Japanese aircraft carrier Ryūjō

Ryūjō ( "Prancing Dragon") was a light aircraft carrier built for the Imperial Japanese Navy (IJN) during the early 1930s. Small and lightly built to exploit a loophole in the Washington Naval Treaty of 1922, she proved to be top-heavy and only marginally stable and was back in the shipyard for modifications within a year of completion. With her stability improved, Ryūjō returned to service and was employed in operations during the Second Sino-Japanese War.

During World War II, she provided air support for operations in the Philippines, Malaya, and the Dutch East Indies, where her aircraft participated in the Second Battle of the Java Sea. During the Indian Ocean raid in April 1942, the carrier attacked British merchant shipping. Ryūjō was next in the Battle of Dutch Harbor, the opening battle of the Aleutian Islands campaign, in June 1942. She was sunk by American carrier-based aircraft in the Battle of the Eastern Solomons on 24 August 1942.

Design

Ryūjō was planned as a light carrier of around standard displacement While Ryūjō was under construction, Article Three of the London Naval Treaty of 1930 closed the above-mentioned loophole; consequently, Ryūjō was the only light aircraft carrier of her type to be completed by Japan.

Ryūjō had a length of overall. with a beam of and a draft of . She displaced at standard load and at normal load. Her crew consisted of 600 officers and enlisted men.

thumb|left|Bow view of Ryūjō, 19 June 1933

To keep Ryūjōs weight to 8,000 metric tons, the hull was lightly built with no armor; some protective plating was added abreast the machinery spaces and magazines. She was also designed with only a single hangar, which would have left an extremely low profile (there being just of freeboard amidships and aft). Between the time the carrier was laid down in 1929 and launched in 1931, the Navy doubled her aircraft stowage requirement to 48 in order to give her a more capable air group. This necessitated the addition of a second hangar atop the first, raising freeboard to . Coupled with the ship's narrow beam, the consequent top-heaviness made her minimally stable in rough seas, despite the fitting of Sperry active stabilizers. This was a common flaw amongst many treaty-circumventing Japanese warships of her generation.

The Tomozuru Incident of 12 March 1934, in which a top-heavy torpedo boat capsized in heavy weather, caused the IJN to investigate the stability of all their ships, resulting in design changes to improve stability and increase hull strength. Ryūjō, already known to be only marginally stable, was promptly docked at the Kure Naval Arsenal for modifications that strengthened her keel and added ballast and shallow torpedo bulges to improve her stability. Her funnels were moved higher up the side of her hull and curved downward to keep the deck clear of smoke.

thumb|Ryūjō at anchor in 1936 after reconstruction

Shortly afterward, Ryūjō was one of many Japanese warships caught in a typhoon on 25 September 1935 while on maneuvers during the "Fourth Fleet Incident." The ship's bridge, flight deck and superstructure were damaged and the hangar was flooded. The forecastle was raised one deck and the bow was remodelled with more flare to improve the sea handling.

Flight deck and hangars

right|thumb|Starboard and overhead diagrams of Ryūjō

Ryūjō was a flush-decked carrier without an island superstructure; the navigating and control bridge was located just under the forward lip of the flight deck in a long glassed-in "greenhouse", whilst the superstructure was set back from the ship's stem, giving Ryūjō a distinctive open bow. The flight deck was wide and extended well beyond the aft end of the superstructure, supported by a pair of pillars. Six transverse arrestor wires were installed on the flight deck and were modernised in 1936 to stop a aircraft. Between them, they gave the ship the capacity to store 48 aircraft, but only 37 could be operated at one time. Twenty-four anti-aircraft (AA) Type 93 13.2 mm Hotchkiss machine guns were also fitted, in twin

During the carrier's 1934–1936 refit, two of the mountings were exchanged for two twin-gun mounts for Hotchkiss 25 mm Type 96 light AA guns, These guns had an effective range of , and an effective ceiling of at an elevation of +85 degrees. The maximum effective rate of fire was only between 110 and 120 rounds per minute because of the need to frequently change the fifteen-round magazines. The machine guns were replaced during a brief refit in April–May 1942 with six triple-mount AA guns. The ship was laid down at the Mitsubishi's Yokohama shipyard on 26 November 1929. She was launched on 2 April 1931, towed to Yokosuka Naval Arsenal on 25 April for fitting out, and commissioned on 9 May 1933 with Captain Toshio Matsunaga in command. While training in mid-1933, her initial air group consisted of nine Mitsubishi B1M2 (Type 13) torpedo bombers, plus three spares, and three A1N1 (Type 3) fighters, plus two spares. Matsunaga was relieved by Captain Torao Kuwabara on 20 October. After the Tomozuru Incident, the ship was reconstructed from 26 May to 20 August 1934.

