Japanese submarine I-181

Sister ship I-176 at sea in 1942
History
Empire of Japan
Name	Submarine No. 159
Builder	Kure Naval Arsenal, Kure, Japan
Laid down	11 November 1941
Renamed	I-81
Launched	2 May 1942
Renamed	I-181 on 20 May 1942
Completed	24 May 1943
Fate	Missing after 13 January 1944
Stricken	30 April 1944
General characteristics
Class and type	Kaidai type, KD7-class
Displacement	1,862 t (1,833 long tons) surfaced 2,644 t (2,602 long tons) submerged
Length	105.5 m (346 ft 2 in)
Beam	8.25 m (27 ft 1 in)
Draft	4.6 m (15 ft 1 in)
Installed power	8,000 bhp (5,966 kW) (diesels) 1,800 hp (1,342 kW) (electric motors)
Propulsion	Diesel-electric 2 × diesel engines 2 × electric motors
Speed	23 knots (43 km/h; 26 mph) surfaced 8 knots (15 km/h; 9.2 mph) submerged
Range	8,000 nmi (15,000 km; 9,200 mi) at 16 knots (30 km/h; 18 mph) surfaced 50 nmi (93 km; 58 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged
Test depth	80 m (262 ft)
Complement	86
Armament	6 × 533 mm (21 in) torpedo tubes (all bow) 1 × 120 mm (4.7 in) deck gun 1 × twin 25 mm (1.0 in) Type 96 AA gun

I-181 (originally I-81) was an Imperial Japanese Navy Kaidai-type cruiser submarine of the KD7 sub-class commissioned in 1943. During World War II, she conducted two war patrols, rescued the United States Marine Corps ace Gregory "Pappy" Boyington, and took part in the New Guinea campaign before American warships sank her in January 1944.