Pisces-class deep submergence vehicle

Pisces class submersibles are three person research deep-submergence vehicles designed and built by Hyco International Hydrodynamics of North Vancouver in British Columbia with a maximum operating depth of 2,000 m (6,560 ft). The vehicles have multiple view ports, sample collecting, environmental sensing, and instrument placement capabilities. The pressure hull has an 7 ft inside diameter and is made of HY-100 steel with 3 forward-looking acrylic windows, 6 in in diameter. Designed by Alan Trice, the Pisces series of submersibles are representative of early manned submersibles built in the late 1960s and were proven workhorses in offshore exploration and oceanographic research. Pisces II was the first production model of the design and was completed in 1968, with 9 more Pisces subs built before the manufacturer folded in the late 1970s.

1973 Pisces III rescue
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 1575 ft 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 ft per minute until their lines entangled. The lines were cut, CURV-III was abandoned, and Pisces III was floated to 60 ft 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 12 minutes of air remaining.

Pisces IV and V
Pisces IV and Pisces V are currently operated for research by National Oceanic and Atmospheric Administration, based in Hawaii. Its mother ship, the R/V Kaimikai-o-Kanaloa launches Pisces V and its sister vessel Pisces IV from an A-frame hoist on its aft deck. Pisces IV, was built for the Soviet Union in 1971, but due to national security concerns from the United States that sensitive technology might be transferred to the Soviets, Canadian Government refused to issue the export permit and instead purchased it for its Department of Fisheries and Oceans. Both Pisces IV and V are currently operated by the Hawaii Underwater Research Laboratory, part of the US National Undersea Research Program. The second Pisces is kept on board in a ready state in case of an emergency.

Pisces VII and IX
Pisces VII and Pisces IX were built in 1975 and used by Shirshov Institute of Oceanology of the Academy of Sciences of the USSR for about 10 years, until being replaced by the MIR submersibles. Akademik Kurchatov, Dmitri Mendeleyev, and Akademik Mstislav Keldysh served as their support ships.

Current status of vehicles

 * Pisces II is currently on display at Deep Marine, a maritime museum highlighting the deep-sea technology legacy of Hyco at Deep Marine, located at the old Versatile Pacific Shipyards site on the waterfront at Esplanade and Lonsdale, in North Vancouver, British Columbia, Canada.


 * Pisces III is on display at Weymouth Sea Life Centre, Dorset United Kingdom.


 * Both Pisces IV and V have undergone recent upgrades and are operated by the Hawai‘i Undersea Research Laboratory (HURL), NOAA’s Undersea Research Center at the University of Hawaii School of Ocean & Earth Science & Technology.


 * Of the two Russian-owned submersibles, Pisces VII and XI, one is in a museum (an old research ship) in Kaliningrad, the other is kept in storage, with some of its parts used as spare parts for the MIR submersibles.