Did u know : Pisces III: A dramatic underwater rescue

http://www.bbc.co.uk/news/magazine-23862359

Forty years ago two British sailors plunged almost 1,600ft into an abyss, 150 miles off Ireland, in a deep-sea submersible. Trapped in a 6ft-diameter steel ball for three days, the men had only 12 minutes of oxygen left when they were finally rescued.

The story of Pisces III, which made headlines at the time, is now largely forgotten.

But on Wednesday 29 August 1973 former Royal Navy submariner Roger Chapman, then 28, and engineer Roger Mallinson, then 35, plunged to the bottom of the Atlantic ocean in an accident, sparking a 76-hour international rescue operation.

Pisces III was used to lay transatlantic telephone cable on the sea bottom off Ireland in 1973. When a buoyancy tank was inadvertently flooded, it sank to the bottom of the ocean with its two-man crew, Britons Roger Mallinson and Roger Chapman, stranded at a depth of 1,575 feet (480 m) and 72 hours of available life support, which they were able to extend to 76 hours by careful conservation.

Initial rescue efforts by Pisces III sister submersibles were unsuccessful. Through an international effort of the United States, Canada, and Great Britain, the U.S. Navy Cable-controlled Undersea Recovery Vehicle (CURV-III) was deployed within 24 hours 6,000 miles from its home base. Deployment of CURV-III from CCGS John Cabot was hampered by heavy sea conditions. Rapid repairs were made when CURV-III’s gyroscope failed and electronics shorted-out after green water came aboard the Cabot. Assisted by the submersibles Pisces II and Pisces V, CURV-III was able to attach lines to the Pisces III hatch. The Cabot raised CURV-III at 60 to 100 feet (18 to 30 m) per minute until their lines entangled. The lines were cut, CURV-III was abandoned, and Pisces III was floated to 60 feet (18 m) where scuba divers were able to attach lines that were used to lift Pisces III the rest of the way to the surface. CURV-III performed the deepest underwater rescue in history when Pisces III’s two-man crew was rescued after 76 hours with just minutes of air remaining.