Japanese submarine I-12

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History
 Imperial Japanese Navy
NameSubmarine No. 620
BuilderKawasaki, Kobe, Japan
Laid down5 November 1942
RenamedI-12 5 July 1943
Launched3 August 1943
Commissioned25 May 1944
FateSunk 13 November 1944
Stricken10 August 1945
General characteristics
Class and typeType A2 submarine
Displacement
  • 2,920 tons surfaced
  • 4,150 tons submerged
Length113.7 m (373 ft 0 in)
Beam11.7 m (38 ft 5 in)
Draft5.89 m (19 ft 4 in)
Propulsion
  • 2 diesel engines, 4,700 hp (3,505 kW)
  • Electric motors, 1,200 hp (895 kW)
Speed
  • 17.5 knots (32 km/h; 20 mph) surfaced
  • 6.2 knots (11 km/h; 7 mph) submerged
Range
  • 22,000 nmi (41,000 km; 25,000 mi) at 16 knots (30 km/h) (surfaced)
  • 22,000 nmi (41,000 km; 25,000 mi) at 3 knots (6 km/h) (submerged)
Test depth100 m (328 ft)
Complement114
Armament
Aircraft carried1 × Yokosuka E14Y floatplane

I-12 was an Imperial Japanese Navy Type A2 long-range fleet submarine that served during World War II. Designed as a submarine aircraft carrier, she was commissioned in May 1944. Her crew committed a war crime when they attacked the survivors of a ship she sank in October 1944. She was sunk in November 1944 during her first war patrol.

Design and description[]

Type A2 submarines were versions of the preceding Type A1 with less powerful engines, adopted to reduce their construction time. I-12 was the only submarine completed to the original Type A2 design; subsequent Type A2s were constructed to a modified design as the Type AM. Like the preceding Type A1 submarines, I-12 was fitted as a squadron flagship.[2] She displaced 2,967 tonnes (2,920 long tons) on the surface and 4,217 tonnes (4,150 long tons) submerged. She was 113.7 meters (373 ft 0 in) long and had a beam of 11.7 meters (38 ft 5 in) and a draft of 5.89 meters (19 ft 4 in). She had a diving depth of 100 meters (328 ft).[2]

For surface running, I-12 powered by two 4,700-brake-horsepower (3,505 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 1,200-horsepower (895 kW) electric motor. She could reach 17.5 knots (32.4 km/h; 20.1 mph) on the surface[3] and 6.2 knots (11.5 km/h; 7.1 mph) submerged. On the surface, she had a range of 22,000 nautical miles (40,700 km; 25,300 mi) at 16 knots (30 km/h; 18 mph); submerged, she had a range of 75 nmi (139 km; 86 mi) at 3 knots (5.6 km/h; 3.5 mph).[4]

I-12 was armed with six internal bow 53.3 cm (21 in) torpedo tubes and carried a total of 18 Type 95 torpedoes. She also was armed with a single 140 mm (5.5 in)/40 deck gun and two twin 25 mm (1 in) Type 96 anti-aircraft gun mounts.[4]

As in Type A1 submarines, I-12′s aircraft hangar was integrated into her conning tower and faced forward, and the aircraft catapult was forward of the hangar, while the deck gun was aft of the conning tower. This allowed aircraft launching from I-12 to use the forward motion of the submarine to supplement the speed imparted by the catapult.[4]

Construction and commissioning[]

Built by Kawasaki at Kobe, Japan, I-12 was laid down as Submarine No. 620 on 5 November 1942.[5] On 5 July 1943 she was renamed I-12 and attached provisionally to the Yokosuka Naval District.[5] She was launched on 3 August 1943[5] and was completed and commissioned on 25 May 1944.[5]

Service history[]

May–September 1944[]

On the day of her commissioning, I-12 was formally attached to the Yokosuka Naval District and assigned to Submarine Squadron 11 in the 6th Fleet for work-ups.[5] She departed Kobe, Japan, on 20 September 1944 and conducted work-ups before arriving at Kure, Japan, on 30 September 1944.[5]

