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 (18a, 18b), 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.