and remain in the lowermost half shell of the container during deployment in water and during inflation of the two liferafts out of the container.

7. A survival unit according to claim 6, wherein the inflation units are free to withdraw from the container half shell when the latter fills with water and sinks.

8. A unit according to any of claims 4 to 7, wherein the liferafts are of circular configuration and wherein the points of attachment of the flexible support tubes to the liferafts are spaced from the coupling points of the liferafts.

9. A survival unit substantially as hereinbefore described with reference to the accompanying drawings.