IJN I-400

Survived

Type	Submarine
Class	Sen-Toku (I-400)
War	Second World War
Main guns	1 × 5.5″ gun

The largest submarines built until the nuclear age, carrying three Seiran floatplanes to bomb the Panama Canal or the US coast. Surrendered at sea in August 1945 before making an attack, and scuttled by the US Navy off Hawaii in 1946.

The United States Navy submarine tender USS Proteus (AS-19) (left) and Imperial Japanese Navy submarines Japanese submarine I-14 2 (center) and Japanese submarine I-400 2 (right) in port in Japan after the end of World War II. Photo: AnonymousUnknown author, Public domain · Wikimedia Commons

Armament and specifications

Armament

8 × 533 mm (21 in) forward torpedo tubes
20 × Type 95 torpedoes
1 × 14 cm/40 11th Year Type naval gun
3 × 25 mm (1.0 in) 3-barrel machine gun
1 × Type 96 25 mm (0.98 in) machine gun

Builder	Kure Naval Arsenal, Kure, Japan
Laid down	18 January 1943
Launched	18 January 1944
Commissioned	30 December 1944
Displacement	5,223 long tons (5,307 t) surfaced 6,560 long tons (6,665 t) submerged
Length	122 m (400 ft)
Speed	18.75 knots (21.58 mph; 34.73 km/h) surfaced 6.5 kn (7.5 mph; 12.0 km/h) submerged
Complement	144

As built, from the ship's Wikipedia article. Figures there may cover later refits too.

Career

She isn't listed in any of the fleet actions covered here.

Launched

18 January 1944