 Oblique view ofRyūjō at speed, 6 September 1934 | |
| Class overview | |
|---|---|
| Operators |  Imperial Japanese Navy |
| Preceded by | Kaga |
| Succeeded by | Sōryū |
| Built | 1929–1931 |
| In commission | 1931–1942 |
| Completed | 1 |
| Lost | 1 |
| History | |
 Empire of Japan | |
| Name | Ryūjō |
| Builder | Mitsubishi,Yokohama |
| Laid down | 26 November 1929 |
| Launched | 2 April 1931 |
| Commissioned | 9 May 1933 |
| Stricken | 10 November 1942 |
| Fate | Sunk during theBattle of the Eastern Solomons, 24 August 1942 |
| General characteristics (as built) | |
| Type | Light aircraft carrier |
| Displacement | |
| Length | 179.9 meters (590 ft 3 in) (o/a) |
| Beam | 20.32 meters (66 ft 8 in) |
| Draught | 5.56 meters (18 ft 3 in) |
| Installed power |
|
| Propulsion | 2 × shafts; 2 × gearedsteam turbines |
| Speed | 29knots (54 km/h; 33 mph) |
| Range | 10,000 nmi (19,000 km; 12,000 mi) at 14 knots (26 km/h; 16 mph) |
| Complement | 600 |
| Armament |
|
| Aircraft carried | 48 |
| General characteristics (1936) | |
| Displacement |
|
| Beam | 20.78 meters (68 ft 2 in) |
| Draught | 7.08 meters (23 ft 3 in) |
| Complement | 934 |
| Armament |
|
Ryūjō (Japanese:龍驤 "Prancing Dragon") was a lightaircraft carrier built for theImperial Japanese Navy (IJN) during the early 1930s. Small and lightly built in an attempt to exploit a loophole in theWashington Naval Treaty of 1922, she proved to be top-heavy and only marginallystable and was back in theshipyard for modifications to address those issues within a year of completion. With her stability improved,Ryūjō returned to service and was employed in operations during theSecond Sino-Japanese War. During World War II, she provided air support for operations inthe Philippines,Malaya, and theDutch East Indies, where her aircraft participated in theSecond Battle of the Java Sea. During theIndian Ocean raid in April 1942, the carrier attacked British merchant shipping with her guns and aircraft.Ryūjō next participated in theBattle of Dutch Harbor, the opening battle of theAleutian Islands campaign, in June 1942. She was sunk by American carrier-based aircraft in theBattle of the Eastern Solomons on 24 August 1942.
Ryūjō was planned as a light carrier of around 8,000metric tons (7,900long tons)standard displacement[1] to exploit a loophole in theWashington Naval Treaty of 1922 that carriers under 10,000 long tons (10,000 t) standard displacement were not regarded as "aircraft carriers".[2][3] WhileRyūjō was under construction, Article Three of theLondon 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.[4]
Ryūjō had a length of 179.9 meters (590 ft 3 in)overall.[1] with abeam of 20.32 meters (66 ft 8 in) and adraft of 5.56 meters (18 ft 3 in). Shedisplaced 8,000 metric tons (7,900 long tons) at standard load and 10,150 metric tons (9,990 long tons) at normal load. Her crew consisted of 600 officers and enlisted men.[5]
To keepRyūjō's weight to 8,000 metric tons, the hull was lightly built with no armor; some protective plating was added abreast the machinery spaces andmagazines. She was also designed with only a singlehangar, which would have left an extremely low profile (there being just 4.6 meters (15 ft 1 in) offreeboardamidships and 3.0 meters (9 ft 10 in) 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 14.9 meters (48 ft 11 in). Coupled with the ship's narrow beam, the consequent top-heaviness made her minimally stable in rough seas, despite the fitting ofSperry activestabilizers. This was a common flaw amongst many treaty-circumventing Japanese warships of her generation.[6]
TheTomozuru Incident of 12 March 1934, in which a top-heavytorpedo 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 theKure Naval Arsenal for modifications that strengthened her keel and addedballast and shallowtorpedo bulges to improve her stability. Herfunnels were moved higher up the side of her hull and curved downward to keep the deck clear of smoke.[7]
