The was a class of submarine in the Imperial Japanese Navy (IJN) which served during World War II. The Type-B submarines were similar to the Type-A apart from not having the headquarters installation.
The Type-B submarines were divided into four classes:
See main article: Type B1 submarine. Project number S37. Twenty boats were built between 1937 and 1944 under the Maru 3 Programme (Boats 37 - 42) and Maru 4 Programme (Boats 139 - 152).
| +Boats in class | |||||||
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Fate | |
| 37 | [1] | Kure Naval Arsenal | 25 January 1938 | 7 March 1939 | 30 September 1940 | Sunk by near San Cristóbal on 10 November 1942. | |
| 38 | Yokosuka Naval Arsenal | 18 April 1938 | 19 July 1939 | 24 January 1941 | Sunk by and maritime patrol aircraft at Nouméa -23.4333°N 220°W on 19 August 1943. | ||
| 39 | Mitsubishi, Kōbe Shipyard | 15 March 1938 | 16 September 1939 | 28 April 1941 | Sunk by in the Gilbert Islands on 25 November 1943. | ||
| 40 | Kawasaki, Kōbe Shipyard | 7 January 1939 | 24 February 1940 | 15 July 1941 | Missing near Tarawa after 27 November 1943. Possibly sunk by aircraft from on 29 November 1943. | ||
| 41 | Yokosuka Naval Arsenal | 8 December 1938 | 24 November 1939 | 27 September 1941 | Missing near the Hawaiian Islands after 24 February 1942, most likely due to a diving accident. | ||
| 42 | Mitsubishi, Kōbe Shipyard | 3 February 1939 | 8 June 1940 | 15 October 1941 | Missing near Espiritu Santo after 23 August 1943. Possibly sunk by on 25 August 1943. | ||
| 43 | The dummy for the naval budget of the . | ||||||
| 139 | Kure Naval Arsenal | 7 June 1939 | 10 April 1940 | 6 November 1941 | Missing east of the Philippines after 25 October 1944. Possibly sunk by on 26 October 1944. | ||
| 140 | Sasebo Naval Arsenal | 5 July 1939 | 6 June 1940 | 24 February 1942 | Sunk by and in the Maldives at 0.95°N 88°W on 12 February 1944. | ||
| 141 | Mitsubishi, Kōbe Shipyard | 25 September 1939 | 17 December 1940 | 6 February 1942 | Sunk by north of Rabaul at 6.5°N 152°W on 17 May 1942. | ||
| 142 | Yokosuka Naval Arsenal | 20 September 1939 | 29 September 1940 | 27 February 1942 | Sunk by south of Sabtang Island at 20.1667°N 171°W on 26 July 1944. | ||
| 143 | Kure Naval Arsenal | 7 June 1939 | 17 September 1940 | 28 February 1942 | Sunk by a British mine at Singapore on 13 October 1942. Raised and scrapped between August 1959 and February 1960. | ||
| 144 | Yokosuka Naval Arsenal | 6 December 1939 | 13 March 1941 | 30 May 1942 | Sunk by at Attu Island on 13 May 1943. | ||
| 145 | Sasebo Naval Arsenal | 20 January 1940 | 17 December 1940 | 26 April 1942 | Sunk by and USS PC-1135 northeast of Wotje Atoll on 24 March 1943. | ||
| 146 | Mitsubishi, Kōbe Shipyard | 21 February 1940 | 1 May 1941 | 10 June 1942 | Lost in an accident at Truk on 26 September 1942. Salvaged and repaired starting 29 December 1943. Later, lost in another accident at Iyo Nada on 13 June 1944. Salvaged and scrapped starting 28 June 1953. | ||
| 147 | Sasebo Naval Arsenal | 9 January 1941 | 24 September 1941 | 31 August 1942 | Sunk by at Penang Island on 13 November 1943. Salvaged on 4 December 1962. | ||
| 148 | Mitsubishi, Kōbe Shipyard | 2 September 1940 | 24 September 1941 | 31 August 1942 | Sunk by and south of Tarawa on 22 November 1943. | ||
| 149 | Yokosuka Naval Arsenal | 4 December 1940 | 1 November 1941 | 30 September 1942 | Converted to a Kaiten mother ship on 1 September 1944. Decommissioned on 30 November 1945, blown up (along with Ha-106) off the Gotō Islands on 1 April 1946 as part of Operation Road's End. | ||
