Type B submarine

Class overview
Name:	Type-B submarines • Type-B (I-15 class) • Type-B Modified 1 (I-40 class) • Type-B Modified 2 (I-54 class)
Builders:	Kure Naval Arsenal Sasebo Naval Arsenal Yokosuka Naval Arsenal Kawasaki Shipbuilding Mitsubishi Heavy Industries
Operators:	Imperial Japanese Navy
Built:	1938-1944
In commission:	1940-1945

The Cruiser submarine Type-B (巡潜乙型, Junsen Otsu-gata^?) 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.

1 Class variants
2 Characteristics
3 Footnotes
4 Bibliography

Class variants

The Type-B submarines were divided into four classes:

Type-B (乙型, Otsu-gata^?), the I-15 class
Type-B Mod.1 (乙型改一, Otsu-gata Kai-1^?), the I-40 class
Type-B Mod.2 (乙型改二, Otsu-gata Kai-2^?), the I-54 class
V22A Type (第5115号艦型, 5115th vessel class^?). The 5115th vessel class submarines were not built and remained a design only.

Type-B (I-15 class)

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	Results	Fate
37	I-15 ^[1]	Kure Naval Arsenal	25-01-1938	07-03-1939	30-09-1940		Probably lost in an accident or sunk by enemy attack near Guadalcanal, after 03-11-1942
38	I-17	Yokosuka Naval Arsenal	25-08-1937	12-11-1938	31-01-1941	Sank SS Samoa on 18-12-1941 Sank SS Emidio on 21-12-1941 Damaged SS Larry Doheny on 23-12-1941 Sank Panamanian merchant ship Stanvac Manila on 23-05-1943	Sunk by HMNZS Tui and maritime patrol aircraft at Nouméa on 19-08-1943
39	I-19	Mitsubishi, Kōbe Shipyard	15-03-1938	16-09-1939	28-04-1941	Sank SS H. M. Storey on 22-12-1941 Damaged SS Absoroka on 25-12-1941 Sank USS Wasp on 15-09-1942 Damaged USS North Carolina on 15-09-1942 Damaged USS O'Brien on 15-09-1942 Sank SS Phoebe A. Hearst on 30-04-1943 Damaged SS William Williams on 02-05-1943 Sank SS William K. Vanderbilt on 16-05-1943 Sank SS M. H. DeYoung on 14-08-1943	Sunk by USS Radford in the Gilbert Islands on 25-11-1943
40	I-21	Kawasaki, Kōbe Shipyard	07-01-1939	24-02-1940	15-07-1941	Damaged SS Montebello on 23-12-1941 Damaged SS Idaho on 23-12-1941 Sank SS John Adams on 05-05-1942 Sank Greek merchant vessel Chloe on 04-05-1942 Sank Panamanian merchantman Guatemala on 11-06-1942 Sank USS Porter on 26-10-1942 Damaged SS Edgar Allan Poe on 08-11-1942 Sank Australian merchant ship Kalingo on 17-01-1943 Sank SS Peter H. Burnett on 22-01-1943 Sank RMS Iron Knight on 08-02-1943 Sank SS Star King on 10-02-1943 Sank SS Cape San Juan on 21-11-1943	Probably lost in an accident or sunk by enemy attack near Tarawa, after 27-11-1943
41	I-23	Yokosuka Naval Arsenal	08-12-1938	24-11-1939	27-09-1941	Damaged SS Agwiworld on 21-12-1941 Damaged SS Dorothy Philips on 24-12-1941	Probably lost in an accident or sunk by enemy attack near the Hawaiian Islands, after 14-02-1942
42	I-25	Mitsubishi, Kōbe Shipyard	03-02-1939	08-06-1940	15-10-1941	Sank USS Emidio on 20-12-1941 Damaged SS Absaroka on 24-12-1941 Damaged SS Connecticut on 27-12-1941 Sank RMS Fort Camosun on 21-06-1942 Sank Camden on 04-10-1942 Sank Larry Doheny on 07-10-1942 Sank Soviet submarine L16 on 12-10-1942 Sank SS H. M. Storey on 18-05-1943	Probably lost in an accident or sunk by enemy attack near Espiritu Santo, after 23-08-1943
43							The dummy for the naval budget of the Yamato class battleships.
139	I-26	Kure Naval Arsenal	07-06-1939	10-04-1940	06-11-1941	Sank USS Cynthia Olson on 08-12-1941 Sank SS Coast Trader on 08-06-1942 Damaged USS Saratoga on 31-08-1942 Sank USS Juneau on 13-11-1942 Sank Yugoslav merchant ship Recina on 11-04-1943 Sank Australian merchant vessel Kowarra on 24-04-1943 Damaged SS General Robert F. Hoke on 28-12-1943 Sank RMS Tornus on 31-12-1943 Sank SS Albert Gallatin on 01-01-1944 Sank SS H. D. Collier on 13-03-1944 Sank Norwegian merchant ship Grena on 21-03-1944 Damaged USS Santee on 25-10-1944 (probably wrong since she was sunk the day before)^[2] Sank SS Richard Hovey on 29-03-1944	Probably lost in an accident or sunk by enemy attack east of the Philippines, after 27-10-1944
