The Sen Toku I-400-class (伊四百型潜水艦 I-yonhyaku-gata Sensuikan?) Imperial Japanese Navy submarines were the largest submarines of World War II and remained the largest ever built until the construction of nuclear ballistic missile submarines in the 1960s. They were submarine aircraft carriers able to carry three Aichi M6A Seiran aircraft underwater to their destinations. (Sources : Wikipedia)
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