Submarine 707R(サブマリン707R)

Submarine 707R is a two-episode anime OVA produced by Group TAC and Sony and also a manga released by Satoru Ozawa released in 1963-1965 on Weekly Shōnen Sunday and although not a mecha robot series, a "mecha" storyline that spawned plastic models during its time. The manga series was very intriguing for its time as it was a unique story that featured various submarines with a storyline that introduced readers to anti-submarine warfare, homing torpedoes, sonars and technical topics in relation to submarines. Due to its popularity, reception of the OVA adaptation has been mixed.