Japan’s Maritime Self-Defense Force (JMSDF) took delivery of the eighth Soryu-class diesel-electric attack submarine (SSK) from Kawasaki Heavy Industries (KHI) in Kobe on March 13, according to a company press release.
The boat, which has been named Sekiryu (Red Dragon), is the fourth Soryu-class boat to be built by KHI and the eighth SSK of the class in total. (Other boats were built by the Mitsubishi Heavy Industries in Kobe.) The March 13 ceremony was attended by the deputy minister of defense and the chief of staff of the Defense Agency.
KHI has built a total of 27 submarines following the end of World War II. Mitsubishi Heavy Industries (MHI) assembled 26 in the same timeframe. The latest Soryu-class boat’s keel was laid in March 2013. The submarine was launched in November 2015. As I reported elsewhere:
Overall, the JMSDF plans to induct a total of 12 Soryu-class submarines [construction of the last boat was approved under Japan’s fiscal year 2016 budget] by 2021. With a displacement of 4,100 tons when submerged, the Soryu-class is larger than any other sub class in service with the JMSDF and is Japan’s first class of air-independent propulsion submarines.
The new sub is powered by two Kawasaki 12V 25/25 SB-type diesel engines and four Kawasaki Kockums V4-275R Stirling engines. It has an estimated range of 6,100 nautical miles (11,297 kilometers) with a maximum surface speed of 13 knots and a subsurface travelling speed of 20 knots.
Interestingly, Japan will become the first nation to equip part of its submarine fleet with advanced lithium-ion batteries — the design of which is one of Japan’s top military secrets — in order to improve the submarine’s underwater endurance. Japan’s Ministry of Defense announced in 2015 that it plans to equip the next two Soryu-class submarines with lithium-ion batteries.
“At this moment Japanese submarines use lead-acid batteries as a source of power, but submarines being produced since the fiscal year 2015 will use lithium-ion batteries instead,” according to a statement by GS Yuasa, a Japanese battery maker, which is designing and building the lithium-ion batteries for the Soryu-class. Delivery of the batteries for the new submarines is expected for August 2018.
The boats hull is made of high tensile steel covered with anechoic coating. As I explained last year:
The Soryu-class ships’ hydrodynamic design is based on the older Oyashio-class diesel-electric attack submarines currently in service with the JMSDF. It is also fitted with a computer-controlled, Swedish-designed X rudder to increase the ship’s maneuverability when operating in shallow waters close to the seabed.
Soryu-class submarines are fitted with six HU-606 533 mm torpedo tubes that can accommodate Type 89 homing torpedoes and UGM-84 Harpoon anti-ship missiles. The boats crew consists of nine officers and 56 sailors.