The ''ST-class'' was a type of armored boat of the

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor o ...

that saw service during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. She was developed in 1940 (Showa 15) mainly for riverine patrol in China, a role that was previously served by the

Soukoutei-class armored boat The or AB-tei class was a type of armored gunboat used by the Imperial Japanese Army from 1928 to 1945 in the Second Sino-Japanese War and World War II. It was constructed of a metal hull and powered by a diesel engine. It was designated the "Ty ...

. The prototype was 11 meters long with a beam of 2.00 meters and a draught of 1.10 meters. Her speed was 9.65 knots. All ships were built at the

Yokohama is the second-largest city in Japan by population and the most populous municipality of Japan. It is the capital city and the most populous city in Kanagawa Prefecture, with a 2020 population of 3.8 million. It lies on Tokyo Bay, south of T ...

shipyard of

Mitsubishi Heavy Industries is a Japanese multinational engineering, electrical equipment and electronics corporation headquartered in Tokyo, Japan. MHI is one of the core companies of the Mitsubishi Group and its automobile division is the predecessor of Mitsubishi Mo ...

She was armed with a 37 mm gun ( :jp:狙撃砲).

References

Ships of the Imperial Japanese Army Ships built by Mitsubishi Heavy Industries {{WWII-stub