Shortly afterward,Ryūjō was one of many Japanese warships caught in atyphoon on 25 September 1935 while on maneuvers during the "Fourth Fleet Incident." The ship'sbridge,flight deck and superstructure were damaged and the hangar was flooded. Theforecastle was raised one deck and the bow was remodelled with moreflare to improve the sea handling.[7] After these modifications, the beam and draft increased to 20.78 meters (68 ft 2 in) and 7.08 meters (23 ft 3 in) respectively. The displacement also increased to 10,600 metric tons (10,400 long tons) at standard load and 12,732 metric tons (12,531 long tons) at normal load. The crew also grew to 924 officers and enlisted men.[5]
The ship was fitted with two gearedsteam turbine sets with a total of 65,000shaft horsepower (48,000 kW), each driving onepropeller shaft, using steam provided by sixKamponwater-tube boilers.Ryūjō had a designed speed of 29knots (54 km/h; 33 mph), but reached 29.5 knots (54.6 km/h; 33.9 mph) during hersea trials from 65,270 shp (48,670 kW). The ship carried 2,490 long tons (2,530 t) offuel oil, which gave her a range of 10,000nautical miles (19,000 km; 12,000 mi) at 14 knots (26 km/h; 16 mph). The boiler uptakes were trunked to the ship's starboard side amidships and exhausted horizontally below flight deck level through two small funnels.[8]
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Ryūjō was aflush-decked carrier without anislandsuperstructure; 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 23.5 meters (77 ft 1 in) from the ship'sstem, givingRyūjō a distinctive open bow. The 156.5-meter (513 ft 5 in) flight deck was 23 meters (75 ft 6 in) wide and extended well beyond the aft end of the superstructure, supported by a pair of pillars. Six transversearrestor wires were installed on the flight deck and were modernised in 1936 to stop a 6,000 kg (13,000 lb) aircraft.[6] The ship's hangars were both 102.4 meters (335 ft 11 in) long and 18.9 meters (62 ft 0 in) wide, and had an approximate area of 3,871 square metres (41,667 sq ft).[9] Between them, they gave the ship the capacity to store 48 aircraft, but only 37 could be operated at one time.[6] After theFourth Fleet incident,Ryūjō's bridge and the leading edge of the flight deck were rounded off to make them more streamlined. This reduced the length of the flight deck by 2 meters (6 ft 7 in).[7]
Aircraft were transported between the hangars and the flight deck by twoelevators; the forward platform measured 15.7 by 11.1 meters (51.5 ft × 36.4 ft) and the rear 10.8 by 8.0 meters (35.4 ft × 26.2 ft).[9] The small rear elevator became a problem as the IJN progressively fielded larger and more modern carrier aircraft. Of all the aircraft in front-line service in 1941, only theNakajima B5N "Kate"torpedo bomber would fit, when positioned at an angle with its wings folded. This effectively madeRyūjō a single-elevator carrier and considerably hindered transfer of aircraft in and out of the hangars for rearming and refueling during combat operations.[6]
As completed,Ryūjō's primaryanti-aircraft (AA) armament comprised six twin-gun mounts equipped with 40-caliber12.7-centimeter Type 89dual-purpose guns mounted on projectingsponsons, three on either side of the carrier's hull.[8] When firing at surface targets, the guns had a range of 14,700 meters (16,100 yd); they had a maximum ceiling of 9,440 meters (30,970 ft) at their maximum elevation of +90 degrees. Their maximum rate of fire was 14 rounds a minute, but their sustained rate of fire was around eight rounds per minute.[10] Twenty-four anti-aircraft (AA) Type 9313.2 mm Hotchkiss machine guns were also fitted, in twin[8] and quadruple mounts.[7] Their effective range against aircraft was 700–1,500 meters (770–1,640 yd). The cyclic rate was adjustable between 425 and 475 rounds per minute, but the need to change 30-roundmagazines reduced the effective rate to 250 rounds per minute.[11]