140	I-27	Sasebo Naval Arsenal	05-07-1939	06-06-1940	24-02-1942	Sank Australian merchant ship Iron Crown on 04-05-1942 Sank RMS Ocean Vintage on 10-22-1942 Sank RMS Fort Mumford on 21-03-1943 Sank Dutch merchantman Berakit on 07-05-1943 Sank SS Montanan on 03-06-1943 Sank RMS British Venture on 24-06-1943 Sank Norwegian merchant ship Dah Pu on 28-06-1943 Sank SS Alcoa Prospector on 05-07-1943 Damaged SS Lyman Stewart on 07-09-1943 Sank RMS Larchbank on 10-09-1943 Sank RMS Sambo on 10-11-1943 Sank RMS Sambridge on 18-11-1943 Sank Greek merchant ship Athina Livanos on 29-11-1943 Sank Greek merchant vessel Nitsa on 02-12-1943 Damaged RMS Fort Camosun on 03-12-1943 Sank HMS Khedive Ismail on 12-02-1944	Sunk by HMS Paladin and HMS Petard in the Maldives at on 12-02-1944
141	I-28	Mitsubishi, Kōbe Shipyard	25-09-1939	17-12-1940	06-02-1942		Sunk by USS Tautog north of Rabaul at on 17-05-1942
142	I-29	Yokosuka Naval Arsenal	20-09-1939	29-09-1940	27-02-1942	Sank RMS Gazcon on 02-09-1942 Damaged RMS British Genius on 03-09-1942 Sank RMS Haresfield on 10-09-1942 Sank RMS Ocean Honour on 16-09-1942 Sank USS Paul Luckenbach on 23-09-1942 Sank RMS Tilawa on 23-11-1942 Sank Norwegian merchant ship Belita on 03-12-1942 Sank RMS Rahmani on 12-07-1943	Sunk by USS Sawfish south of Sabtang Island at on 26-07-1944
143	I-30	Kure Naval Arsenal	07-06-1939	17-09-1940	28-02-1942		Sunk by a mine at Singapore on 13-10-1942
144	I-31	Yokosuka Naval Arsenal	06-12-1939	13-03-1941	30-05-1942		Sunk by USS Farragut and USS Edwards at Attu Island on 14-05-1943
145	I-32	Sasebo Naval Arsenal	20-01-1940	17-12-1940	26-04-1942		Sunk by USS Manlove and USS PT-1135 northeast of Wotje Atoll on 24-03-1943
146	I-33	Mitsubishi, Kōbe Shipyard	01-02-1940	01-05-1941	10-06-1942		Lost in an accident at Truk on 26-09-1942. Salvaged and repaired starting 29-12-1942. Later, lost in another accident at Iyo Nada on 13-06-1944. Salvaged and scrapped starting 28-06-1953
147	I-34	Sasebo Naval Arsenal	09-01-1941	24-09-1941	31-08-1942		Sunk by HMS Taurus at Penang Island on 13-11-1943
148	I-35	Mitsubishi, Kōbe Shipyard	02-09-1940	24-09-1941	31-08-1942		Sunk by USS Meade and USS Frazier south of Tarawa on 22-11-1943
149	I-36	Yokosuka Naval Arsenal	04-12-1940	01-11-1941	30-09-1942	Damaged USS Mazama on 09-01-1945 by Kaiten Damaged USS LCI(L)-600 on 09-01-1945 by Kaiten Damaged USS Endymion on 22-06-1945 Damaged USS LST-513 on 22-06-1945 (?)	Converted to the Kaiten mother ship on 01-09-1944. Decommissioned on 30-11-1945, sunk as a target off Gotō Islands on 01-04-1946
150	I-37	Kure Naval Arsenal	07-12-1940	22-10-1941	10-03-1943	Sank RMS San Ernesto on 16-03-1943 Sank SS Henry Knox on 19-03-1943 Sank Greek merchant ship Faneromeni on 23-10-1943 Sank Norwegian merchant vessl Scotia on 27-11-1943 Sank RMS British Chivalry on 22-02-1944 Sank RMS Sutlej on 26-02-1944 Sank RMS Ascot on 29-02-1944	Converted to the Kaiten mother ship on 09-09-1944. Sunk by USS Conklin and USS McCoy Reynolds north of Palau, on 19-11-1944
151	I-38	Sasebo Naval Arsenal	19-06-1941	15-04-1942	31-01-1943		Sunk by USS Nicholas east of Luzon on 12-11-1944
152	I-39	Sasebo Naval Arsenal	19-06-1941	15-04-1942	22-04-1943	Sank USS Navajo on 12-09-1943	Sunk by USS Boyd west of Makin at on 16-11-1943
153							The dummy for the naval budget of the Yamato class battleships

