Type A1 submarine

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The , also called were a trio of aircraft-carrying cruiser submarines built for the Imperial Japanese Navy (IJN) during the 1930s. All three participated in the Pacific War and were lost.

Design and description

The submarines of the A1 type were versions of the preceding J3 class with superior range, improved aircraft installation. Unlike the earlier boats, they were equipped with extensive communication facilities to allow them to serve as squadron flagships. They displaced Template:Convert surfaced and Template:Cvt submerged. The submarines were Template:Convert long, had a beam of Template:Convert and a draft of Template:Convert. They had a diving depth of Template:Convert.

For surface running, the boats were powered by two Template:Convert diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a Template:Convert electric motor. They could reach Template:Convert on the surface and Template:Convert underwater. On the surface, the A1s had a range of Template:Convert at Template:Convert; submerged, they had a range of Template:Convert at Template:Convert.

The boats were armed with six internal bow Template:Convert torpedo tubes and carried a total of 18 torpedoes. They were also armed with a single 40-caliber [[14 cm/40 11th Year Type naval gun|Template:Convert]] deck gun and two twin [[Type 96 25 mm AT/AA Gun|Template:Convert Type 96]] anti-aircraft guns.

Unlike the J3 class, the aircraft hangar was integrated into the conning tower and faces forward; the positions of the deck gun and the catapult were exchanged so the aircraft could use the forward motion of the ship to supplement the speed imparted by the catapult. The hangar could be accessed from inside the pressure hull and the floatplane was stowed with its wings folded.

Boats

• was sunk by destroyer USS Frazier in the Aleutians on 11 June 1943.
• was sunk by destroyer USS David W. Taylor and destroyer escort USS Riddle east of Saipan on 4 July 1944.
• disappeared south of Funafuti after 11 January 1944. The I-11 probably struck a mine laid by USS Terror.

Two more boats were ordered under the 1942 Naval Program, but were later cancelled.