First war patrol[]

The staff of the Combined Fleet ordered the 6th Fleet to send a long-range submarine to disrupt Allied sea lines of communication between the United States West Coast and Hawaii, and the 6th Fleet selected I-12 for the operation.[5] Attached directly to 6th Fleet headquarters, she departed Kobe on 4 October 1944 for her first war patrol, ordered to attack shipping along the U.S. West Coast, in the Hawaiian Islands area, in the Tahiti area, and in the Pacific Ocean east of the Marshall Islands.[5] She proceeded through the Seto Inland Sea and Sea of Japan to Hakodate, where she paused in on 7 October 1944 for an overnight stop.[5] She then got back underway and passed through the Tsugaru Strait into the Pacific Ocean.[5]

At 21:05 on 29 October 1944, I-12 was submerged 1,000 nautical miles (1,900 km; 1,200 mi) northeast of Oahu, Hawaii, when she fired two torpedoes at the American 7,176-gross register ton Liberty ship , which was making 8.9 knots (16.5 km/h; 10.2 mph) in rough seas during a voyage from San Francisco, California, to Honolulu, Territory of Hawaii, with a cargo of trucks on her deck and 6,900 tons of food and provisions and 140 tons of explosives in her holds.[5] One torpedo passed about 50 yards (46 m) astern of John A. Johnson and exploded 2 nautical miles (3.7 km; 2.3 mi) to port and astern of her, but the other hit her on her starboard side.[5] The torpedo hit broke John A. Johnson′s keel, flooded her No. 3 hold, and destroyed one of her lifeboats.[5] John A. Johnson′s crew transmitted a distress signal.[5] The ship began to break up forward of her bridge three minutes later, and she broke in two ten minutes after the torpedo hit.[5] Her crew and United States Navy Armed Guard detachment abandoned ship, different sources giving different locations for where she was torpedoed but at least one claiming they abandoned her at

 WikiMiniAtlas
31°55′N 139°45′W / 31.917°N 139.750°W / 31.917; -139.750 (SS John A. Johnson).[5] One of her lifeboats foundered, but her 70 survivors[citation needed] abandoned her in Lifeboats No. 2 and 4 and a life raft.[5]

I-12 surfaced 30 minutes later.[5] She opened gunfire on both sections of John A. Johnson, and after she fired eight 140-millimeter (5.5 in) rounds, both sections were on fire.[5] I-12 then attempted to ram Lifeboat No. 2, and some of its occupants jumped overboard.[5] I-12 merely brushed the lifeboat, but then opened fire with her 25 mm antiaircraft guns on the survivors on the life raft.[5] She then rammed the life raft and attempted to ram Lifeboat No. 4, but missed it.[5] Sources differ on casualties, but at least six men were killed,[5] and one claims that four crewmen, five Navy Armed Guard personnel, and John A. Johnson′s security officer were left missing and presumed dead.[5] At 01:05 on 30 October 1944, John A. Johnson′s bow section exploded, sending flames 700 feet (213 m) into the air, and sank.[5] Her burning stern section remained afloat.[5] The Japanese erroneously credited I-12 with sinking two ships.[5] A Pan American World Airways Boeing 314 Clipper flying boat sighted the wreckage and survivors, and the United States Navy patrol vessel USS Argus (PY-14) rescued them 24 hours after John A. Johnson sank,[5] at 21:35 on 30 October 1944.[citation needed] Argus disembarked the survivors at San Francisco on 3 November 1944.[5] They described I-12 as a very large submarine, painted black or dark grey above the waterline and light grey below it, with a 6-inch (15 cm) horizontal stripe running around her stern.[5]

A U.S. Navy hunter-killer group centered around the escort carrier USS Corregidor (CVE-58) began to search for I-12, and TBM Avenger aircraft from Corregidor reported that they attacked unidentified submarines on 2 and 4 November 1944.[5] Some sources have claimed that the New Zealand four-masted barque Pamir sighted I-12 at

