T-class and Gato submarines fit different missions

Japanese doctrine treated submarines as reconnaissance assets and fleet tripwires. A T-class boat carried a heavy torpedo attack for constrained waters and bases such as Singapore, making it an effective ambush predator. A Gato sacrificed some attack load for the range needed to cross the Pacific before beginning its patrol. Neither design was universally superior because each answered a different operational problem. The comparison extends to modern joint programs such as Type 26 derivatives, where allies can share hull architecture while tailoring weapons and sensors to national missions.