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. The vehicles have multiple view ports, sample collecting, environmental sensing, and instrument placement capabilities. The pressure hull has a inside diameter and is made of HY-100 steel with 3 forward-looking acrylic windows, 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 being used to bury cable and repeaters of the CANTAT-2transatlantic 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 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 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 per minute until their lines entangled. The lines were cut, CURV-III was abandoned, and Pisces III was floated to 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 VI was purchased out of storage from International Underwater Contractors in 2015. Currently Pisces VI is undergoing a complete refit in Salina, Kansas. Pisces VI is being reengineered to provide a versatile deep water platform to meet the needs of the underwater research community.
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, NOAA’s Undersea Research Center at the University of Hawaii School of Ocean & EarthScience & Technology.
Of the two Russian-owned submersibles, Pisces VII and XI, VII is on display at the Museum of the World Ocean in Kaliningrad, next to the research vessel Vityaz; XI is kept in storage, with some of its parts used as spare parts for the MIR submersibles.