During the carrier's 1934–1936 refit, two of the 12.7-centimeter (5.0 in) mountings were exchanged for two twin-gun mounts forlicense-builtHotchkiss25 mm Type 96 light AA guns,[7] resulting in a reduction of approximately 60 long tons (61 t) of top-weight that improved the ship's overall stability.[6] This was the standard Japanese light AA gun during World War II, but it suffered from severe design shortcomings that rendered it a largely ineffective weapon. According to historian Mark Stille, the weapon had many faults including an inability to "handle high-speed targets because it could not be trained or elevated fast enough by either hand or power, its sights were inadequate for high-speed targets, [and] it possessed excessive vibration and muzzle blast."[12] These 25-millimeter (0.98 in) guns had an effective range of 1,500–3,000 meters (1,600–3,300 yd), and an effective ceiling of 5,500 meters (18,000 ft) 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.[13] The machine guns were replaced during a brief refit in April–May 1942 with six triple-mount 25-millimeter (0.98 in) AA guns.[7]
Following theJapanese ship-naming conventions for aircraft carriers,Ryūjō was named "Prancing Dragon".[14] The ship waslaid down at theMitsubishi'sYokohama shipyard on 26 November 1929. She waslaunched on 2 April 1931, towed toYokosuka Naval Arsenal on 25 April forfitting out, andcommissioned on 9 May 1933 with CaptainToshio Matsunaga in command. While training in mid-1933, her initial air group consisted of nineMitsubishi B1M2 (Type 13) torpedo bombers, plus three spares, and threeA1N1 (Type 3)fighters, plus two spares. Matsunaga was relieved by CaptainTorao Kuwabara on 20 October. After the Tomozuru Incident, the ship was reconstructed from 26 May to 20 August 1934.[15]
CaptainIchiro Ono assumed command on 15 November 1934 andRyūjō became the flagship ofRear AdmiralHideho Wada'sFirst Carrier Division. The following month the ship was chosen to evaluatedive-bombing tactics using sixNakajima E4N2-C Type 90reconnaissance aircraft, sixYokosuka B3Y1 Type 92 torpedo bombers, and a dozenA2N1 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 theIJN 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 CaptainShun'ichi Kira.[15]
In mid-1936, the ship was used to evaluate a dozenAichi D1A dive bombers and dive-bombing tactics. She also embarked at that time 24A4N1 fighters, plus four and eight spare aircraft respectively. In September,Ryūjō resumed her role as flagship of First Carrier Division, now commanded by Rear AdmiralSaburō Satō. Her air group now consisted of a mixture of B3Y1 torpedo bombers, D1A1 dive bombers and A2N fighters, but her torpedo bombers were transferred after fleet maneuvers in October demonstrated effective dive bombing tactics. CaptainKatsuo Abe assumed command of the ship on 16 November.[15]
The First Carrier Division arrived offShanghai on 13 August 1937 to support operations of theJapanese Army inChina. Her aircraft complement consisted of 12 A4N fighters (plus four spares) and 15 D1A dive bombers. The dive bombers attacked targets in and near Shanghai.[15] The Japanese fighters had their first aerial engagement on 22 August when four A4Ns surprised 18NationalistCurtiss Hawk III fighters and claimed to have shot down six without loss. The following day, four A4Ns claimed to have shot down nine Chinese fighters without loss to themselves.[16] The carriers returned toSasebo at the beginning of September to resupply before arriving off the South China coast on 21 September to attack Chinese forces nearCanton.[15] Nine fighters fromRyūjō escorted a raid on the city and claimed six of the defending fighters. While escorting another raid later that day, the Japanese pilots claimed five aircraft shot down and one probably shot down.[16] The dive bombers attacked targets near Canton until the ship sailed to the Shanghai area on 3 October. Her air group was flown ashore on 6 October to support Japanese forces near Shanghai andNanking.Ryūjō returned home in November and briefly became a training ship before she was assigned to Rear AdmiralTomoshige Samejima'sSecond Carrier Division.[15]
