Roger Chapman, who has died aged 74, survived the world's longest and deepest underwater rescue. In the early hours of August 29, 1973, Chapman and Roger Mallinson, pilots of Pisces III, a six-foot diameter submersible, began a routine dive to 1,600 ft, some 150 miles south-west of Cork. Their task was to use waterjets to liquefy the mud and bury a transatlantic telephone cable.
With the job done after eight hours, Pisces III was about to be lifted into their mother ship, Vickers Voyager, when the towline snagged and wrenched open the hatch to a self-contained compartment.
Water flooded in and Pisces III sank to the seabed; at 175ft the towline broke, and as the submersible plunged to the bottom, the pilots shut off the electrical systems, released a 400lb ballast weight and braced themselves for impact. They hit the bottom at about 40 mph, their vessel burying itself stern-first in the mud at an angle of 85 degrees.
They had about three days of oxygen, a sandwich and a can of lemonade. They made themselves as comfortable as possible, Chapman recalling: "Our job was to act as vegetables most of the time, but still perform as intelligent human beings every half an hour for essential life support jobs."
An international rescue swung into action. The survey ship Hecate arrived on the scene; Pisces II was brought from the North Sea, while the US Navy flew in its Controlled Underwater Recovery Vehicle, CURV-III, and the Royal Canadian Navy their Pisces V.
After two days, during which the rescuers made several unsuccessful attempts to attach a lifting line, Chapman and Mallinson were cold, wet, disorientated and suffering severe headaches.
Only on the third day did Pisces II and CURV-III succeed in fixing lifting tackle. Pisces III finally broke the surface: later it was determined that there was only 12 minutes of oxygen left.
Roger Ralph Chapman was born in Hong Kong on July 29, 1945 and joined the navy in 1963. He volunteered as a submariner in 1967 but left the service after his eyesight deteriorated.
He then founded Sub Sea Systems, operating two-man submersibles engaged in the protection of subsea telephone cables, which were proving susceptible to ever-deeper trawling on the continental shelf.
His company was bought by Vickers Oceanics and Chapman was appointed manager of the survey department.
After his escape, Chapman established Rumic to pioneer a new generation of manned and unmanned submersibles. Inspired by Chapman's experience in Pisces III, the company developed the LR5, a manned submersible, designed for rescuing 16 men at a time from stranded submarines, and operated Scorpio-class submersibles.
In 2000 the LR5 mobilised as part of a British rescue mission after the Russian submarine Kursk sank in the Barents Sea. However, Kremlin prevarication delayed its deployment and all the crew died. Then in 2005, when the Russian submersible PRITZ AS28 became snagged in wires and sank to the bottom of the Pacific, Scorpio-45 effected a successful rescue.
Rumic was honoured by President Vladimir Putin, and the following year Chapman was appointed CBE. A natural entrepreneur Chapman was a loyal and generous friend and a mentor to many. In 1975 he wrote No Time on our Side, a moving account of his rescue ordeal.
In 1971 he married June Sansom, who survives him with their two sons.
Roger Chapman died on January 24.