- 2 * Kawasaki 12Ｖ 25/25 SB-type diesel engines diesel-electric
- 4 * Kawasaki Kockums V4-275R Stirling engines — up to Shōryū
- 3,900 hp (2,900 kW) surfaced
- 8,000 hp (6,000 kW) submerged
- 1 * shaft
- ZPS-6F surface/low-level air search radar
- Hughes/Oki ZQQ-7 Sonar suite:
- 1 * bow-array
- 4 * LF flank arrays
- 1 * Towed array sonar
- ZLR-3-6 ESM equipment
- 2 * 3-inch underwater countermeasure launcher tubes for launching of Acoustic Device Countermeasures
- 6 * HU-606 21 in (533 mm) torpedo tubes with 30 reloads for:
- 1) Type 89 torpedo
- 2) Harpoon (missile)
The Soryu class is a new class of Japanese diesel-powered attack submarines. It evolved from Oyashio class design. The name Soryu means Blue Dragon. The first boat was named after Japanese Imperial Navy aircraft carrier Soryu. It was commissioned in 2009. All other boats of this class are also named after Japanese mythological creatures. The Soryu class boats replaced in service the older Harushio class diesel-powered attack submarines. The Japan Maritime Self-Defense Forces (JMSDF) plans to operate at least 14 of these diesel-electric attack submarines.
The Soryu class boats are significantly larger than Oyashios. Furthermore these submarines have a larger displacement than any previous Japanese submarines since the World War II.
It can be distinguished from the Oyashio class by the X-shape rudders. Such rudder configuration was first used on the Swedish Gotland class. It is computer aided and provides the submarine with extreme maneuverability. It also enables to operate very close to seabed.
Submarines have hydrodynamic design and are fitted with anechoic coating. Interior also has sound isolation of loud components. Japan used top-secret stealth technology on these boats.
The Soryu class submarines are armed with six 533 mm torpedo tubes for the Type 89 torpedoes and UGM-84 Sub-Harpoon anti-ship missiles. Boats have high automation in combat systems.
Theses vessels are powered by a Swedish-made Stirling air-independent propulsion system. The Soryu is significantly larger than Oyashio class boats, in order to incorporate this propulsion system. This system is license-produced by Kawasaki Heavy Industries. It allows to stay submerged for longer periods of time without surfacing to charge the batteries. Submerged endurance is increased from days to weeks. It also enhanced vessel's stealth and operational capabilities. The Soryu class has an all-weather snorkel system that can operate even during a typhoon.
The AIPS develops 3 900 hp surfaced and 8 000 hp submerged. Power is delivered through one shaft.
Latest Soryu class submarines, including the SS-511 Oryu and SS-512 Toryu use a new lithium-ion battery propulsion technology. These are the first submarines in the world to use this technology. Currently it is one of Japan's most guarded military technologies. The use of lithium-ion batteries instead of the lead-acid batteries have almost doubled the electrical storage capacity and decreased the time required to recharge. Also the amount of batteries carried was increased as the Stirling air independent propulsion system was removed and replaced with additional lithium-ion batteries. This significantly improved underwater endurance over the previous Soryu class boats, as well as other most advanced diesel-electric submarines.