# Type A submarine

The Cruiser submarine Type-A (巡潜甲型潜水艦, Junsen Kō-gata sensuikan) was a class of submarine in the Imperial Japanese Navy (IJN), which served during the Second World War. The Type-A submarines were built to take a role of the command ships for submarine squadrons. For this reason they had equipment for a headquarters, better radio facilities and a floatplane.

## Class variants

The Type-A submarines were divided into four classes:
* Type-A (甲型（伊九型）, Kō-gata, I-9-class)
* Type-A Mod.1 (甲型改一（伊十二型）, Kō-gata Kai-1, I-12-class)
* Type-A Mod.2 (甲型改二（伊十三型）, Kō-gata Kai-2, I-13-class)
* V21 Type (第5094号艦型, Dai-5094-Gō kan-gata, 5094th vessel-class). The 5094th vessel class boats were not built and remained only a design.

### Type-A (I-9 class)

Project number S35Ja. Their design was based on the Junsen III (I-7 class). Three boats were built in 1938-42 under the Maru 3 Programme (Boat # 35 - 36) and Maru 4 Programme (Boat # 138).
* Boats in class
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| 35 | I-9 | Kure Naval Arsenal | 25-01-1938 | 20-05-1939 | 13-02-1941 | Sank USS Lahaina 12-12-1941 | Sunk by USS Frazier at Kiska 52°08′N 177°38′E﻿ / ﻿52.133°N 177.633°E﻿ / 52.133; 177.633﻿ (I-9) 13-06-1943. |
| 36 | I-10 | Kawasaki-Kōbe Shipyard | 07-06-1938 | 20-09-1939 | 31-10-1941 | Sank Panamanian merchant ship Donerail 10-12-1941 Sank USS Melvin H. Baker 05-06-1942 Sank Panamanian merchant ship Atlantic Gulf 06-06-1942 Sank RMS King Lud 08-06-1942 Sank RMS Queen Victoria 28-06-1942 Sank USS Express 30-06-1942 Sank Greek merchantman Nymphe 06-07-1942 Sank RMS Hartismere 08-07-1942 Sank Dutch merchant ship Alchiba 09-07-1942 Sank USS Samuel Gompers 30-01-1943 Sank USS Gulfwave 01-03-1943 Sank Norwegian merchantman Alcides 22-07-1943 Sank Norwegian merchant ship Bramora 14-09-1943 Sank USS Elias Howe 24-09-1943 Sank Norwegian merchant ship Storvixen 01-10-1943 Sank Norwegian merchantman Anna Knudsen 02-10-1943 Sank RMS Congella 24-10-1943 Sank or damaged unknown warship 02-07-1944 | Sunk by USS David W. Taylor and USS Riddle east of Saipan 15°26′N 147°48′E﻿ / ﻿15.433°N 147.800°E﻿ / 15.433; 147.800﻿ (I-10) 04-07-1944. |
| 138 | I-11 | Kawasaki-Kōbe Shipyard | 10-04-1940 | 28-02-1941 | 16-05-1942 | Sank Greek merchant ship George S. Livanos 20-07-1942 Sank USS Coast Farmer 21-07-1942 Sank USS William Dawes 22-07-1942 Damaged HMAS Hobart 20-07-1943 Damaged USS Matthew Lyon 11-08-1943 | Lost in an accident or sunk by a mine near Funafuti January 1944. |

### Type-A Mod.1 (I-12 class)

Project number S35B. Five boats were planned under the Maru Tsui Programme (Boat # 620 - 621) and the Kai-Maru 5 Programme (Boat # 5091 - 5093). They were equipped with less powerful diesel engines which shortened the time needed to build them. Only one boat, I-12, was completed to the original design. The I-13 and the later boats were converted to a new submarine class (I-13 class), because the number of I-400 class boats was reduced.
* Boats in class
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| 620 | I-12 | Kawasaki-Kōbe Shipyard | 05-11-1942 | 03-08-1943 | 25-05-1944 | Sank USS John A. Johnson 30-10-1944 | Sunk by minesweeper USS Ardent on 13-11-1944. |
| 621 | I-13 | Kawasaki-Kōbe Shipyard | 04-02-1943 | | | | Converted to the I-13 class in October 1943. |
| 5091 | I-14 | Kawasaki-Kōbe Shipyard | 18-05-1943 | | | | Converted to the I-13 class in October 1943. |
| 5092 | I-15 | Kawasaki-Senshū Shipyard | 30-04-1943 | | | | Converted to the I-13 class in October 1943. |
| 5093 | I-1 | Kawasaki-Senshū Shipyard | 24-06-1943 | | | | Converted to the I-13 class in October 1943. |

### Type-A Mod.2 (I-13 class)

Project number S35C. Four boats were planned under the Maru Tsui Programme (Boat # 621) and the Kai-Maru 5 Programme (Boat # 5091 - 5093). However, four boats were converted to new submarine class (I-13 class), because a number of submarines of the I-400 class were cancelled. They had a large hangar and were equipped with bulges to be able to operate 2 × special Aichi M6A1 Seiran attack bombers. The headquarters institutions were removed.
* Boats in class
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Fate |
| 621 | I-13 | Kawasaki-Kōbe Shipyard | 04-02-1943 | 30-11-1943 | 16-12-1944 | Sunk by USS Lawrence C. Taylor, USS Robert F. Keller and aircraft from USS Anzio northeast of the Ogasawara Islands 16-07-1945. |
| 5091 | I-14 | Kawasaki-Kōbe Shipyard | 18-05-1943 | 14-03-1944 | 14-03-1945 | Captured by USS Murray 27-08-1945, decommissioned 15-09-1945, sunk as a target off the Hawaiian Islands 28-05-1946. |
| 5092 | I-15 | Kawasaki-Senshū Shipyard Kawasaki-Kōbe Shipyard (after launch) | 30-04-1943 | 12-04-1944 | | Converted to a tanker submarine in June 1945; 90% complete; scrapped in 1945. |
| 5093 | I-1 | Kawasaki-Kōbe Shipyard Kawasaki-Senshū Shipyard (after launch) | 24-06-1943 | 10-06-1944 | | 70% complete; Sunk by a typhoon on 18-09-1945; later salvaged and scrapped. |