| 150 | Kure Naval Arsenal | 7 December 1940 | 22 October 1941 | 10 March 1943 | Converted to a Kaiten mother ship on 9 September 1944. Sunk by and north of Palau, on 19 November 1944. | ||
| 151 | Sasebo Naval Arsenal | 19 June 1941 | 15 April 1942 | 31 January 1943 | Sunk by east of Luzon on 13 November 1944. | ||
| 152 | Sasebo Naval Arsenal | 19 June 1941 | 15 April 1942 | 22 April 1943 | Sunk by west of Makin at 3.1667°N 226°W on 16 November 1943. | ||
| 153 | The dummy for the naval budget of the Yamato-class battleships |
Project number S37B. Six boats were planned under the Maru Kyū Programme (Boats 370 - 375), all boats were completed. On the outside this class looked the same as the I-15 class; however, they were built from high-tensile strength steel and equipped with diesel engines of a simpler design.
| +Boats in class | |||||||
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Fate | |
|---|---|---|---|---|---|---|---|
| 370 | Kure Naval Arsenal | 18 March 1942 | 10 November 1942 | 31 July 1943 | Missing after 22 November 1943. | ||
| 371 | Kure Naval Arsenal | 18 March 1942 | 10 November 1942 | 18 September 1943 | Sunk by east of the Philippines at 12.7333°N 172°W on 18 November 1944. | ||
| 372 | Kure Naval Arsenal | 18 March 1942 | 10 November 1942 | 3 November 1943 | Sunk by southwest of Palau at 6.6667°N 137°W on 23 March 1944. | ||
| 373 | Sasebo Naval Arsenal | 27 April 1942 | 25 October 1942 | 5 November 1943 | After completion, converted to a carrier for a Daihatsu-class landing barge. Sunk by north of Truk at 12.7°N 166°W on 15 February 1944. | ||
| 374 | Yokosuka Naval Arsenal | 11 June 1942 | 5 March 1943 | 31 January 1944 | Converted to a Kaiten mother ship on 22 October 1944. Sunk by an aircraft from southeast of Okinawa at 24.25°N 147°W on 29 April 1945. | ||
| 375 | Sasebo Naval Arsenal | 15 July 1942 | 6 March 1943 | 28 December 1943 | Sunk by east of the Philippines on 29 October 1944. |
Project number S37C. Twenty-one boats were planned under the Maru Kyū Programme (Boats 627 - 636) and Kai-Maru 5 Programme (Boats 5101 - 5114). Eighteen boats were cancelled in late 1943, because the IJN was setting the as 1945's main submarines.
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| 627 | Yokosuka Naval Arsenal | 1 July 1942 | 4 May 1943 | 31 March 1944 | Damaged on 25-10-1944 (?)[2] | Sunk east of Leyte by and on 28 October 1944. | |
| 629 | Yokosuka Naval Arsenal | 29 September 1942 | 30 June 1943 | 8 June 1944 | Damaged USS LST-695 on 24 October 1944. Damaged on 25 October 1944 (?). | Conversion to a Kaiten mother ship began in early October 1943 and completed in November 1944. Sunk by,,, and aircraft from east of Okinawa at 26.7°N 168°W on 18 April 1945. | |
| 631 | Yokosuka Naval Arsenal | 26 December 1942 | 9 October 1943 | 7 September 1944 | Sank SS Wild Hunter on 28 July 1945, possibly by Kaiten Sank on 30 July 1945 Damaged on 12 August 1945 by Kaiten (?) | Converted to a Kaiten mother ship before completion. Decommissioned on 30 November 1945, scuttled off the Gotō Islands on 1 April 1946 as part of Operation Road's End. Wreck found in 2017. | |
| 633 - 636 | Cancelled in 1943 | ||||||
| 5101 - 5114 |
Project number S49A. Eighteen boats were planned under the Kai-Maru 5 Programme (Boats 5115 - 5132). However, all boats were cancelled in late 1943, because the IJN concentrated on production of from 1945.
