| History | |
|---|---|
 Imperial Japanese Navy | |
| Name | Submarine No. 620 |
| Builder | Kawasaki,Kobe, Japan |
| Laid down | 5 November 1942 |
| Renamed | I-12 on 5 July 1943 |
| Launched | 3 August 1943 |
| Commissioned | 25 May 1944 |
| Fate | Sunk 13 November 1944 |
| Stricken | 10 August 1945 |
| Service record | |
| Part of | Submarine Squadron 11[1] |
| Commanders |
|
| General characteristics | |
| Class & type | Type A2 submarine |
| Displacement |
|
| Length | 113.7 m (373 ft 0 in) |
| Beam | 11.7 m (38 ft 5 in) |
| Draft | 5.89 m (19 ft 4 in) |
| Propulsion |
|
| Speed |
|
| Range |
|
| Test depth | 100 m (328 ft) |
| Complement | 114 |
| Armament |
|
| Aircraft carried | 1 ×Yokosuka E14Yfloatplane |
I-12 was anImperial Japanese NavyType A2 long-range fleetsubmarine that served duringWorld War II. Designed as asubmarine aircraft carrier, she was commissioned in May 1944. Her crew committed awar 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.
Type A2 submarines were versions of the precedingType 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 theType AM. Like the preceding Type A1 submarines,I-12 was fitted as asquadronflagship.[3] Shedisplaced 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 abeam of 11.7 meters (38 ft 5 in) and adraft of 5.89 meters (19 ft 4 in). She had a diving depth of 100 meters (328 ft).[3]
For surface running,I-12 powered by two 4,700-brake-horsepower (3,505 kW)diesel engines, each driving onepropeller shaft. When submerged each propeller was driven by a 1,200-horsepower (895 kW)electric motor. She could reach 17.5knots (32.4 km/h; 20.1 mph) on the surface[4] and 6.2 knots (11.5 km/h; 7.1 mph) submerged. On the surface, she had a range of 22,000nautical 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).[5]
I-12 was armed with six internalbow 53.3 cm (21 in)torpedo tubes and carried a total of 18Type 95torpedoes. She also was armed with a single140 mm (5.5 in)/40deck gun and two twin25 mm (1 in) Type 96anti-aircraft gunmounts.[5]
As in Type A1 submarines,I-12′s aircrafthangar was integrated into herconning tower and faced forward, and theaircraft catapult was forward of the hangar, while the deck gun was aft of theconning tower. This allowed aircraft launching fromI-12 to use the forward motion of the submarine to supplement the speed imparted by the catapult.[5]
Built byKawasaki atKobe,Japan,I-12 waslaid down asSubmarine No. 620 on 5 November 1942.[6] On 5 July 1943 she was renamedI-12 and attached provisionally to theYokosuka Naval District.[6] She waslaunched on 3 August 1943[6] and was completed andcommissioned on 25 May 1944.[6]
On the day of her commissioning,I-12 was formally attached to the Yokosuka Naval District and assigned to SubmarineSquadron 11 in the6th Fleet for work-ups,[6] with CommanderKaneo Kudo in command, who remained her commanding officer for the submarine's entire career.[1] She departedKobe, Japan, on 20 September 1944 and conducted work-ups before arriving atKure, Japan, on 30 September 1944.[6]
The staff of theCombined Fleet ordered the 6th Fleet to send a long-range submarine to disruptAlliedsea lines of communication between theUnited States West Coast andHawaii, and the 6th Fleet selectedI-12 for the operation.[6] 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 theHawaiian Islands area, in theTahiti area, and in thePacific Ocean east of theMarshall Islands.[6] She proceeded through theSeto Inland Sea andSea of Japan toHakodate, where she paused inHakodate Bay on 7 October 1944 for an overnight stop.[6] She then got back underway and passed through theTsugaru Strait into the Pacific Ocean.[6]
