GB2066193A - An inflatable life-raft - Google Patents

Abstract

Inflatable life-rafts are liable to overturn during inflation or when only lightly loaded and it is known to provide these lift-rafts with discrete stabilisation pockets secured to the floor of the life-raft. However, the opening and filling of known stabilisation pockets has proved unreliable and the present invention serves to provide a life-raft having an improved stabilisation pocket. The life-raft comprises an inflatable peripheral tube (8) having a floor (6) secured thereto. A collapsable pocket (10) is located beneath the floor of the raft and co-extensive therewith. Water inlets (22) are provided in the periphery of the pocket. Preferably the pocket is made of a light-weight fabric material. <IMAGE>

Description

SPECIFICATION An inflatable life-raft This invention relates to an inflatable life-raft and in particular to an inflatable life-raft having a stabilising pocket.

Inflatable life-rafts are light weight in relation to their size with the consequence that they may be easily overturned by the winds frequency experienced at sea. Life-rafts are most likely to overturn during or shortly after inflation when they are only lightly loaded. To improve the stability of inflatable life-rafts it is known to provide the underside of a raft with discrete stabilisation pockets which fill with water and which counteract any force attempting to lift and overturn the life-raft.

A known inflatable life-raft having a base surrounded by an inflatable peripheral tube has three separate stabilisation pockets attached to the underside of the raft adjacent to the peripheral tube. Each pocket is constructed of heavy rubber impregnated fabric and is rectangular in shape. An opening is provided in the bottom of each pocket to allow water to enter the pocket. The opening also serves as a drain.

Because the life-raft is tightly packed for the greater period of its life, when the life-raft is inflated the pockets tend to remain in a compressed state and the intended water ballast only slowly enters the pockets.

In some instances only partial filling occurs or in extreme cases no filling occurs with the consequence that the maximum stabilishing effect is not achieved. In this situation the raft may, especially if lightly laden, be constantly at risk of overturning.

The stabilisation pockets are subjected to the movement of the sea and this movement may give rise to a pumping action in which the water is pumped into and out of the stabilisation pockets.

To induce the water to enter the stabilisation pockets more quickly it has been proposed to insert an open celi foam into the pockets. The foam can be compressed for storage purposes and, in use, water will fill the cells of the foam. However, this arrangement is not entirely successful because even in the compressed condition the foam is bulky, especially when used in large pockets to achieve maximum stability.

An object of the invention is to provide a stabilising pocket for an inflatable life-raft, which will fill more quickly and provide improved stability compared with known stabilisation pockets.

According to the present invention there is provided an inflatable life-raft comprising a base including a floor secured to and surrounded by an inflatable peripheral tube, a collapsable pocket located beneath and co-extensive with the base of the raft, and water inlets or openings adjacent to the inflatable peripheral tube to admit water to the pocket to stabilise the raft.

Preferably the life-raft further includes mechanical opening means arranged between the floor and the pocket wall to facilitate unfolding of the pocket.

Conveniently the mechanical opening means is a semi-rigid tube attached to the floor by a moulded rubber base piece. An advantage of a life-raft housing this preferred mechanical opening is that the pumping action which is generated by sea movement and which affects the filling of the stabilisation pockets may be reduced.

The wall of the pocket may conveniently be secured at spaced intervals around its circumference to the peripheral tube. The openings, to admit water to the pocket, being formed between the circumferential edge of the pocket wall and the base between the respective securing points. The pocket wall is conveniently constructed of light weight textile fabric, for example of nylon.

In an alternative embodiment the mechanical opening means is one or more ballast weights attached to the wall of the pocket. Conveniently further water inlets are provided in a central region of the pocket wall.

In a further alternative embodiment a tubular sleeve is provided between the floor of the life-raft and the pocket wall, whereby a rod, acting as the mechanical opening means, may be inserted into the tubular sleeve to unfold the pocket.

The present invention will now be described further by way of example only with reference to the accompanying drawings, in which: Figure 1 is an end view of one embodiment of the invention as applied to a pentagonal inflatable life-raft; and Figures 2 to 4 show diagrammatically how the pocket is opened during the inflation of the life-raft.

Figure 1 illustrates, in its inflated condition, an inflatable life-raft constructed from a rubber impre gnatedtextile; the rubberised coating provides the required gas retention and water resistance. The particular life-raft illustrated is provided with a canopy which encloses the accomodation provided by the raft.

The life-raft generally indicated by the reference 2 has a base 4 which includes a floor 6 secured to and surrounded by an inflatable peripheral tube 8. In the illustrated embodiment of Figure 1 the peripheral tube has a pentagonal configuration, although the invention may be applied to other shaped life-rafts.

In accordance with the invention a pocket 10 is located beneath the base of the raft and is coextensive therewith. That is, it extends across the entire under surface of the base of the raft and shares the same peripheral boundary.

In the embodiment illustrated the pocket is defined between the base of the raft and a pocket wall 12.

The pocket wall is constructed from five sections of material 14 (only three of which are visibie in Figure 1) which are stitched together along radial seams 16 and the pocket wall is secured to the peripheral tube at location points 18 spaced at intervals around the circumference of the peripheral tube. The pocket wall is stitched to patches at the location points and these patches are glued to the peripheral tube.

Whilst this is the preferred form of attachement any other convenient method of attaching the pocket wall to the raft may be used. In an alternative construction the pocket wall may be a single piece of material appropriately shaped.

The pocket wall is only secured to the life-raft along its peripheral edge 20 at the location points and the remaining free edge portions of the pocket wall act as water inlet vents or openings 22. Thus water can pass between the edge of the pocket wall and the peripheral tube to be admitted into the pocket. In the illustrated arrangement the pocket wall is secured to the life-raft at ten location points 18, thus ten water inlet vents 22 are provided.

