Indian Ocean raid
The Indian Ocean raid, also known as Operation C[2] or Battle of Ceylon in Japanese, was a naval sortie carried out by the Imperial Japanese Navy (IJN) from 31 March to 10 April 1942. Japanese aircraft carriers under Admiral Chūichi Nagumo struck Allied shipping and naval bases around British Ceylon, but failed to locate and destroy the bulk of the British Eastern Fleet. The Eastern Fleet, commanded by Admiral Sir James Somerville, was forewarned by intelligence and sailed from its bases prior to the raid; its attempt to attack the Japanese was frustrated by poor tactical intelligence.
"Operation C" redirects here. For the 1991 video game, see Operation C (video game).Following the attack the British expected a major Japanese offensive in the Indian Ocean. The main base of the Eastern Fleet relocated to East Africa, and Ceylon was reinforced, but Somerville kept his fast carrier division, Force A, "...in Indian waters, to be ready to deal with any attempt by the enemy to command those waters with light forces only."[3] However, the Japanese had no short-term plans to follow up on their success, and within the year operations in the Pacific made it impossible to do so.
Background[edit]
Strategic situation[edit]
The island of Ceylon was strategically important, since it commanded the Indian Ocean. Thus it controlled access to India, the vital Allied shipping routes to the Middle East and the oilfields of the Persian Gulf. Ceylon held most of the British Empire's resources of rubber. An important harbour and naval base, Trincomalee, was located on the island’s eastern coast. Japanese propaganda had an effect on some of the Sinhalese population, who now awaited their arrival.
The fall of Singapore on 15 February 1942 broke the United Kingdom's eastern defensive perimeter of the Bay of Bengal; and the Japanese occupation of the Andaman Islands on 23 March gave Japan control of the Andaman Sea enabling ships to resupply Japanese troops in the Burma Campaign for control of India. Both German and British authorities anticipated Japanese capture of Ceylon to solidify control of the Bay of Bengal and disrupt British resupply for defence of India, Australia, and perhaps the Middle East. Ceylon was hastily garrisoned by Australian troops returning from North Africa; and HMS Indomitable was relieved of naval duties to serve as a high-speed aircraft ferry shuttling available planes to Ceylon.[4]
Japanese intentions to mount a major offensive into the Indian Ocean were placed on hold in March 1942; strong naval forces were needed in the western Pacific against the United States, and the Imperial Japanese Army (IJA) refused to allocate troops for an invasion of Ceylon. In response, the IJN developed Operation C, a plan for an aggressive raid into the Indian Ocean in early April. Operation C aimed to destroy the British Eastern Fleet, and disrupt British lines of communications in the Bay of Bengal in support of the Burma Campaign.[2]
British intelligence correctly assessed the Japanese strategy. The Americans were notified; the Doolittle Raid – which was already in progress – took on the additional role of a diversion.[2]
Japanese preparations[edit]
Admiral Isoroku Yamamoto issued the initial order to proceed with Operation C to the IJN's southern force, commanded by Admiral Nobutake Kondō, on 9 March 1942. By 16 March, the plan was to depart from Staring Bay, Celebes, on 26 March for an attack on Colombo ("C day") on 5 April.[5] The Japanese expected to destroy the British Eastern Fleet in port.[6]
The Japanese force, commanded by Admiral Chūichi Nagumo, had a core of five aircraft carriers; Akagi, Shōkaku and Zuikaku in Carrier Division 5, and Sōryū and Hiryū in Carrier Division 2.[1] The carriers were accompanied by all four Kongo-class battleships, and both Tone-class cruisers.[7]
Japanese intelligence on the composition of the British Eastern Fleet in the Indian Ocean[8] was reasonably accurate,[6]
while overestimating the air strength on Ceylon.[6] The 19 March operational order vaguely advised that a "considerable" portion of British naval and air forces in the Indian Ocean were "deployed in Ceylon area".[8]
The Japanese stationed reconnaissance submarines outside of the known British anchorages at Colombo and Trincomalee; their effectiveness was limited.[9] At least one submarine was sent to scout the Maldive Islands but failed to detect Port T at Addu Atoll.[10]