In February 1938 the ship replaced her A4Nbiplanes with nineMitsubishi A5M "Claude"monoplane fighters. The division supported Japanese operations in Southern China in March–April and again in October. CaptainKiichi Hasegawa assumed command on 15 November 1939.Ryūjō was given a refit that lasted from December 1939 through January 1940 and became a training ship until November when she became the flagship of Rear AdmiralKakuji Kakuta'sThird Carrier Division. Hasegawa was relieved by CaptainUshie Sugimoto on 21 June. The ship's air group then consisted of 18 Nakajima B5N torpedo bombers and 16 A5M4 fighters. When theFirst Air Fleet was formed on 10 April 1941,Ryūjō became flagship of theFourth Carrier Division.[15]
The ship's assignment at the beginning of thePacific War was to support the invasion of thePhilippines, initially by attacking the American naval base atDavao,Mindanao, on the morning of 8 December.[Note 1] Her air group had not changed, but four of each type of aircraft were spares.Ryūjō's 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 twoConsolidated PBYseaplanes 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 Britishoil tanker south of Davao.[17] In January 1942 her aircraft supported Japanese operations in theMalay Peninsula.[15]
In mid-February 1942,Ryūjō's aircraft attacked ships evacuating fromSingapore, claiming eight ships damaged, three burnt, and four sunk. They also covered convoys carrying troops toSumatra. The ship was unsuccessfully attacked by severalBristol Blenheim light bombers ofNo. 84 Squadron RAF on 14 February. The following day two waves of B5Ns, totaling 13 aircraft, attacked the Britishheavy cruiserExeter, but managed only to damage the ship'sSupermarine Walrus seaplane. Follow-on attacks the same day were also unsuccessful. Two days later, B5Ns destroyedHNLMS Van Ghent, a Dutch destroyer that had run aground in theGaspar Strait and been abandoned on 14 February.[18] The carrier sailed toSaigon,French Indochina, the next day and arrived on 20 February. A week later she was assigned to cover the convoy taking troops toJakarta,Java.[15] Her aircraft participated in the Second Battle of the Java Sea on 1 March and six B5Ns sank the American destroyerPope after it had been abandoned by its crew.[19] Six other B5Ns bombed the port ofSemarang, possibly setting one merchantman on fire.[15]
Ryūjō arrived in Singapore on 5 March and the ship supported operations in Sumatra and escorted convoys toBurma and theAndaman Islands for the rest of the month.[15] On 1 April, while the 1st Air Fleet was startingits raid in the Indian Ocean, Malay Force, consisting ofRyūjō, sixcruisers, and fourdestroyers, left Burma on a mission to destroy merchant shipping in theBay of Bengal. B5Ns damaged one freighter on 5 April before the force split into three groups.Ryūjō's aircraft bombed the small ports ofCocanada andVizagapatam on the southeastern coast of India the next day, doing little damage, in addition to claiming two ships sunk and six more damaged during the day. The carrier and her escorts, the light cruiserYura and the destroyerYūgiri, claimed to have sunk three more ships by gunfire. All together, Malay Force sank 19 ships totaling almost 100,000 gross register tons (GRT),[20] 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.[15]
The newly commissioned carrierJun'yō joined Carrier Division 4, under the command of Kakuta, withRyūjō on 3 May 1942. They formed the core of the 2nd Carrier Strike Force, part of the Northern Force, tasked to attack theAleutian Islands, an operation planned to seize several of the islands to provide advance warning in case of an American attack from the Aleutians down theKurile Islands while the main body of the American fleet was occupieddefending Midway.Ryūjō's air group now consisted of 12 A6M2 Zeros and 18 B5Ns,[21] plus two spares of each type. The ship transferred toMutsu Bay on 25 May and then toParamushiro on 1 June before departing the same day for the Aleutians.[15]