Captain Ichiro Ono assumed command on 15 November 1934 and Ryūjō became the flagship of Rear Admiral Hideho Wada's First Carrier Division. The following month the ship was chosen to evaluate dive-bombing tactics using six Nakajima E4N2-C Type 90 reconnaissance aircraft, six Yokosuka B3Y1 Type 92 torpedo bombers, and a dozen A2N1 Type 90 fighters. The reconnaissance aircraft proved to be unsuitable after several months' testing. Ryūjō participated in the Combined Fleet Maneuvers of 1935 where she was attached to the IJN Fourth Fleet. The fleet was caught in a typhoon on 25 September and the ship was moderately damaged. Ryūjō arrived at Kure on 11 October 1935 for repairs, modifications, and a refit that lasted until 31 May 1936. On 31 October Ono was relieved by Captain Shun'ichi Kira. The carriers returned to Sasebo at the beginning of September to resupply before arriving off the South China coast on 21 September to attack Chinese forces near Canton. Her air group had not changed, but four of each type of aircraft were spares. Ryūjōs initial airstrike consisted of 13 B5Ns escorted by nine A5Ms with a smaller airstrike later in the day by two B5Ns and three A5Ms. They accomplished little, destroying two Consolidated PBY seaplanes on the ground for the loss of one B5N and one A5M. The ship covered the landing at Davao on 20 December and her B5Ns attacked a British oil tanker south of Davao. In January 1942 her aircraft supported Japanese operations in the Malay Peninsula. The carrier sailed to Saigon, French Indochina, the next day and arrived on 20 February. A week later she was assigned to cover the convoy taking troops to Jakarta, Java. Six other B5Ns bombed the port of Semarang, possibly setting one merchantman on fire. before reuniting on 7 April and arriving at Singapore on 11 April. A week later, her B5Ns were detached for torpedo training and the ship arrived at Kure on 23 April for a brief refit. plus two spares of each type. The ship transferred to Mutsu Bay on 25 May and then to Paramushiro on 1 June before departing the same day for the Aleutians.

Ryūjō arrived back at Mutsu Bay on 24 June, and departed for the Aleutians four days later to cover the second reinforcement convoy to Attu and Kiska Islands and remained in the area until 7 July in case of an American counterattack. She arrived at Kure on 13 July for a refit and was transferred to Carrier Division 2 a day later. Admiral Isoroku Yamamoto, commander-in-chief of the Combined Fleet, ordered Truk to be bypassed and the fleet refueled at sea after an American carrier was spotted near the Solomon Islands on 21 August. At 01:45 on 24 August, Vice Admiral Chūichi Nagumo, commander of the Mobile Force, ordered Ryūjō and the heavy cruiser , escorted by two destroyers, detached to move in advance of the troop convoy bound for Guadalcanal and to attack the Allied air base at Henderson Field if no carriers were spotted. This Detached Force was commanded by Rear Admiral Chūichi Hara in Tone.

Ryūjō launched two small airstrikes, totaling 6 B5Ns and 15 Zeros, beginning at 12:20 once the Diversionary Force was north of Lunga Point. Four Grumman F4F Wildcat fighters from Marine Fighter Squadron VMF-223 on combat air patrol (CAP) near Henderson Field spotted the incoming Japanese aircraft around 14:20 and alerted the defenders. Ten more Wildcats from VMF-223 and VMF-212 scrambled, as well as 2 United States Army Air Corps (USAAC) Bell P-400s from the 67th Fighter Squadron in response. Nine of the Zeros strafed the airfield while the B5Ns bombed it with bombs to little effect. The Americans claimed to have shot down 19 aircraft, but only three Zeros and three B5Ns were lost, with another B5N forced to crash-land. Only three Wildcats were shot down in turn.

Around 14:40, the Detached Force was spotted again by several search aircraft from the carrier ; the Japanese ships did not immediately spot the Americans. They launched three Zeros for a combat air patrol at 14:55, three minutes before two of the searching Grumman TBF Avenger torpedo bombers narrowly missed Ryūjō astern with four bombs. Two more Zeros reinforced the patrol shortly after 15:00, just in time to intercept two more searching Avengers, shooting down one. In the meantime, the carrier had launched an airstrike against the Detached Force in the early afternoon that consisted of 31 Douglas SBD Dauntlesses and eight Avengers; the long range precluded fighter escort. They found the carrier shortly afterward and attacked. They hit Ryūjō three times with bombs and one torpedo; the torpedo hit flooded the starboard engine and boiler rooms. No aircraft from either Ryūjō or Saratoga were shot down in the attack.

The bomb hits set the carrier on fire and she took on a list from the flooding caused by the torpedo hit. Ryūjō turned north at 14:08, but her list continued to increase even after the fires were put out. The progressive flooding disabled her machinery and caused her to stop at 14:20. The order to abandon ship was given at 15:15 and the destroyer moved alongside to rescue the crew. The ships were bombed several times by multiple B-17s without effect before Ryūjō capsized about 17:55 at coordinates with the loss of seven officers and 113 crewmen.

Japanese aircraft carrier Ryūjō

Design

Flight deck and hangars

Notes

Footnotes

Bibliography

External links