### V21 Type

Project number S48. Three boats were planned under the Kai-Maru 5 Programme. However, all boats were cancelled in late 1943, because the IJN turned its attention to the construction of Type E submarine [ja] (戊型潜水艦, Bo-gata sensuikan) in 1945.
* Boats in class
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Fate |
| 5094 - 5096 | | | | | | Cancelled in 1943. |

## Characteristics

| Type | Type | Type-A (I-9) | Type-A Mod.1 (I-12) | Type-A Mod.2 (I-13) | V21 Type |
| Displacement | Surfaced | 2,434 long tons (2,473 t) | 2,390 long tons (2,428 t) | 2,620 long tons (2,662 t) | 2,330 long tons (2,367 t) |
| Displacement | Submerged | 4,150 long tons (4,217 t) | 4,172 long tons (4,239 t) | 4,762 long tons (4,838 t) | No data |
| Length (overall) | Length (overall) | 113.70 m (373 ft 0 in) | 113.70 m (373 ft 0 in) | 113.70 m (373 ft 0 in) | 111.00 m (364 ft 2 in) (waterline) |
| Beam | Beam | 9.55 m (31 ft 4 in) | 9.55 m (31 ft 4 in) | 11.70 m (38 ft 5 in) | 9.82 m (32 ft 3 in) |
| Draft | Draft | 5.36 m (17 ft 7 in) | 5.36 m (17 ft 7 in) | 5.89 m (19 ft 4 in) | 5.50 m (18 ft 1 in) |
| Depth | Depth | 8.30 m (27 ft 3 in) | 8.30 m (27 ft 3 in) | 8.30 m (27 ft 3 in) | No data |
| Power plant and shaft | Power plant and shaft | 2 × Kampon Mk.2 Model 10 diesels 2 shafts | 2 × Kampon Mk.22 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 | 4,700 bhp | 4,700 bhp | 11,000 bhp |
| Power | Submerged | 2,400 shp | 1,200 shp | 600 shp | 2,400 shp |
| Speed | Surfaced | 23.5 knots (43.5 km/h) | 17.7 knots (32.8 km/h) | 16.7 knots (30.9 km/h) | 22.4 knots (41.5 km/h) |
| Speed | Submerged | 8.0 knots (14.8 km/h) | 6.2 knots (11.5 km/h) | 5.5 knots (10.2 km/h) | 8.0 knots (14.8 km/h) |
| Range | Surfaced | 16,000 nmi (30,000 km) at 16 knots (30 km/h) | 22,000 nmi (41,000 km) at 16 knots (30 km/h) | 21,000 nmi (39,000 km) at 16 knots (30 km/h) | 16,000 nmi (30,000 km) at 16 knots (30 km/h) |
| Range | Submerged | 90 nmi (170 km) at 3 knots (5.6 km/h) | 75 nmi (139 km) at 3 knots (5.6 km/h) | 60 nmi (110 km) at 3 knots (5.6 km/h) | 80 nmi (150 km) at 3 knots (5.6 km/h) |
| Test depth | Test depth | 100 m (330 ft) | 100 m (330 ft) | 100 m (330 ft) | 100 m (330 ft) |
| Fuel | Fuel | 878 tons | 917 tons | 917 tons | 880 tons |
| Complement | Complement | 104 | 112 | 108 | No data |
| Armament (initial) | Armament (initial) | • 6 × 533 mm (21 in) Torpedo tubes (6 × front) • 18 × Type 95 torpedoes • 1 × 140 mm (5.5 in) L/40 11th Year Type Naval gun • 4 × Type 96 25mm AA guns | • 6 × 533 mm (21 in) TTs (6 × front) • 18 × Type 95 torpedoes • 1 × 140 mm (5.5 in) L/40 11th Year Type Naval gun • 4 × Type 96 25mm AA guns | • 6 × 533 mm (21 in) TTs (6 × front) • 12 × Type 95 torpedoes • 1 × 140 mm (5.5 in) L/40 11th Year Type Naval gun • 10 × Type 96 25mm AA guns | • 6 × 533 mm (21 in) TTs (6 × front) • 18 × torpedoes • 1 × 140 mm Naval gun • 4 × 25mm AA guns |
| Aircraft and facilities | Aircraft and facilities | • Catapult and hangar • 1 × Watanabe E9W1 Slim seaplane | • Catapult and hangar • 1 × Yokosuka E14Y2 Glen seaplane | • Catapult and hangar • 2 × Aichi M6A1 Seiran floatplane | • Catapult and hangar • 1 × floatplane |

## Footnotes

* ↑ 伊号第9潜水艦 (I-Gō Dai-9 Sensuikan). The same shall apply hereinafter.
* ↑ Senshi Sōsho Vol.88 (1975), p.272
* 1 2 3 Campbell, John Naval Weapons of World War Two ISBN 0-87021-459-4 p.191