Type-B Mod.1 (I-40 class)

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	Results	Fate
370	I-40	Kure Naval Arsenal	18-03-1942	10-11-1942	31-07-1943		Probably lost in an accident, after 22-11-1943
371	I-41	Kure Naval Arsenal	18-03-1942	10-11-1942	18-09-1943	Damaged by USS Reno on 03-11-1944	Sunk by USS Lawrence C. Taylor east of the Philippines at on 12-11-1944
372	I-42	Kure Naval Arsenal	18-03-1942	10-11-1942	03-11-1943		Sunk by USS Tunny southwest of Palau at on 23-03-1944
373	I-43	Sasebo Naval Arsenal	27-04-1942	10-25-1942	05-11-1943		Sunk by USS Aspro north of Truk at on 15-02-1944
374	I-44	Yokosuka Naval Arsenal	11-06-1942	05-03-1943	31-01-1944	Possibly sank USS Snook on 17-04-1945 (?)	Converted to the Kaiten mother ship on 22-10-1944. Sunk by USS Heermann, USS Uhlmann, USS Mertz, USS Collett and aircraft from USS Bataan north-northwest of Minami Daitō at on 18-04-1945
375	I-45	Sasebo Naval Arsenal	15-07-1942	06-03-1943	28-12-1943	Damaged USS Santee on 25-10-1944 (?)^[2] Sank USS Eversole on 28-10-1944	(1). Sunk by USS Gridley and USS Helm east of the Philippines at on 28-10-1944. (2). Sunk by USS Whitehurst east of the Philippines on 28-10-1944

Type-B Mod.2 (I-54 class)

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 Type-E submarine (戊型潜水艦, Bo-gata sensuikan^?) as 1945's main submarines

Boats in class

Boat No.	Boat	Builder	Laid down	Launched	Completed	Results	Fate
627	I-54	Yokosuka Naval Arsenal	01-07-1942	04-05-1943	31-03-1944	Damaged USS Santee on 25-10-1944 (?)^[2]	(1). Sunk by USS Gridley and USS Helm east of the Philippines at on 28-10-1944 (2). Sunk by USS Whitehurst east of the Philippines on 28-10-1944
629	I-56	Yokosuka Naval Arsenal	29-09-1942	30-06-1943	08-06-1944	Damaged USS LST-695 on 24-10-1944 Damaged USS Santee on 25-10-1944 (?)^[2]	Converted to the Kaiten mother ship on 14-11-1944. Sunk by USS Hudson at Kumejima Island, at on 05-04-1945
631	I-58	Yokosuka Naval Arsenal	26-12-1942	09-10-1943	07-09-1944	Damaged USS Lowry on 28-07-1945 by Kaiten Sank USS Indianapolis on 30-07-1945 Damaged USS Thomas F. Nickel on 12-08-1945 by Kaiten (?)	Converted to the Kaiten mother ship, before completion. Decommissioned on 30-11-1945, sunk as a target off the Gotō Islands on 01-04-1946
633 - 636							Cancelled in 1943
5101 - 5114							Cancelled in 1943

