noun
special-purpose submarine; midget submarine
Primarily refers to Japanese midget submarines used in World War II, such as the Type A Kō-hyōteki. A historical military term.
真珠湾攻撃では特殊潜航艇も投入された。
Special-purpose submarines were also deployed in the attack on Pearl Harbor.
特殊潜
There is an exhibit of midget submarines at the war museum.