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Fate | |
| 5115 - 5132 | Cancelled in 1943 |
| Type | Type-B (I-15) | Type-B Mod. 1 (I-40) | Type-B Mod. 2 (I-54) | V22A Type | ||
| Displacement | Surfaced | 2198LT | 2230LT | 2140LT | 2330LT | |
| Submerged | 3654LT | 3700LT | 3688LT | No data | ||
| Length (overall) | 108.7m (356.6feet) | 108.7m (356.6feet) | 108.7m (356.6feet) | 106.5m (349.4feet) (waterline) | ||
| Beam | 9.3m (30.5feet) | 9.3m (30.5feet) | 9.3m (30.5feet) | 9.64m (31.63feet) | ||
| Draft | 5.14m (16.86feet) | 5.2m (17.1feet) | 5.19m (17.03feet) | 5.32m (17.45feet) | ||
| Depth | 7.9m (25.9feet) | 7.9m (25.9feet) | 7.9m (25.9feet) | No data | ||
| Power plant and shaft | 2 × Kampon Mk. 2 Model 10 diesels 2 shafts | 2 × Kampon Mk. 1A Model 10 diesels 2 shafts | 2 × Kampon Mk. 22 Model 10 diesels 2 shafts | 2 × Kampon Mk. 2 Model 10 diesels 2 shafts | ||
| Power | Surfaced | 12,400 bhp | 11,000 bhp | 4,700 bhp | 11,000 bhp | |
| Submerged | 2,000 shp | 2,000 shp | 1,200 shp | 2,400 shp | ||
| Speed | Surfaced | 23.6kn | 23.5kn | 17.7kn | 22.4kn | |
| Submerged | 8kn | 8kn | 6.5kn | 8kn | ||
| Range | Surfaced | 14000abbr=onNaNabbr=on at 16kn | 14000abbr=onNaNabbr=on at 16kn | 21000abbr=onNaNabbr=on at 16kn | 14000abbr=onNaNabbr=on at 16kn | |
| Submerged | 96abbr=onNaNabbr=on at 3kn | 96abbr=onNaNabbr=on at 3kn | 105abbr=onNaNabbr=on at 3kn | 80abbr=onNaNabbr=on at 3kn | ||
| Test depth | 100m (300feet) | 100m (300feet) | 100m (300feet) | 100m (300feet) | ||
| Fuel | 774 tons | 814 tons | 842.8 tons | 735 tons | ||
| Complement | 94 | 94 | 94 | No data | ||
| Armament (initial) | • 6 × 5330NaN0 Torpedo tubes (6 × front) • 17 × Type 95 torpedoes • 1 × 140mm L/40 11th Year Type naval gun[3] • 2 × Type 96 25mm AA guns | • 6 × 5330NaN0 TTs (6 × front) • 17 × Type 95 torpedoes • 1 × 140mm L/40 11th Year Type Naval gun • 2 × Type 96 25mm AA guns | • 6 × 5330NaN0 TTs (6 × front) • 19 × Type 95 torpedoes • 1 × 140mm L/40 11th Year Type Naval gun • 2 × Type 96 25mm AA guns | • 8 × 5330NaN0 TTs (8 × front) • 16 × torpedoes • 1 × 14 cm/40 11th Year Type naval gun • 4 × 25mm AA guns • 8 × naval mines | ||
| Aircraft and facilities | • Catapult and hangar • 1 × Watanabe E9W1 Slim seaplane | • Catapult and hangar • 1 × Yokosuka E14Y2 Glen seaplane | • Catapult and hangar • 1 × Yokosuka E14Y2 Glen seaplane | • Catapult and hangar • 1 × floatplane | ||