V22A Type

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 Type-E submarine (戊型潜水艦, Bo-gata sensuikan^?) from 1945 onwards

Boats in class

Boat No.	Boat	Builder	Laid down	Launched	Completed	Fate
5115 - 5132						Cancelled in 1943

Characteristics

Type		Type-B (I-15)	Type-B Mod. 1 (I-40)	Type-B Mod. 2 (I-54)	V22A Type
Displacement	Surfaced	2,198 long tons (2,233 t)	2,230 long tons (2,266 t)	2,140 long tons (2,174 t)	2,330 long tons (2,367 t)
Displacement	Submerged	3,654 long tons (3,713 t)	3,700 long tons (3,759 t)	3,688 long tons (3,747 t)	No data
Length (overall)		108.70 m (356 ft 8 in)	108.70 m (356 ft 8 in)	108.70 m (356 ft 8 in)	106.50 m (349 ft 5 in) (waterline)
Beam		9.30 m (30 ft 6 in)	9.30 m (30 ft 6 in)	9.30 m (30 ft 6 in)	9.64 m (31 ft 8 in)
Draft		5.14 m (16 ft 10 in)	5.20 m (17 ft 1 in)	5.19 m (17 ft 0 in)	5.32 m (17 ft 5 in)
Depth		7.90 m (25 ft 11 in)	7.90 m (25 ft 11 in)	7.90 m (25 ft 11 in)	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
Power	Submerged	2,000 shp	2,000 shp	1,200 shp	2,400 shp
Speed	Surfaced	23.6 knots (43.7 km/h)	23.5 knots (43.5 km/h)	17.7 knots (32.8 km/h)	22.4 knots (41.5 km/h)
Speed	Submerged	8.0 knots (14.8 km/h)	8.0 knots (14.8 km/h)	6.5 knots (12.0 km/h)	8.0 knots (14.8 km/h)
Range	Surfaced	14,000 nmi (26,000 km) at 16 knots (30 km/h)	14,000 nmi (26,000 km) at 16 knots (30 km/h)	21,000 nmi (39,000 km) at 16 knots (30 km/h)	14,000 nmi (26,000 km) at 16 knots (30 km/h)
Range	Submerged	96 nmi (178 km) at 3 knots (5.6 km/h)	96 nmi (178 km) at 3 knots (5.6 km/h)	105 nmi (194 km) at 3 knots (5.6 km/h)	80 nmi (150 km) at 3 knots (5.6 km/h)
Test depth		100 m (330 ft)	100 m (330 ft)	100 m (330 ft)	100 m (330 ft)
Fuel		774 tons	814 tons	842.8 tons	735 tons
Complement		94	94	94	No data
Armament (initial)		• 6 × 533 mm (21 in) Torpedo tubes (6 × front) • 17 × Type 95 torpedoes • 1 × 140 mm (5.5 in) L/40 11th Year Type Naval gun • 2 × Type 96 25mm AA guns	• 6 × 533 mm (21 in) TTs (6 × front) • 17 × Type 95 torpedoes • 1 × 140 mm (5.5 in) L/40 11th Year Type Naval gun • 2 × Type 96 25mm AA guns	• 6 × 533 mm (21 in) TTs (6 × front) • 19 × Type 95 torpedoes • 1 × 140 mm (5.5 in) L/40 11th Year Type Naval gun • 2 × Type 96 25mm AA guns	• 8 × 533 mm (21 in) TTs (8 × front) • 16 × torpedoes • 1 × 140 mm 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

Footnotes

^ 伊号第15潜水艦 (I-Gō Dai-15 Sensuikan^?). The same shall apply hereinafter.
^ ^a ^b ^c ^d This result is estimated with a thing by I-56 in many Japanese documents. However, her actions cannot prove it.

