Survival Platform

Abstract

A survival platform, comprising two flexible outer sheets ( 4, 5 ), the outer sheets each having a circumference ( 2 ) and being sealed together at their circumferences ( 2 ) to define a void ( 18 ) therebetween, the survival platform further comprising an inner flexible sheet ( 6 ) interposed between the outer sheets ( 4, 5 ) and dividing the void ( 18 ) into two sub-voids ( 18 a, 18 b ), and means ( 8 ) for inflating the survival platform by introducing a gas into the void to increase a gas pressure therewithin, in which the inner sheet ( 6 ) is arranged such that, should one of the outer sheets ( 4, 5 ) be breached at a breach, the gas pressure within the void will tend to force the inner sheet ( 6 ) through the breach, thereby to block the breach and reduce the level to which gas escapes through the breach.

What is claimed: 
     
         1 . A survival platform, comprising two flexible outer sheets, the outer sheets each having a circumference and being sealed together at their circumferences to define a void therebetween, the survival platform further comprising an inner flexible sheet interposed between the outer sheets and dividing the void into two sub-voids, and means for inflating the survival platform by introducing a gas into the void to increase a gas pressure therewithin, in which the inner sheet or outer sheet is arranged such that, should one of the outer sheets be breached at a breach, the gas pressure within the void will tend to force the inner sheet through the breach, thereby to block the breach and reduce the level to which gas escapes through the breach, and in which the survival platform is provided with a flexible skirt extending from the circumferences of the outer sheets. 
     
     
         2 . The survival platform of  claim 1 , in which the skirt extends entirely around the circumferences. 
     
     
         3 . The survival platform of  claim 1 , in which the sub-voids are sealed with respect to each other. 
     
     
         4 . The survival platform of  claim 1 , comprising a plurality of reed members, each reed member comprising an elongate body having a length, each reed member joining an outer sheet to the inner sheet along the length, with both outer sheets being joined to the inner sheet by reed members. 
     
     
         5 . The survival platform of  claim 4  in which the reed members are provided in pairs, with one reed member of each pair joining one of the outer sheets to the inner sheet and the other reed member of each pair joining the other outer sheet to the inner sheet at the same position on the inner sheet but on the opposite face. 
     
     
         6 . The survival platform of  claim 4 , in which each reed member comprises a tubular body having two opposing faces, one face being joined to an outer sheet and the other face being joined to the inner sheet. 
     
     
         7 . The survival platform of  claim 6 , in which the tubular body is formed by folding a planar member in two, such that the planar member touches itself at a join. 
     
     
         8 . The survival platform of  claim 1 , in which the inner sheet has a circumference, and is joined to the outer sheets at their circumferences. 
     
     
         9 . The survival platform of  claim 1  which, when inflated, is substantially planar and so defines a plane, about which the survival platform is symmetrical, or at least substantially symmetrical. 
     
     
         10 . The survival platform of  claim 1 , in which the freeboard of the survival platform is at most 25 cm, preferably at most 15 cm or 10 cm.