 WikiMiniAtlas
24°31′N 146°47′W / 24.517°N 146.783°W�� / 24.517; -146.783 on 12 November 1944,[5] but this hypothesis largely has been discredited,[5] and according to one source it is more likely that Pamir sighted the U.S. Navy submarine USS Spot (SS-413).[5]

Loss[]

On 13 November 1944, the U.S. Navy minesweeper USS Ardent (AM-340) and the United States Coast Guard-manned U.S. Navy patrol frigate USS Rockford (PF-48) were escorting a six-ship convoy at about the midpoint of its voyage from Honolulu to San Francisco when at 12:32 Ardent′s sonar detected a submerged submarine ahead of the convoy 1,000 nautical miles (1,900 km; 1,200 mi) west-southwest of Los Angeles, California.[5][6] Ardent attacked first at 12:41, firing a 24-charge pattern of Hedgehog projectiles, and again at 12:46 with a second Hedgehog pattern.[5][6] No projectiles hit the submarine.[5] Rockford left her escort station to assist, and fired her first Hedgehog barrage of 13 projectiles at 13:08;[5] 15 seconds later[5] her crew heard either two explosions before a large underwater detonation rocked the ship,[6] or three distinct detonations followed four minutes later by numerous underwater explosions,[5] according to different sources. Ardent carried out two more Hedgehog attacks and Rockford dropped 13 depth charges to ensure the submarine′s destruction.[5][6] After more explosions Ardent and Rockford lost all contact with the submarine[5][6] at either

 WikiMiniAtlas
31°55′N 139°45′W / 31.917°N 139.750°W / 31.917; -139.750 (I-12) or
 WikiMiniAtlas
31°48′N 139°52′W / 31.800°N 139.867°W / 31.800; -139.867 (I-12), according to different sources.[5] Diesel oil, air bubbles, and debris including teak deck planks, ground cork covered in diesel oil, pieces of varnished mahogany inscribed in Japanese, a wooden slat from a vegetable crate with Japanese writing and advertisements on it, and a piece of an instrument case inscribed with Japanese characters.[5][6] Both Ardent and Rockford received credit for the probable destruction of a Japanese submarine, which probably was I-12.[5][6]

On 19 December 1944, 6th Fleet headquarters ordered I-12 to return to Kure,[5] but she did not acknowledge receipt of the message. However, Japanese signals intelligence intercepted Allied communications indicating the sinking of an Allied transport and tanker in the mid-Pacific Ocean between 20 and 31 December 1944[5] and U.S. Navy sightings of a Japanese submarine in the Hawaiian Islands area on 2 and 4 January 1945, leading the 6th Fleet staff to conclude that I-12 still was on patrol.[5] The 6th Fleet staff also assessed that a garbled interception of an Allied report of a surfaced Japanese submarine seen north of the Marshall Islands at

 WikiMiniAtlas
14°10′N 171°02′E / 14.167°N 171.033°E / 14.167; 171.033 on 5 January 1945 was a sighting of I-12 as she returned from her patrol.[5] On 31 January 1945, however, the Imperial Japanese Navy declared I-12 to be presumed lost with all 114 hands in the mid-Pacific Ocean.[5] The Japanese removed her from the navy list on 10 August 1945.[5]

References[]

Footnotes[]

  1. ^ Campbell, John Naval Weapons of World War Two ISBN 0-87021-459-4 p. 191
  2. ^ a b Bagnasco, p. 188
  3. ^ Chesneau, p. 200
  4. ^ a b c Carpenter & Dorr, p. 101
  5. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay Hackett, Bob; Kingsepp, Sander (29 July 2019). "IJN Submarine I-12: Tabular Record of Movement". combinedfleet.com. Retrieved 23 December 2021.
  6. ^ a b c d e f g Boyd & Yoshida, p. 209.

Bibliography[]

  • Boyd, C; Yoshida, A (1995). The Japanese Submarine Force and World War II. Annapolis, MD: Naval Institute Press.
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