| History | |
|---|---|
 Japan | |
| Name | Submarine No. 208 |
| Builder | Sasebo Naval Arsenal,Sasebo,Japan |
| Laid down | 27 April 1942 |
| Renamed | Ro-42 on 25 September 1942 |
| Launched | 25 October 1942 |
| Completed | 31 August 1943 |
| Commissioned | 31 August 1943 |
| Fate | Sunk 11 June 1944 |
| Stricken | 10 August 1944 |
| General characteristics | |
| Class and type | Kaichū type submarine (K6 subclass) |
| Displacement |
|
| Length | 80.5 m (264 ft 1 in) overall |
| Beam | 7 m (23 ft 0 in) |
| Draft | 4.07 m (13 ft 4 in) |
| Installed power |
|
| Propulsion |
|
| Speed |
|
| Range |
|
| Test depth | 80 m (260 ft) |
| Crew | 61 |
| Armament |
|
Ro-42 was anImperial Japanese NavyKaichū type submarine of the K6sub-class. Completed and commissioned in August 1943, she served inWorld War II and was sunk in June 1944 during her third war patrol.
The submarines of the K6 sub-class were versions of the preceding K5 sub-class with greater range and diving depth.[1] Theydisplaced 1,133 tonnes (1,115 long tons) surfaced and 1,470 tonnes (1,447 long tons) submerged. The submarines were 80.5 meters (264 ft 1 in) long, had abeam of 7 meters (23 ft 0 in) and adraft of 4.07 meters (13 ft 4 in). They had a diving depth of 80 meters (260 ft).[2]
For surface running, the boats were powered by two 2,100-brake-horsepower (1,566 kW)diesel engines, each driving onepropeller shaft. When submerged each propeller was driven by a 600-horsepower (447 kW)electric motor.[3] They could reach 19.75knots (36.58 km/h; 22.73 mph) on the surface and 8 knots (15 km/h; 9.2 mph) underwater. On the surface, the K6s had a range of 11,000nautical miles (20,000 km; 13,000 mi) at 12 knots (22 km/h; 14 mph); submerged, they had a range of 45 nmi (83 km; 52 mi) at 5 knots (9.3 km/h; 5.8 mph).[1]
The boats were armed with four internal bow 53.3 cm (21.0 in)torpedo tubes and carried a total of tentorpedoes. They were also armed with a single76.2 mm (3.00 in) L/40anti-aircraft gun and two single25 mm (1.0 in) AA guns.[1]
Ro-42 waslaid down asSubmarine No. 208 on 27 April 1942 by theSasebo Navy Yard atSasebo,Japan.[4] She was renamedRo-42 on 25 September 1942 and was attached provisionally to theMaizuru Naval District that day.[4] She waslaunched on 25 October 1942[4] and was completed andcommissioned on 31 August 1943.[4]
Upon commissioning,Ro-42 was attached formally to the Maizuru Naval District and assigned to SubmarineSquadron 11 for workups.[4] On 30 November 1943, she was reassigned to Submarine Division 34 in the6th Fleet,[4] and on 4 December 1943 she departedMaizuru, Japan, bound forTruk, which she reached on 12 December 1943.[4]
Ro-40 got underway from Truk on 23 December 1943 to begin her first war patrol, assigned a patrol area offEspiritu Santo in theNew Hebrides.[4] She was 200 nautical miles (370 km; 230 mi) east of Espiritu Santo on 14 January 1944 when shetorpedoed the 800-tonUnited States Navyfuel oilbargeUSS YO-159, which her commanding officer had mistaken for a 10,000-tonfleet oiler, at15°27′S171°28′E / 15.450°S 171.467°E /-15.450; 171.467 (USSYO-159).[4]YO-159 suffered such serious damage that U.S. forces laterscuttled her.[4]Ro-42 returned to Truk on 24 January 1944.[4] She took aboard torpedoes from the auxiliarysubmarine tenderHeian Maru there on 28 January 1944.[4]
DuringRo-42′s stay at Truk, U.S. NavyTask Force 58 conductedOperation Hailstone, a major attack on Truk bycarrier aircraft supported by anti-shipping sweeps around theatoll by surface warships, on 17 and 18 February 1944.[4]Ro-42 and the submarinesI-10 andRo-36 put to sea on 17 February in an attempt to intercept the attacking ships.[4]Ro-42 was unsuccessful, and returned to Truk on 19 February 1944.[4]