At dawn on 3 June, she launched 9 B5Ns, escorted by 6 Zeros, to attackDutch Harbor onUnalaska Island. One B5N crashed on takeoff but 6 of the B5Ns and all of the Zeros were able to make it through the bad weather, destroying two PBYs and inflicting significant damage on theoil storage tanks and barracks. A second airstrike was launched later in the day to attack a group of destroyers discovered by aircraft from the first attack, but they failed to find the targets. One Zero fromRyūjō from the second strike was damaged by aCurtiss P-40 and crash landed on the island ofAkutan. The aircraft, later dubbed theAkutan Zero, remained largely intact and was later salvaged by the U.S. Navy and test flown. On the following day, the two carriers launched another airstrike, consisting of 15 Zeros, 11 D3As, and 6 B5Ns, which successfully bombed Dutch Harbor. Shortly after the aircraft were launched, the Americans attacked the carriers, but failed to inflict any damage. AMartin B-26 Marauder bomber and a PBY were shot down by Zeros, and aBoeing B-17 Flying Fortress bomber was shot down byflak during the attack.[22]
Ryūjō arrived back at Mutsu Bay on 24 June, and departed for the Aleutians four days later to cover the second reinforcement convoy toAttu andKiska 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.[15]
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TheAmerican landings on Guadalcanal and Tulagi on 7 August caught the Japanese by surprise. The next day,Ryūjō was transferred to Carrier Division 1 and departed forTruk on 16 August together with the other two carriers of the division,Shōkaku andZuikaku. Her air group consisted of 24 Zeros and nine B5N2s.[23] AdmiralIsoroku Yamamoto,commander-in-chief of theCombined Fleet, ordered Truk to be bypassed and the fleet refueled at sea after an American carrier was spotted near theSolomon Islands on 21 August.[24] At 01:45 on 24 August, Vice AdmiralChūichi Nagumo, commander of the Mobile Force, orderedRyūjō and the heavy cruiserTone, escorted by two destroyers, detached to move in advance of the troop convoy bound forGuadalcanal and to attack the Allied air base atHenderson Field if no carriers were spotted. This Detached Force was commanded by Rear AdmiralChūichi Hara inTone.[25]
Ryūjō launched two small airstrikes, totaling 6 B5Ns and 15 Zeros, beginning at 12:20 once the Diversionary Force was 200 nautical miles (370 km; 230 mi) north ofLunga Point. FourGrumman F4F Wildcat fighters fromMarine Fighter SquadronVMF-223 oncombat air patrol (CAP) near Henderson Field spotted the incoming Japanese aircraft around 14:20 and alerted the defenders. Ten more Wildcats from VMF-223 andVMF-212scrambled, as well as 2United States Army Air CorpsBell P-400s from the67th Fighter Squadron in response. Nine of the Zerosstrafed the airfield while the B5Ns bombed it with 60-kilogram (132 lb) 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.[26]
Around 14:40, the Detached Force was spotted again by several search aircraft from the carrierUSS Enterprise; 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 searchingGrumman TBF Avenger torpedo bombers narrowly missedRyūjō 150 meters (164 yd) astern with four 500-pound (227 kg) 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 carrierUSS Saratoga had launched an airstrike against the Detached Force in the early afternoon that consisted of 31Douglas SBD Dauntlesses and eight Avengers; the long range precluded fighter escort. They found the carrier shortly afterward and attacked. They hitRyūjō three times with 1,000-pound (454 kg) bombs and one torpedo; the torpedo hit flooded the starboard engine and boiler rooms. No aircraft from eitherRyūjō orSaratoga were shot down in the attack.[27]
The bomb hits set the carrier on fire and she took on alist 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 destroyerAmatsukaze moved alongside to rescue the crew. The ships were bombed several times by multiple B-17s without effect beforeRyūjō capsized about 17:55 at coordinates06°10′S160°50′E / 6.167°S 160.833°E /-6.167; 160.833 with the loss of seven officers and 113 crewmen.[15] Fourteen aircraft that she had dispatched on raids returned shortly afterRyūjō sank and circled over the force until they were forced toditch. Seven pilots were rescued.[28]
