Wreck of HIJMS RO-42

 Second World War 1939-1945, shipwreck

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HIJMS RO-42 was a Kaichū Type VII Submarine laid down at the Sasebo Navy Yard in April 1942 and commissioned into the Imperial Japanese Navy in August 1943 as a member of Submarine Squadron 11, Division 34 IJN Sixth Fleet. After type training in the Inland Sea, the RO-42 and her crew departed Japan for Truk where she began her first War Patrol on December 23rd, 1943.

Patrolling off the Allied Base at Espiritu Santo, the RO-42 sighted and torpedoed the US Navy Yard Oiler USS YO-159 on January 14th, 1944 for her first kill of the war and returned to Truk ten days later for reprovisioning and refit. While alongside a Tender in Truk Lagoon, the crew of RO-48 learned of the American invasion of several islands in the Marshalls chain on January 31 and began hastily preparing for their next deployment. While finalizing voyage preparations and completing routine maintenance, the RO-42 and all the other ships in Truk Lagoon came under concentrated air attack from US Navy forces on February 17th but managed to escape the major damage inflicted on the surface ships by submerging in the lagoon until the US planes withdrew. That night the RO-42 put to sea to try to hunt down the American Fleet but returned to Truk the following day having found no traces of her quarry and completed her repairs.

RO-42's second war patrol took her to the waters off Kwajalein Atoll where she hunted US Navy forces engaged in airstrikes and amphibious assaults, and while she spotted and reported numerous surface contacts, including the four carriers of Task Group 50.10, heavy anti-submarine patrols and unfortunate timing meant the RO-42 could only report her sightings and returned to Truk in late March. After returning to Japan for an overhaul of her onboard electrical systems and a change of command, the RO-42' third War Patrol commenced in May 1944 with orders to reconnoiter Majuro and Kwajalein Atoll in preparation for a Japanese assault. Arriving on station in early June, the RO-42 began her clandestine recon work by periscope by day and by visual means while transmitting her findings by night.

Running on the surface on the night of June 10th off Kwajalein, the RO-42's crew went about their routine of transmitting the days findings and used the inclement weather's cancellation of the night's recon to relax. As she operated off shore her radar signature was picked up by the crew of the USS Bangust (DE-739) at 2325hrs, a US Destroyer Escort steaming independently for Roi. Unaware of any friendly ships in her area, the Bangust quickly closed to investigate the contact, the foul weather both preventing her from being seen and from her lookouts sighting the mystery ship until they were only 300 yards apart. Sighting the RO-42 as she emerged from a rain squall, the crew aboard the Bangust sent out a challenge using her signal lamp which sent the surprised crew of RO-42 scrambling below decks and initiating a crash-dive as the Bangust began firing starshells to illuminate the ship off her Starboard bow.

RO-42's crew took their sub deep at 2348hrs and rigged for silent running, unable to attack the American ship due to its proximity when it had suddenly appeared. Utilizing battle tactics and maneuvers the RO-42's skipper remained undetected for over eight hours as his counterpart aboard the Bangust conducted sonar sweeps of the area, occasionally dropping depth charges on suspected contacts but finding no result. The cat-and-mouse game between the two ships continued unabated until shortly before 0700hrs on June 11th, when sonar operators aboard Bangust regained contact their quarry in deep water and began lobbing salvoes of 'hedgehog' anti-submarine mortars into the deep. On her fourth 24-round salvo the Bangust found her mark and caused a underwater explosion so massive that it opened seams in her own hull, which was followed by two more muffled underwater explosions shortly thereafter. Within minutes, the sea was coated in a large oil slick and debris field, signifying the loss of the HIJMS RO-42 and all 73 of her crew at this location on June 11th, 1944.

www.combinedfleet.com/RO-42.htm