The pocket wall is preferably constructed from light weight textile material, for example a typical parachute fabric of light weight nylon. The fabric may not be treated with a water resistant coating.

The life-raft of necessity, spends most of its life tightly folded in its canister, but it is essential that it unfolds and inflates whenever it may be required. It has been mentioned that inflatable life-rafts are light in relation to their size and they may overturn during inflation and thus stabilisation pockets have been used in the past. The stabilisation pocket of the present invention has the advantage that it is constructed from a lightweight fabric and thus it is less likely to remain creased when the life-raft is inflated. Further water inlets 25 may be provided in the central region of the pocket wall to aliow water to be admitted more quickly if required in a specific design. These are shown dotted in Figure 1. These would also provide for drainage of pocket after use, if the raft is to be re-packed.

The water contained in the stabilisation pockets is intended to counteract the lifting forces applied to the life-raft. Thus by providing a stabilising pocket which is co-extensive with the base of the raft, rather than merely discrete pockets, a much greater stabilisation effect may be achieved. The streamline shape of the pocket,which has walls which are inclined from the outside to the central region provides a reduced frontal area should the raft or one side of the raft be lifted out of the water.

If the pocket wall is secured to the life-raft at a central position or a number of other positions as well as at the circumferential edge then a more stable ride can be achieved.

In a preferred embodiment of the invention a central support 24 is provided between the floor of the raft and the pocket wall. This is shown chain dotted in Figure 1 and is illustrated in Figures 2 to 4.

This support acts as a mechanical opening means for the pocket and provides a positive means of unfolding the pocket during inflation. Typically the support member may be a semi-rigid tube, for example a plastics hose pipe. The support member also serves to prevent water being pumped into or out of the pocket by sea movement.

Figures 2 to 4 illustrate diagrammatically three stages of the pocket opening process occurring during inflation from which it will be seen that as the peripheral tube inflates it expands in diameter and causes the floor and the pocket to unfold. Since the support member is attached to both the floor and the pocket wall then this tube is inclined as the floor unfolds and has the effect of opening the pocket by displacing the wall downwards away from the base of the raft. This inflation occurs whilst the raft is in the water and thus as the pocket unfolds and opens water is admitted through the water inlet vents. Thus the stabilisation pocket becomes effective after inflation and this reduces the likelihood of the life raft over-turning.

In an alternative embodiment not illustrated the mechanical opening means is at least one ballast weight secured to the pocket wall in a central position. Conveniently the ballast weight is lead shot. The ballast weight may be provided in addition to the support member.

Whilst the invention has been described with reference to a pentagonal shaped life-raft it will be appreciated that any other convenient shape may be used for example circular, rectangular or oval. In each case the stabilisation pocket would besubstan- tially co-extensive with the base of the life-raft and would be secured to the periphery of the life-raft.

As an alternative to the described embodiment the water inlet vents may be in the form of slots in the pocket wall and the entire circumferential edge of the pocket wall may be glued or otherwise secured to the life-raft.

In a further envisaged embodiment the stabilising pocket may be sub-divided into a plurality of pockets, for example radial sectors, the dividing wall between each sector serving to connect the coextensive pocket wall to the floor of the life-raft.

In a further alternative embodiment a preferably centrally positioned tubular sleeve is secured to the pocket wall and to the floor of the life-raft.

One end of the sleeve, that end attached to the pocket wall is closed, whilst that end of the sleeve attached to the floor is open. The opening permits the insertion of a rod whereby the pocket wall may be displaced unfolding the pocket. Conveniently the tubular sleeve is constructed from a textile material.

Claims (11)

1. An inflatable life-raft comprising a base including a floor secured to and surrounded by an inflatable peripheral tube, a collapsable pocket located beneath and co-extensive with the base of the raft, and water inlets or openings adjacent to the inflatable peripheral tube to admit water to the pocket to stabilisethe raft.

2. A life-raft as claimed in claim 1, in which a tubular sleeve is secured between the pocket wall, which serves to close one end of the sleeve, and the floor of the life-raft and an opening is provided in the floor whereby a rod may be inserted into the sleeve to unfold the pocket.

3. An inflatable life-raft as claimed in claim 1 or 2, in which mechanical opening means are arranged between the floor of the raft and a wall of the pocket to facilitate unfolding of the pocket.

4. An inflatable life-raft as claimed in claim 3, in which the mechanical opening means comprises a semi-rigid tube attached at one end to the floor by a moulded rubber base piece.

5. A life-raft as claimed in claim 3, in which the mechanical opening means comprises ballast weights secured to the wall of the pocket.

6. A life-raft as claimed in any of claims 1 to 5, in which the pocket is secured at spaced intervals around its circumference to the peripheral tube and the water inlets are formed between the circumferential edge of the pocket wall and the base between the respective securing points.

7. A life-raft as claimed in any of claims 1 to 5, in which the water inlets comprise a plurality of spaced apertures formed in the pocket wall adjacent to its radially outermost edge.

8. A life-raft as claimed in any preceding claim, in which further water inlet openings are provided in a central region of the pocket wall.

9. A life-raft as claimed in any of the preceding claims, in which a plurality of radially disposed fabric walls are secured between the floor of the raft and the pocket wall, the radial walls serving to divide the pocket into several discrete pockets for improved stabilisation and to secure the co-extensive pocket wail to the floor of the life-raft.

10. A life-raft as claimed in any preceding claim, in which the pocket is made of a light weight textile fabric.

11. An inflatable life-raft constructed and arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.