Japan grows next-generation submarine fleet

The Japan Maritime Self-Defense Force (JMSDF) has commissioned its third Taigei-class diesel-electric submarine on 8 March, JS Jingei (SS 515), the service announced on the same day.

According to the JMSDF, Jingei – which translates into ‘Swift Whale’ – was inducted into the Yokosuka-based Submarine Division 4 of Submarine Flotilla 2, shortly after a ceremonial handover by shipbuilder Mitsubishi Heavy Industries (MHI) at its Kobe City facility.

The Taigei-class SSK has an overall length of 84m, a beam of 9.1m, a draught of 10.4m, and a standard displacement of about 3,000 tonnes, which is comparable to the service’s in-service Soryu-class SSKs. It is operated by a crew complement of about 70 and has been designed to support female personnel.

Like the last two boats of the 12-strong fleet of Soryu-class SSKs, Oryu (SS 511) and Toryu (SS 512), the Taigei-class is equipped with lithium-ion batteries supplied by Kyoto-based GS Yuasa for extended underwater endurance and range. Japan is the first country to successfully field SSKs that employ lithium-ion battery technology, as opposed to conventional lead-acid batteries.

The Taigei-class alsos employ a new advanced combat management system (CMS) comprising integrated command and control (C2), sensors, and weapons systems. These include the OYX-1 processing system, ZQX-12 submarine tactical display system, ZQQ-8 fibre-optic array sonar system, NZLR-2 electronic support measures (ESM) system, and ZPS-6H radar system.

The first submarine in the class, JS Taigei (Big Whale), was converted to a test submarine on the same day.

Kawasaki Heavy Industries (KHI) launched the fourth Taigei-class boat, the future JS Raigei (Thunder Whale), in October 2023. Raigei is expected to enter JMSDF service in March 2025 following user acceptance trials. Unlike lead boat Taigei and sister boats Hakugei (White Whale) and Jingei, Raigei will be equipped with the latest Kawasaki 12V 25/31 diesel engines that offer a higher performance than the present Kawasaki 25/25SB powerplants.

by Jr Ng