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 a 7 ft (2.1 m) inside diameter and is made of HY-100 steel with 3 forward-looking acrylic windows, 6 in (15 cm) in diameter. Designed by , the Pisces series of submersibles are representative of early crewed 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 bu