During the early hours of 28 October 1944,[7] the American 7,176-gross register tonLiberty shipSS John A. Johnson — which had departedSan Francisco,California, on 24 October with 41 crewmen, 28United States Navy Armed Guard personnel, and aUnited States Army cargo security officer aboard bound forHonolulu,Territory of Hawaii,[8] with a cargo of crated and uncrated U.S. Armytrucks on her deck and 6,900 tons of food and provisions[6][8] and 140[6] or 150[8] tons (according to different sources) of explosives in herholds[6] — broke radio silence for 12 minutes to report the loss overboard in heavy seas of alife raft, a common practice in peacetime to avoid unnecessarysearch-and-rescue operations if the raft was found, despite the suspension of such reports during World War II due to the wartime proliferation of rafts and wreckage and the need to maintain communications security.[7]I-12, on the surface to recharge her batteries at the time, intercepted the transmission, fixedJohn A. Johnson′s position, and steered to intercept her.[9] At 21:05 on 29 October 1944,I-12 was submerged 1,000 nautical miles (1,900 km; 1,200 mi) northeast ofOahu, Hawaii, when she fired twotorpedoes atJohn A. Johnson, which was making 8.9 knots (16.5 km/h; 10.2 mph) in rough seas.[6][10] One torpedo passed about 50 yards (46 m) astern ofJohn 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 herstarboard side immediately forward of thebridge.[6][11] The torpedo hit brokeJohn A. Johnson′skeel, flooded her No. 3 hold, and destroyed one of herlifeboats, and she quickly lost all electrical power.[6][12]John A. Johnson′s crew transmitted adistress signal reporting her position as29°55′N141°25′W / 29.917°N 141.417°W /29.917; -141.417.[6][12] The ship began to break up forward of herbridge three minutes later, and she broke in two ten minutes after the torpedo hit.[6][13] Her crew and U.S. Navy Armed Guard detachment abandoned ship, different sources giving different locations for where she was torpedoed but at least one claiming they abandoned her at31°55′N139°45′W / 31.917°N 139.750°W /31.917; -139.750 (SSJohn A. Johnson).[6] One of her lifeboats foundered, but all 70 men on board abandoned her in Lifeboats No. 2 and 4 and alife raft.[6][14]
I-12 surfaced 30 minutes later[6][14] and steered toward the lifeboats at high speed.[14] She attempted to ram Lifeboat No. 2, and some of its occupants jumped overboard.[6]I-12 merely brushed the lifeboat, but immediately opened fire on its occupants and men in the water who had jumped out of the boat with her 25 mmantiaircraft guns as 10 to 15 members of her crew on deck shoutedBanzai! after each burst ofautomatic weapons fire.[14] For 45 minutes,I-12 moved about in the vicinity of the lifeboats, attempting to ram Lifeboat No. 4, discovering the life raft with 17 survivors aboard and opening fire on it with her 25-millimeter guns, all the while shooting any survivors she found and attempting to slice up men in the water with herpropellers.[6][14] She then opened gunfire on both sections ofJohn A. Johnson from a range of 2,000 yards (1,800 m), and after she fired eight 140-millimeter (5.5 in) rounds, scoring four hits, both sections were on fire.[6][15] She remained on the scene for another two hours, although she did not resume firing at the remaining survivors, who believed that she was waiting for dawn so that she could continue the massacre in daylight.[15]
Just after 01:00 on 30 October 1944, aPan American World AirwaysBoeing 314 Clipperflying boat flying from San Francisco to Honolulu sighted the two burning halves ofJohn A. Johnson, the lifeboats, andI-12 on the surface nearby.[15] Theairliner's crew and passengers also sawJohn A. Johnson′s bow section explode at 01:05, sending flames 700 feet (213 m) into the air, after which it sank.[6][15] Her burning stern section remained afloat.[6] The aircraft reported the sighting to authorities in San Francisco, who in turn notified theUnited States Navypatrol vesselUSS Argus, whose crew had heard the explosion ofJohn A. Johnson′s bow section from 90 nautical miles (170 km; 100 mi) away and already was headed toward the scene.[6] A search-and-rescue aircraft sighted the survivors at 08:00 on 30 October,[15] and at 14:00Argus reached the scene and brought aboard 60 survivors.[16]Argus disembarked the survivors at San Francisco on 3 November 1944.[6][17] They describedI-12 as a very large submarine, painted black or dark grey above thewaterline and light grey below it, with a 6-inch (15 cm) horizontal stripe running around herstern.[6]
