Uzushio-class submarine

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 submarine. Many were converted to training submarines (ATSS) towards the end of their lives.

General characteristics
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 m. The submarines measured 72.0 m long between perpendiculars and 9.9 m at the beam. They had a maximum draught of 7.5 m and had a standard displacement of 1850 t and a 3600 t displacement when submerged.

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 3400 BHP surfaced and 7200 SHP submerged. This gave the boats a maximum speed of 12 kn surfaced and 20 kn dived. 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.

The Uzushios were armed with Japanese Type 89 torpedoes fired from six 533 mm torpedo tubes located amidships. 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 or SQS-4 active sonar.