The Junsen type submarine (巡潜型潜水艦, "水艦", Junsen-gata sensuikan, "Cruiser submarine") 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 overview
NameJunsen type submarines
Builders
Operators Imperial Japanese Navy
Succeeded by
Subclasses
Built1923-1938
In commission1926-1945

Class variants

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The Junsen type submarines were divided into four classes:

  • Junsen I (巡潜一型(伊一型, Junsen 1-gata, I-1-class)
  • Junsen I Mod. (巡潜一型改(伊五型, Junsen 1-gata Kai, I-5-class)
  • Junsen II (巡潜二型(伊六型, Junsen 2-gata, I-6-class)
  • Junsen III (巡潜三型(伊七型, Junsen 3-gata, I-7-class).

Junsen I (I-1 class)

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I-1 in 1930

Four boats were built in 1923-1929. Genealogy of the large-size submarine in the IJN began with U-142. Japan received six U-boats from Germany as reparations of World War I. The IJN copied U-125, 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
I-1 [1] Kawasaki Shipbuilding 12-03-1923 15-10-1924 10-03-1926 Damaged USS Hulbert 31-12-1941
Sank Dutch merchant ship Siantar 03-03-1942
Sunk by HMNZS Moa and HMNZS Kiwi at Guadalcanal 29-01-1943.
I-2 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 USS Saufley north of Rabaul 02°17′S 149°14′E / 2.283°S 149.233°E / -2.283; 149.233 07-04-1944.
I-3 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.
I-4 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 USS Alhena 27-09-1942
Sunk by USS Seadragon southeast of Rabaul 05°02′S 152°33′E / 5.033°S 152.550°E / -5.033; 152.550 20-12-1942.

Junsen I Mod (I-5 class)

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I-5 in 1932

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

Boat Builder Laid down Launched Completed Results Fate
I-5 Kawasaki Shipbuilding 30-10-1929 19-06-1931 31-07-1932 Sunk by USS Wyman east of Saipan 13°01′N 151°58′E / 13.017°N 151.967°E / 13.017; 151.967 19-07-1944.

Junsen II (I-6 class)

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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
I-6 Kawasaki-Kōbe Shipyard 14 October 1932 31 March 1934 15 May 1935 Damaged aircraft carrier USS Saratoga 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)

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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
I-7 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 USS Monaghan at Kiska 21 June 1943. Scuttled 5 July 1943.
I-8 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 USS Stockton southeast of Okinawa Island 25°29′N 128°35′E / 25.483°N 128.583°E / 25.483; 128.583 31-03-1945.

Characteristics

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Type Junsen I (I-1) Junsen I Mod. (I-5) Junsen II (I-6) Junsen III (I-7)
Displacement Surfaced 1,970 long tons (2,002 t) same as Junsen I 1,900 long tons (1,930 t) 2,231 long tons (2,267 t)
Submerged 2,791 long tons (2,836 t) 3,061 long tons (3,110 t) 3,583 long tons (3,640 t)
Length (overall) 97.50 m (319 ft 11 in) 98.50 m (323 ft 2 in) 109.30 m (358 ft 7 in)
Beam 9.22 m (30 ft 3 in) 9.06 m (29 ft 9 in) 9.10 m (29 ft 10 in)
Draft 4.94 m (16 ft 2 in) 5.31 m (17 ft 5 in) 5.26 m (17 ft 3 in)
Depth 7.58 m (24 ft 10 in) 7.58 m (24 ft 10 in) 7.70 m (25 ft 3 in)
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 18.8 knots (34.8 km/h) 20.0 knots (37.0 km/h) 23.0 knots (42.6 km/h)
Submerged 8.1 knots (15.0 km/h) 7.5 knots (13.9 km/h) 8.0 knots (14.8 km/h)
Range Surfaced 24,400 nmi (45,200 km) at 10 knots (19 km/h) 20,000 nmi (37,000 km) at 10 knots (19 km/h) 14,000 nmi (26,000 km) at 16 knots (30 km/h)
Submerged 60 nmi (110 km) at 3 knots (5.6 km/h) 65 nmi (120 km) at 3 knots (5.6 km/h) 80 nmi (150 km) at 3 knots (5.6 km/h)
Test depth 75 m (246 ft) 80 m (260 ft) 100 m (330 ft)
Fuel 545 tons 580 tons 580 tons 800 tons
Complement 75 75 80 100
Armament (initial) • 6 × 533 mm (21 in) torpedo tubes
(4 × bow, 2 × aft)
• 22 × Type 89 torpedoes
• 2 × 140 mm (5.5 in) L/40 11th Year Type Naval guns[2]
• 1 × 7.7 mm machine gun
• 6 × 533 mm (21 in) torpedo tubes
(4 × bow, 2 × aft)
• 20 × Type 89 torpedoes
• 2 × 127 mm (5.0 in) L/40 Type 88 AA guns
• 1 × 7.7 mm machine gun
• 6 × 533 mm (21 in) torpedo tubes
(4 × bow, 2 × aft)
• 17 × Type 89 torpedoes
• 1 × 127 mm (5.0 in) L/40 Type 88 AA gun
• 1 × 13.2 mm (0.52 in) AA gun
• 6 × 533 mm (21 in) torpedo tubes
(6 × bow)
• 20 × Type 89 torpedoes
• 2 × 140 mm L/40 11th Year Type Naval guns[2]
• 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

Footnotes

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  1. ^ 伊号第1潜水艦 (I-Gō Dai-1 Sensuikan). The same shall apply hereinafter.
  2. ^ a b Campbell, John Naval Weapons of World War Two ISBN 0-87021-459-4 p.191

Bibliography

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  • "Rekishi Gunzō"., History of Pacific War Vol.17 I-Gō Submarines, Gakken (Japan), January 1998, ISBN 4-05-601767-0
  • 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
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