On October 17, the Japan Maritime Self-Defense Force (JMSDF) marked a significant milestone with the launch of its fourth Taigei-class attack submarine, named Raigei (pennant number SS 516), during a ceremony at the Kobe Works, Kawasaki Heavy Industries facilities in Kobe City. This new 3,000-tonne diesel-electric submarine is powered by cutting-edge Kawasaki 12V 25/31 diesel engines, boasting remarkable output power. The construction cost of the Raigei submarine was approximately 70.2 billion yen ($470 million), and it is expected to enter active service in March 2025. The name “Raigei” translates to “thunder whale” in Japanese, in keeping with the tradition of incorporating “Gei” (whale) in the names of Taigei-class submarines. This class, aptly named “Big Whale,” represents a significant advancement in Japan Maritime Self-Defense Force (JMSDF) capabilities.
The Taigei-class submarines (29SS), known as the “Big Whale” series, are a novel addition to Japan’s naval fleet, developed for the Japan Maritime Self-Defense Force, following the Soryu class. The lead submarine, Taigei (SS 513), was commissioned in March 2022, while the second, Hakugei (SS 514), entered service in March 2023. The third, Jingei (SS 515), is expected to join the fleet in March 2024. These submarines are equipped with an impressive array of lithium-ion batteries, similar to the Oryu and Toryu submarines, granting them extended underwater endurance and speed capabilities compared to conventional diesel-electric submarines. The Kyoto-based developer and manufacturer of battery systems GS Yuasa provided the lithium-ion batteries for those new submarines.
These submarines have a length of 84 meters, a draught of 10.4 meters, and a beam of 9.1 meters, with a displacement of 3,000 tons, providing accommodation for a crew of 70 personnel. the Taigei-class submarines are approximately 100 tons heavier, incorporating state-of-the-art equipment such as advanced sonar systems and a snorkel power generation system. Notable features include the X-shaped rudder for improved submerged operations and propulsion performance, as well as advanced acoustic absorbent materials and a floating floor structure for silent underwater operation. The pressure hull is constructed from high-strength steel, ensuring resilience under high water pressure during deep-sea missions.
Armed with six HU-606 533mm torpedo tubes capable of launching Mitsubishi-built Type 89 heavyweight homing torpedoes and UGM-84 Harpoon anti-ship missiles, the Taigei-class submarines are well-equipped for both anti-submarine and anti-ship operations. Their armament includes the Type 18 torpedo, a successor to the Type 89 torpedo. They also feature torpedo countermeasures to enhance survivability in hostile situations. The propulsion system consists of a single-shaft diesel-electric setup, powered by two Kawasaki 12V 25/25 SB-type diesel engines and an electric propulsion motor. These advancements in technology make the Taigei-class submarines formidable assets in Japan’s maritime defense strategy.