Bibliography

"Rekishi Gunzō". http://rekigun.net/. , History of Pacific War Vol.17 I-Gō Submarines, Gakken (Japan), January 1998, ISBN 4-05-601767-0
Rekishi Gunzō, History of Pacific War Vol.35 Kō-hyōteki and Kōryū, Gakken (Japan), April 2002, ISBN 4-05-602741-2
Rekishi Gunzō, History of Pacific War Vol.36 Kairyū and Kaiten, Gakken (Japan), May 2002, ISBN 4-05-602693-9
Rekishi Gunzō, History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces", Gakken (Japan), March 2005, ISBN 4-05-603890-2
Model Art Extra No.537, Drawings of Imperial Japanese Naval Vessels Part-3, Model Art Co. Ltd. (Japan), May 1999, Book code 08734-5
The Maru Special, Japanese Naval Vessels No.31 Japanese Submarines I, Ushio Shobō (Japan), September 1979, Book code 68343-31

Type B submarine

Type B1	I-15 · I-17 · I-19 · I-21 · I-23 · I-25 · I-26 · I-27 · I-28 · I-29 · I-30 · I-31 · I-32 · I-33 · I-34 · I-35 · I-36 · I-37 · I-38 · I-39

Type B2	I-40 · I-41 · I-42 · I-43 · I-44 · I-45

Type B3	I-54 · I-56 · I-58

Imperial Japanese Navy submarines

Japanese naval ship classes of World War II

Aircraft carriers	Hōshō^S Akagi^SC Kaga^SC Ryūjō^S Sōryū^S Hiryū^S Shōkaku Hiyō^C Taihō^S Unryū Shinano^SC

Light aircraft carriers	Zuihō^C Ryūhō^SC Chitose^C Ibuki^SCI

Escort carriers	Navy: Taiyō^C Kaiyo^SC Shinyo^SC Shimane Maru^C Army: Akitsu Maru^C Yamashio Maru^C Kumano Maru^SC

Battleships	Kongō Fusō Ise Nagato Yamato

Heavy cruisers	Furutaka Aoba Myōkō Takao Mogami^L Tone Yakumo (Reclassified)^S Izumo (Reclassified)

Light cruisers	Tenryū Kuma Nagara Yūbari^S Sendai Katori Agano Ōyodo^S

Destroyers	1st class: Minekaze Kamikaze Mutsuki Fubuki Akatsuki Hatsuharu Shiratsuyu Asashio Kagerō Yūgumo Akizuki Shimakaze^S Matsu Tachibana 2nd class: Momi Wakatake

Torpedo boats	Chidori Ōtori

Submarines	1st class: Junsen Type A (Kō) Type B (Otsu) Type C (Hei) Type D (Tei) Kaidai Kiraisen (I-121) Senho (I-351) Sentoku (I-400) Sentaka (I-201) 2nd class: Kaichū Type L Ko Sen'yu-Ko Sentaka-Ko Army: Maru Yu

Submarine tenders	Jingei

Gunboats	Ocean gunboat: Saga^S Ataka^S Hashidate Okitsu (ex-RN Lepanto)^SC River gunboat: Toba^S Seta Atami Fushimi Kotaka^S Karatsu (ex-USS Luzon)^S Maiko (ex-PN Macau)^S Narumi (ex-RN Ermanno Carlotto)^S Suma (ex-HMS Moth)^S Tatara (ex-USS Wake)^S

Escort ships	Shimushu Etorofu Mikura Hiburi Ukuru No.1 No.2 Ioshima (ex-ROCN Ning Hai class)^C

Small craft	Daihatsu (landing craft) Shinyo (suicide boat) Kaiten (manned torpedo) Ko-hyoteki (midget submarine) Kairyu (midget submarine)

S — Single ship of class C — Converted to ship type L — Officially classed as light cruisers under Washington Naval Treaty until 1939 refits I — Incomplete until the end of the war