I-10 was an Imperial Japanese Navy Type A1 submarine that served during World War II. Designed as a submarine aircraft carrier, she was commissioned in 1941 and supported the attack on Pearl Harbor, operated in the Indian Ocean — including support for the 1942 midget submarine attack on Diego Suarez — and in the New Caledonia and New Zealand areas, and took part in the Guadalcanal campaign and Marianas campaign before she was sunk in 1944 during her seventh war patrol. Design and description Type A1 submarines were versions of the preceding Type J3 with superior range and an improved aircraft installation, and they were fitted as squadron flagships. They displaced on the surface and submerged. The submarines were long and had a beam of and a draft of . They had a diving depth of . For surface running, Type A1 submarines were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the Type A1s had a range of at ; submerged, they had a range of at . Type A1 submarines were armed with four internal bow torpedo tubes and carried a total of 18 torpedoes. They were also armed with a single /40 deck gun and two twin Type 96 anti-aircraft guns. Unlike on the Type J3 submarines, the aircraft hangar was integrated into the conning tower and faced forward, and the aircraft catapult was forward of the hangar, while the deck gun was aft of the conning tower. Reversing the locations of the deck gun and catapult allowed aircraft launching from a Type A1 submarine to use the forward motion of the submarine to supplement the speed imparted by the catapult. Construction and commissioning Built by Kawasaki at Kobe, Japan, I-10 was laid down as Submarine No. 10 on 7 June 1938. Later renamed I-10, she was launched on 20 or 29 September 1939, according to different sources, and was completed and commissioned on 31 October 1941. Service history Pre-World War II On the day of her commissioning, I-10 was attached to the Sasebo Naval District and assigned to Submarine Squadron 2 in the 6th Fleet. By 10 November 1941, she was serving as the squadron's flagship. That day, the 6th Fleet commander, Vice Admiral Mitsumi Shimizu, held a meeting with the commanding officers