Japan Launches Fifth Taigei-Class Submarine for JMSDF
Japan's defense capabilities received a significant boost on October 4, 2024, with the launch of the fifth Taigei-class submarine, Chogei (SS 517), at Mitsubishi Heavy Industries' (MHI) Kobe Shipyard. Weighing in at 3,000 tonnes, this cutting-edge diesel-electric submarine marks a key advancement in Japan's maritime defense strategy, particularly for the Japan Maritime Self-Defense Force (JMSDF). The Taigei-class subs have been built to enhance Japan’s stealth, surveillance, and combat operations. Chogei, like its predecessors, is a symbol of Japan’s technological prowess in undersea warfare.
What Sets Chogei Apart?
The Chogei, named after the "long whale," is the third vessel in Japanese history to carry this name, continuing Japan’s tradition of naming its submarines with marine life-inspired names. It's slightly larger than the previous Soryu-class submarines, featuring a standard displacement of 3,000 tonnes compared to the 2,950 tonnes of the Soryu-class. At 84 meters in length and 9.1 meters in beam, Chogei is designed for stealth and power.
The launch of Chogei is part of a broader program aimed at modernizing the JMSDF’s submarine fleet, which plays a crucial role in Japan’s defense strategy, particularly given the complex security environment in the Asia-Pacific region.
Key Specifications and Innovations
1. Powerful New Diesel Engines:
Chogei is equipped with two Kawasaki 12V 25/31 diesel engines, which are a key upgrade over the previous models. These high-output engines, first introduced on the fourth Taigei-class submarine, Raigei, provide better efficiency, enhanced performance, and higher durability. The engines are compatible with a new snorkel system, designed to generate power more effectively while reducing the submarine's acoustic signature, making it harder for enemies to detect.
2. Advanced Battery System:
Like other Taigei-class submarines, Chogei runs on lithium-ion batteries provided by GS Yuasa. This shift from traditional lead-acid batteries marks a breakthrough in the performance of Japan's submarines, extending their operational range and allowing for longer, quieter submerged operations. Japan is a pioneer in this technology, with South Korea planning to follow suit for their KSS-III Batch-II submarines.
3. Enhanced Combat Systems:
The Taigei-class submarines are equipped with an advanced combat management system (CMS) integrating sensors, weapons, and command-control systems to provide superior situational awareness. These systems include a fiber-optic sonar array that offers improved detection of enemy vessels and underwater threats. Moreover, the Chogei is designed to carry Japan’s most advanced torpedo, the Type 18, which has improved propulsion and detection capabilities over its predecessor, the Type 89.
4. Crew Comfort and Accommodation:
For the first time in Japanese naval history, the Taigei-class submarines incorporate female-only living quarters, a step toward a more inclusive service. The living space is equipped for up to six women, reflecting JMSDF's evolving demographics.
5. Stealth Features:
Stealth is paramount in modern submarine warfare, and Chogei has adopted several features to reduce its acoustic signature, including a redesigned snorkel and non-penetrating periscope produced by Mitsubishi Electric. These features contribute to a lower detection rate, making it more difficult for adversaries to locate the submarine.
Weapons and Future Capabilities
The Taigei-class submarines, including Chogei, are equipped with the latest Torpedo Countermeasures (TCM) system, which launches decoys to divert enemy torpedoes. Additionally, Japan is developing a new submarine-launched cruise missile to be installed on future submarines. This missile, with a range of up to 1,500 km, will allow Japan to strike enemy ships and land targets from great distances, significantly extending its strategic reach.
A Glimpse into the Future
Chogei is expected to enter service by March 2026, contributing to Japan’s undersea fleet's strength. The ongoing Taigei-class program highlights the rapid pace of development in Japan's naval capabilities. Notably, the cost of building Chogei stands at approximately 64.8 billion yen ($443 million), a reflection of the rising costs of submarine construction due to inflation and technological advancements.
Looking forward, the Japanese Ministry of Defense (MoD) has plans to build a new class of submarines with vertical launch systems (VLS) and long-range standoff missiles by the 2030s. These next-generation submarines will be larger and equipped with cutting-edge systems for enhanced combat operations, continuing Japan's trend of innovation in naval warfare.
The launch of Chogei marks another significant milestone in the modernization of Japan's submarine fleet. With its advanced diesel engines, lithium-ion batteries, and sophisticated combat systems, Chogei is a formidable asset for the JMSDF. As tensions rise in the Asia-Pacific region, Japan’s focus on expanding and upgrading its naval capabilities signals its intent to maintain a robust defense posture while adapting to new threats in undersea warfare.
