Inspired by the successful 1941 attack (carried out by Italian divers riding ‘chariots’ armed with detachable explosive warheads) on the British battleships, ‘Queen Elizabeth’ and ‘Valiant’, in Alexandria Harbour, the Royal Navy began to devote greater resources to training divers for offensive missions.
In 1942 – using modified oxygen sets originally designed for submarine escape (Davis Submarine Escape Apparatus) – volunteers were subjected to oxygen tolerance tests in the ‘wet’ and ‘dry’ recompression chambers at the Siebe, Gorman factory, in the U.K..
Intended to see how deep a diver could go to avoid boom-defence and anti-submarine nets, the tests often involved simulated dives to, say, seventy-feet for twenty-minutes, followed by ten-feet for five-minutes, and then down to fifty-feet for thirty-minutes before ‘surfacing’; depths that today – in light of greater knowledge regarding oxygen toxicity – would be regarded as lunacy.
Quickly learning to recognise the onset of oxygen toxicity symptoms – the early warning signs then being regarded as a ‘twitching of the lips’ – and rapidly ascending to a supposedly safer depth, the volunteers frequently passed out and had to be revived.
Jokingly referring to oxygen poisoning as the act of a demon that they called, ‘Oxygen Pete’; one diver even composed a poem to the imaginary fiend;
“For down at the depth of seventy feet
Lives a guy by the name of ‘Oxygen Pete’.“