Ro-42 began her second war patrol on 25 February 1944, departing Truk to head for a patrol area east ofKusaie.[4] On 1 March she received orders to conduct a reconnaissance ofKwajalein and then move to a new patrol area 120 nautical miles (220 km; 140 mi) southeast of Kwajalein.[4] After she arrived off Kwajalein, she reported on 4 March 1944 that the island′s waters were too heavily patrolled byAlliedpatrol boats for her to approach it for a reconnaissance.[4]Ro-42 also began to suffer from malfunctioning equipment.[4] She was ordered to return to her patrol.[4]
Ro-42 was 40 nautical miles (74 km; 46 mi) southwest ofMili Atoll in theMarshall Islands when she sighted aconvoy of sixtransports at 08:00 on 6 March 1944.[4] WHile 70 nautical miles (130 km; 81 mi) southwest of Mili on 15 March 1944, she reported sighting abattleship and fiveaircraft carriers of U.S. NavyTask Group 50.10, prompting the commander-in-chief of the 6th Fleet,Vice AdmiralTakeo Takagi, to order the submarinesRo-36 andRo-44 to intercept the ships.[4]
On 16 March 1944,Ro-42 received orders to move 100 nautical miles (190 km; 120 mi) to the west-southwest,[4] and on 18 March to move another 80 nautical miles (150 km; 92 mi) to the west.[4] She was 240 nautical miles (440 km; 280 mi) south ofPonape on 21 March 1944 when she sighted a three-shipconvoy.[4] On 23 March 1944, she and the submarinesI-16,Ro-36,Ro-41,Ro-43,Ro-44, andRo-108 were ordered to intercept a U.S. Navy task force that the submarineI-32 had sighted 60 nautical miles (110 km; 69 mi) north ofJaluit Atoll that day.[4] She did not find the task force, and she returned to Truk on 28 March 1944.[4]
Ro-42 got underway from Truk in company with the submarinesI-174,Ro-36,Ro-48, andRo-108 on 12 April 1944 to intercept an Allied task force Japanese forces had sighted north ofKavieng.[4] She returned to Truk on 14 April.[4] On 23 April 1944 she departed Truk bound forYokosuka, Japan, which she reached on 30 April 1944.[4]
On 15 May 1944,Ro-42 departed Yokosuka with the commander of Submarine Division 34 embarked and orders to conduct a reconnaissance of the American fleet anchorage atMajuro and then proceed to an area north-northeast of Kwajalein.[4] While she was at sea, she received orders to postpone the Majuro reconnaissance until 10 June 1944.[4] On 10 June 1944, she was operating in the Marshall Islands when she was ordered to reconnoiter both Majuro and Kwajalein.[4]
Ro-42 was on the surface 40 nautical miles (74 km; 46 mi) east ofRoi-Namur at 23:30 on 10 June 1944 when thedestroyer escortUSS Bangust (DE-739) detected her onradar.[4] AfterBangust closed, made visual contact, and flashed a challenge,Ro-42 crash-dived.[4]Bangust searched for the submergedRo-42 for the next eight hours and regained contact onsonar on the morning of 11 June 1944.[4]Bangust conducted three unsuccessful 24-projectileHedgehog attacks asRo-42 made evasive maneuvers such as frequent hard turns and sudden changes in speed.[4] However, her fourth Hedgehog attack resulted in a large underwater explosion that damagedBangust′shull.[4]Ro-42 tried to surface, but failed, and sank at10°05′N168°22′E / 10.083°N 168.367°E /10.083; 168.367 (Ro-42).[4] During the morning of 11 June, a large oil slick was sighted on the surface.[4]
On 13 June 1944 theCombined Fleet activated Operation A-Go for the defense of theMariana Islands, and that day Vice Admiral Takagi ordered all available Japanese submarines to deploy east of the Marianas,[4] withRo-42 ordered to head there at flank speed.[4] On 16 June 1944, she was assigned to Submarine Group B and ordered to move to an area southeast of the Marianas,[4] and on 22 June 1944 she was ordered to return to Truk.[4] She acknowledged none of the orders. On 12 July 1944, the Imperial Japanese Navy declaredRo-42 to be presumed lost with all 73 hands.[4] She was stricken from the Navy list on 10 August 1944.[4]
Some historians have identified a Japanese submarine the U.S. submarineUSS Sea Devil (SS-400) sank on 16 September 1944 east of Japan asRo-42, but the submarineSea Devil sank probably wasI-364.[4]