Sources differ on casualties during the sinking and subsequent massacre, but at least six men were killed.[6] One source claims that four crewmen, five Navy Armed Guard personnel, and the U.S. Army cargo security officer were left missing and presumed dead,[6] and another specifies that 10 men died.[17] BecauseJohn A. Johnson broke in two, the Japanese erroneously creditedI-12 with sinking two ships.[6]
A U.S. Navyhunter-killer group centered around theescort carrierUSS Corregidor began to search forI-12, andTBM Avenger aircraft fromCorregidor reported that they attacked unidentified submarines on 2 and 4 November 1944.[6] Some sources have claimed that theNew Zealand four-mastedbarquePamir sightedI-12 at24°31′N146°47′W / 24.517°N 146.783°W /24.517; -146.783 on 12 November 1944,[6] but this hypothesis largely has been discredited,[6] and according to one source it is more likely thatPamir sighted the U.S. Navy submarineUSS Spot.[6]
On 13 November 1944, the U.S. NavyminesweeperUSS Ardent and theUnited States Coast Guard-crewed U.S. Navypatrol frigateUSS Rockford were escorting a six-shipconvoy at about the midpoint of its voyage from Honolulu to San Francisco when at 12:32Ardent′ssonar detected a submerged submarine ahead of the convoy 1,000 nautical miles (1,900 km; 1,200 mi) west-southwest ofLos Angeles, California.[6][18]Ardent attacked first at 12:41, firing a 24-charge pattern ofHedgehog projectiles, and again at 12:46 with a second Hedgehog pattern.[6][18] No projectiles hit the submarine.[6]Rockford left her escort station to assist, and fired her first Hedgehog barrage of 13 projectiles at 13:08.[6] Fifteen seconds later[6] her crew heard either two explosions before a large underwater detonation rocked the ship,[18] or three distinct detonations followed four minutes later by numerous underwater explosions,[6] according to different sources.Ardent carried out two more Hedgehog attacks andRockford dropped 13depth charges to ensure the submarine′s destruction.[6][18] After more explosionsArdent andRockford lost all contact with the submarine[6][18] at either31°55′N139°45′W / 31.917°N 139.750°W /31.917; -139.750 (I-12) or31°48′N139°52′W / 31.800°N 139.867°W /31.800; -139.867 (I-12), according to different sources.[6]Diesel oil, air bubbles, and debris includingteak deck planks, groundcork covered in diesel oil, pieces ofvarnishedmahogany inscribed inJapanese, 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.[6][18] BothArdent andRockford received credit for the probable destruction of a Japanese submarine, which probably wasI-12.[6][18]
On 19 December 1944, 6th Fleet headquarters orderedI-12 to return to Kure,[6] but she did not acknowledge receipt of the message. However, Japanesesignals intelligence intercepted Allied communications indicating the sinking of an Alliedtransport andtanker in the mid-Pacific Ocean between 20 and 31 December 1944[6] 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 thatI-12 still was on patrol.[6] 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 at14°10′N171°02′E / 14.167°N 171.033°E /14.167; 171.033 on 5 January 1945 was a sighting ofI-12 as she returned from her patrol.[6] On 31 January 1945, however, the Imperial Japanese Navy declaredI-12 to be presumed lost with all 114 hands in the mid-Pacific Ocean.[6] The Japanese removed her from the navy list on 10 August 1945.[6]
