Inspired by the successful 1941 attacks – carried out by Italian divers riding ‘chariots’ armed with detachable explosive warheads – on the British battleships, ‘H.M.S.Queen Elizabeth’ and ‘H.M.S.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 & Co.’s factory, at Chessington, 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’.“
It was, apparently, the last time that human ‘guinea-pigs’ were used in the study of oxygen.