Wreck of HIJMS Taiyō (大鷹)

 navy, shipwreck, aircraft carrier

Laid down in January 1940 as the Kasuga Maru and built as a commercial ocean liner for the Nippon Yusen Shipping Line, the Kasuga Maru was still in the process of fitting out for her commercial service life when she was requisitioned by the Imperial Japanese Navy for use as a military transport. Retaining her original name when she began military service in March 1941, the liner made several transport runs between Japan and her outlying territories before she the decision was made to convert the ship and her two sisterships into Escort Aircraft Carriers in advance of the coming war with the United States.

Undergoing an extensive conversion at the Sasebo Navy Yard from May through September 1941, the Kasuga Maru ceased to exist as she formally commissioned into service with the Imperial Japanese Navy on September 1st as HIJMS Taiyō, the lead ship of her class of three Escort Carriers. After briefly serving as Flagship of Carrier Division 5 for her sea trials and workups, the Taiyō was reassigned to Carrier Division 4 and began her Naval service as an aircraft transport ship between Japan, Palau, Truk and Rabaul, bringing fresh aircraft to the front lines and returning damaged aircraft to Japan for reconstruction. Operating almost entirely in convoys as she plied the ocean expanses of the Greater East Asia Co-Prosperity Sphere, the Taiyō and her crew found little contact with their enemy during her first year of service, aside from harassment air raids while at Rabaul.

As 1942 progressed the number of American and Allied Submarine attacks on Japanese convoys began to steadily increase, but Taiyō and her crew saw no increase to her anti-submarine capabilities or her screening escorts despite the growing threat. The perceived lack of protection and the danger posed by American Subs became reality as Taiyō was steaming in convoy between Davao and Truk on September 28th, 1942 when the USS Trout (SS-202) struck her with a single torpedo on her Stern, killing 13 of her crew and causing moderate damage to the ship. Damaged but still able to make headway, the Taiyō completed her mission but was forced back to Japan for full repairs which lasted until November 1942, after which Taiyō resumed her aircraft ferry work.

Attacked again while enroute to Truk in April 1943 by the USS Tunny (SS-282), faulty torpedoes likely spared the Taiyō from total destruction as no fewer than four slammed into her hull but failed to detonate, leaving the ship with four large depressions in her hull but no serious damage. Attacked unsuccessfully four months later by USS Pike (SS-173) while enroute to Yokosuka from Truk, the Taiyō was transiting the same route the following month when she was attacked and struck by a single torpedo fired by USS Cabrilla (SS-288). Shearing off her Port propeller and having her Starboard shaft heavily warped as a result of the blast, the Taiyō went dead in the water as her escorts pressed an attack on the American Submarine, keeping it deep long enough for Taiyō to be placed under tow to Yokosuka where she spent two months under repair before returning to service in late November 1943.

Fitted with her own sonar system to aid in the detection of Submarine threats as she operated in the now-severely threatened Japanese convoy system, Taiyō and her crew again resumed their wartime duties as aircraft transporters through April 1944, at which time Taiyō’s capabilities as an Escort Carrier were finally put to use. Assigned to the First Surface Escort Unit and shipping her first operational airwing of the entire war, the Taiyō began escorting merchant and naval convoys between mainland Japan, Singapore and the Philippines as Allied forces made steady inroads into Japan’s once sizeable empire. With the American Submarine threat continuing to exact a staggering toll on Japanese merchant shipping, Taiyō’s role of providing anti-submarine air cover became doubly important and hazardous as 1944 progressed.

Attached to merchant convoy HI-71 bound for Singapore via Manila on August 10th, 1944, Taiyō screened her charges as they moved first to Mako in and then across the South China Sea to Luzon’s West Coast, where Japanese land-based aircraft were available to augment Taiyō’s anti-submarine air cover. Using foul weather to try to conceal their movements as they moved South towards Manila, Taiyō and her convoy were picked up by radar operators aboard the first of three American Submarines operating as a wolfpack; USS Rasher (SS-269). Moving immediately to attack while surfaced, Rasher’s Captain eventually sank three ships in the convoy while evading the largely ineffective anti-submarine attacks by the convoy’s escorts. Slowly rising back to periscope depth and drawing a bead on what appeared to be an enormous oil tanker steaming at the center of the convoy, Rasher’s Captain loaded his final four torpedoes into his bow tubes and sent them into the path of the enemy ship at 2215hrs.

Aboard Taiyō, alert sonarmen easily picked up the sound of torpedoes in the water and quickly identified a Submarine contact to Starboard, prompting the ship’s Captain to order flank speed and an evasive turn to Starboard as lookouts spotted four approaching torpedoes heading straight for the ship. Hoping to comb the inbound shots, the lumbering Carrier managed to evade the first two to Port but was caught on her Starboard quarter by at least one of the remaining torpedoes, which detonated directly beneath the ship’s aft aviation gas bunker. Almost immediately an enormous gasoline explosion rocked the ship and coated much of the rear quarter of the vessel in flames, killing or severely injuring dozens of crew and bringing the Taiyō down by the Stern and beginning to list to Starboard. Immediately ordering the Portside ammunition magazines flooded to reduce their risk of explosion and to counter the ship’s list, Taiyō’s Captain ordered all damage control parties to the hangar deck to fight the rapidly growing fire as he swung the ship into the wind with her last momentum to keep the fires aft. With the majority of the damage control teams deployed and staging in her hangar, the Taiyō’s rear bunker oil tank failed and released its contents into the already burning Stern area, resulting in another enormous explosion. The force of the blast sent a powerful pressure wave, shrapnel and a wall of fire tearing through the Carriers hangar deck, killing or severely burning every crewman mustered there.

With the ship now heavily aflame, suffering dozens of low order explosions and with almost no crew left alive to counteract or contain the damage, Taiyō’s Captain issued the order for the ship to be abandoned only fifteen minutes after the initial torpedo impact. As her few surviving crew scrambled to get topside, another enormous explosion tore through the ship causing the entire Stern to begin to separate from the rest of the hull and an unknown numbers of casualties. With her surviving crew and passengers in the water, HIJMS Taiyō continued to flounder wreathed in a pool of burning gasoline and oil before breaking in two and rapidly sinking at this location at 2248hrs on August 18th, 1944.

www.combinedfleet.com/taiyo.htm