Joseph Salim Peress

Infobox Engineer

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name = Joseph Salim Peress
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birth_date = 1896
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death_date = June 4 1978
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significant_design = Atmospheric diving suit
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Joseph Salim Peress (1896 – June 4 1978), was a pioneering British diving engineer, inventor of one of the first truly usable atmospheric diving suits, the "Tritonia", and was involved in the construction of the famous JIM suit.

Peress had a natural talent for engineering design, and had challenged himself to construct an articulated atmospheric diving suit (ADS) that would keep divers dry and at atmospheric pressure, even at great depth. At the time, little was known about decompression diving. Various atmospheric suits had been developed during the Victorian era, but nobody had yet managed to overcome the basic design problem of constructing a joint which would remain flexible and watertight at depth without seizing up under pressure.

In 1918 Peress began working for WG Tarrant at Byfleet, United Kingdom, where he was given the space and tools to develop his ideas about constructing an ADS. His first attempt was an immensely complex prototype machined from solid stainless steel.

In 1923 Peress was asked to design a suit for salvage work on the wreck of the P&O liner SS Egypt which had sunk in 122m of water off Ushant. He declined, on the grounds that his prototype suit was too heavy for a diver to handle easily, but was encouraged by the request to begin work on a new suit using lighter materials. By 1929 he believed he had solved the weight problem, and had also managed to improve the design of the suit's joints.

Peress was approached by a Greek industrialist seeking "deep diving armor", and accepted the commission. The resulting Tritonia suit demonstrated a great deal of innovation: cast magnesium was used in the main body, as it had a better strength to weight ratio than steel, and the joints had been redesigned to use a piston sealed with leather washers moving in an annular semi-hemispherical cylinder.

By May 1930 Peress had completed trials and the Tritonia suit was publicly demonstrated in a tank at Byfleet. In September Peress' assistant Jim Jarret dived in the suit to a depth of 123m in Loch Ness. The suit performed perfectly, the joints proving resistant to pressure and moving freely even at depth.

Peress' Greek client opted not to use the suit, so it was offered instead to the Royal Navy which turned it down, stating that Navy divers never needed to descend below 90m.

Jim Jarret made a deep dive to 90m on the wreck of the Lusitania off south Ireland, followed by a shallower dive to 60m in the English Channel in 1937 after which, due to lack of interest, the Tritonia suit was retired. Peress abandoned work on diving suits and instead to pioneering work in plastic moulding, and later forming a company which became the world's largest manufacturer of gas turbine blades for the aircraft industry.

In 1969 Peress became a consultant to the new company created to develop the JIM suit, which was named after his diver Jim Jarret.