The Uzushio-class submarine was a series of seven submarines in service with Japanese Maritime Self Defense Force during the Cold War between 1972 and the mid-1990s. They were the first generation of the teardrop type submarine that valued the underwater performance against that of the preceding conventional-hull type Asashio class. Many were converted to training submarines (ATSS) towards the end of their lives.
The Uzushio class was the first Japan Maritime Self-Defense Force submarine design to incorporate the teardrop hull. The Uzushios had a double hull construction which used NS-63 high-tensile steel to allow for a deeper diving depth of 200 metres (660 ft). The submarines measured 72.0 metres (236 ft 3 in) long between perpendiculars and 9.9 m (32 ft 6 in) at the beam. They had a maximum draught of 7.5 m (24 ft 7 in) and had a standard displacement of 1,850 tonnes (1,820 long tons) and a 3,600 t (3,500 long tons) displacement when submerged.[1][2][a]
The submarines were powered by a diesel-electric system composed of two Kawasaki-MAN V8V24/30AMTL diesel engines and two electric motors turning one shaft creating 3,400 brake horsepower (2,500 kW) surfaced and 7,200 shaft horsepower (5,400 kW) submerged.[1][b] This gave the boats a maximum speed of 12 knots (22 km/h; 14 mph) surfaced and 20 knots (37 km/h; 23 mph) dived.[1][2] The submarines incorporated a separate emergency blowing system to all the vessels to surface rapidly and had a 3D automatic steering system which combined automatic depth and automatic direction maintenance systems.[1]
The Uzushios were armed with Japanese Type 89 torpedoes fired from six 533-millimetre (21 in) torpedo tubes located amidships.[3] The submarines had their sonar array located in the bow which was composed of a ZPS-4 surface search sonar, a ZQQ-2, ZQQ-3, or ZQQ-4 passive/active search sonar suite and a SQS-36J[2][3] or SQS-4 active sonar.[3]