Junsen type submarine

The was a ship class of submarines of the Imperial Japanese Navy (IJN). There were four submarine designs of the Junsen type: J1, a modified J1, J2 and the J3.

Class variants

The Junsen type submarines were divided into four classes:

• .

Junsen I (I-1 class)

File:Japanese submarine I-1.jpg

I-1 in 1930

Four boats were built in 1923-1929. Genealogy of the large-size submarine in the IJN began with . Japan received six U-boats from Germany as reparations of World War I. The IJN copied , one of the six, producing the I-21-class minelayer submarine. The IJN could not find an optimal design of fleet submarine, so they and Kawasaki Heavy Industries sent many technical officers to the United Kingdom and Germany and got drawings of advanced submarines. The British L class became the Kaidai I, the K class became the Kaidai II and U-142 become Junsen I.

Boat	Builder	Laid down	Launched	Completed	Results	Fate
	Kawasaki Shipbuilding	12-03-1923	15-10-1924	10-03-1926	Damaged 31-12-1941 Sank Dutch merchant ship Siantar 03-03-1942	Sunk by and at Guadalcanal 29-01-1943.
	Kawasaki Shipbuilding	06-08-1923	23-02-1925	24-07-1926	Sank Dutch merchant ship Parigi 01-03-1942 Sank RMS Chilka 11-03-1942	Sunk by north of Rabaul 07-04-1944.
	Kawasaki Shipbuilding	01-11-1924	08-06-1925	30-11-1926	Sank RMS Elmdale 07-04-1942 Sank RMS Fultala 08-04-1942	Sunk by USS PT-59 at Kamimbo 09-12-1942.
	Kawasaki Shipbuilding	17-04-1926	22-05-1928	24-12-1929	Sank Norwegian merchant ship Hoegh Merchant 14-12-1941 Sank Dutch merchant ship Ban Ho Guan 28-02-1942 Sank USS Washingtonian 06-04-1942 Damaged unknown sailing boat 10-04-1942 Damaged 27-09-1942	Sunk by southeast of Rabaul 20-12-1942.

Junsen I Mod (I-5 class)

File:Japanese submarine I-5 in 1932.jpg

I-5 in 1932

This is a type which added a floatplane to the Junsen I.

Boat	Builder	Laid down	Launched	Completed	Results	Fate
	Kawasaki Shipbuilding	30-10-1929	19-06-1931	31-07-1932		Sunk by east of Saipan 19-07-1944.

Junsen II (I-6 class)

File:Japanese submarine I-6 in 1935.jpg

I-6 in 1935

Project number S32. This is a type which added a catapult to the Junsen I Mod. She was built in 1931 under the 1st Naval Armaments Supplement Programme (Maru 1).

Boat	Builder	Laid down	Launched	Completed	Results	Fate
	Kawasaki-Kōbe Shipyard	14 October 1932	31 March 1934	15 May 1935	Damaged aircraft carrier 11 January 1942 Sank Clan Line cargo ship SS Clan Ross 2 April 1942 Sank RMS Bahadar 7 April 1942 Sank two unknown sailing boats 10 April 1942	Accidentally rammed, attacked and sunk by Toyokawa Maru northeast of Hachijo-Shima on 16 June 1944.

Junsen III (I-7 class)

File:Japanese submarine I-7 in 1937.jpg

I-7 in 1937

Project number S33. These boats combined the good points of the Junsen II and the Kaidai V. They were built in 1934 under the Maru 2 Programme. Junsen III became a 'typeship' for the Type-A, B and C.

Boat	Builder	Laid down	Launched	Completed	Results	Fate
	Kure Naval Arsenal	12 September 1934	3 July 1935	31 March 1937	Sank Dutch merchant ship Le Maire 04-03-1942 Sank RMS Glenshiel 03-04-1942 Sank USS Arcata 15-07-1942	Damaged by at Kiska 21 June 1943. Scuttled 5 July 1943.
	Kawasaki-Kōbe Shipyard	11-10-1934	20-07-1936	05-12-1938	Sank Dutch merchant ship Tjisalak 26-03-1944 Sank RMS City of Adelaide 30-03-1944 Sank Australian merchant ship Nellore 29-06-1944 Sank USS Jean Nicolet 02-07-1944	Sunk by southeast of Okinawa Island 31-03-1945.

Characteristics

Type		Junsen I (I-1)	Junsen I Mod. (I-5)	Junsen II (I-6)	Junsen III (I-7)
Displacement	Surfaced		same as Junsen I
	Submerged
Length (overall)
Beam
Draft
Depth
Power plant and shaft		2 × Rauschenbach Mk.2 diesels 2 shafts		2 × Kampon Mk.1A Model 7 diesels 2 shafts	2 × Kampon Mk.1A Model 10 diesels 2 shafts
Power	Surfaced	6,000 bhp		8,000 bhp	11,200 bhp
	Submerged	2,600 shp		2,600 shp	2,800 shp
Speed	Surfaced
	Submerged
Range	Surfaced	at		at	at
	Submerged	at		at	at
Test depth
Fuel		545 tons	580 tons	580 tons	800 tons
Complement		75	75	80	100
Armament (initial)		• 6 × torpedo tubes (4 × bow, 2 × aft) • 22 × Type 89 torpedoes • 2 × L/40 11th Year Type Naval guns • 1 × 7.7 mm machine gun	• 6 × torpedo tubes (4 × bow, 2 × aft) • 20 × Type 89 torpedoes • 2 × L/40 Type 88 AA guns • 1 × 7.7 mm machine gun	• 6 × torpedo tubes (4 × bow, 2 × aft) • 17 × Type 89 torpedoes • 1 × L/40 Type 88 AA gun • 1 × AA gun	• 6 × torpedo tubes (6 × bow) • 20 × Type 89 torpedoes • 2 × 140 mm L/40 11th Year Type Naval guns • 2 × 13 mm AA guns
Aircraft and facilities			• Hangar • 1 × Yokosuka E6Y1	• Catapult and hangar • 1 × Yokosuka E6Y1	• Catapult and hangar • 1 × Watanabe E9W1 Slim

Bibliography

• , History of Pacific War Vol.17 I-Gō Submarines, Gakken (Japan), January 1998, Template:ISBN
• Rekishi Gunzō, History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces", Gakken (Japan), March 2005, Template:ISBN
• 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