At the same time as Operation C, the IJN also dispatched Malay Force under the command of Vice Admiral Jisaburō Ozawa. His force consisted of the aircraft carrier Ryūjō, six cruisers, and four destroyers to destroy shipping in the Bay of Bengal on 1 April. Malay Force was not part of Operation C.[11]
In 3 days, Ozawa's force managed to sink 23 merchant ships (20 in a single day),[12] totaling over 130,000 gross registered tons.[13] In addition, April saw 32,000 tons of shipping sunk by Japanese submarines off India's west coast.[12] Ryūjō's aircraft also bombed the ports of Cocanada and Vizagapatam, causing relatively minor damage.[12] The tonnage and number of ships sunk by Malay Force, are comparable to that of the 3-month long Operation Berlin raid conducted by two battleships of the Kriegsmarine from January to March 1941.[14] In both raids against merchant shipping, Allied merchant ships were not sailing in convoys escorted by large vessels.[15]
Aftermath[edit]
British reaction[edit]
The Japanese inflicted disproportionate damage on the enemy. They damaged port facilities, sank one carrier and two cruisers, destroyed a third of enemy ground-based fighters and nearly all of the enemy ground-based strike aircraft. In addition, 23 merchant ships,[45] totalling 112,312 tons,[46] were sunk, including those by the separate Japanese Malay Force. In return, the Japanese lost only 18 aircraft (six fighters, ten dive-bombers and two high-level bombers), with damage to about 31 more. Conversely, they failed to destroy, or even locate, the main bulk of the British Eastern Fleet.[45]
The British interpreted their position as precarious. Ceylon and the Eastern Fleet were required to safeguard the sea lines of communications through the Indian Ocean. The British expected the Japanese to continue threatening these lines. SIGINT suggested that the Japanese were preparing a deliberate advance across the Indian Ocean.[53] The raid demonstrated that the RAF was too weak to defend Ceylon and the naval anchorages,[3] and that the navy was ill-prepared to meet a Japanese carrier force.[54]
The Eastern Fleet transferred its main base to Kilindini, Kenya in East Africa, temporarily ceding the eastern Indian Ocean to the Japanese; from there it continued contesting control of the central Indian Ocean on better terms.[53] Force A, including its two aircraft carriers, Indomitable and Formidable, retired to Bombay,[3] and Somerville regularly deployed a fast carrier force to the central Indian Ocean over the next six months, during which he operated from or near Ceylon for nearly half that time. On 18 April, naval planning accorded the Eastern Fleet the highest priority for reinforcement, which also included transferring most of the carriers from the Home Fleet and the Mediterranean, with the intention of returning to Ceylon in September.[55]
By June, Ceylon was defended by three RAF squadrons (64 aircraft, plus reserves), three strike squadrons (including one of Beauforts), and much improved radar and anti-aircraft defences.[56] Ground defences were manned by two Australian army brigades.[57]
The invasion scare was short-lived. British intelligence detected the movement of the Japanese carrier force eastward in mid-April, and their deployment in the Pacific in mid-May.[58] After the Battle of Midway in June, it was realized that there was no longer the threat of major Japanese naval activity in the Indian Ocean. In September, British intelligence predicted Japan would go over to the defensive. As a result, the Eastern Fleet was not reinforced as planned and, instead, shrank after early July.[59]
Japanese reaction[edit]
The Japanese did not exploit their victory as the British feared. The decision to postpone major operations in the Indian Ocean was upheld. The Japanese aircraft carriers required maintenance and replenishment after months of intensive operations,[60] and there was already difficulty in maintaining the strength of frontline air units.[61] Nagumo and officers such as Mitsuo Fuchida (commanding Akagi's air group) felt that the losses inflicted on the British did not justify the loss of experienced Japanese air crews.[62] Japanese attention also lay elsewhere. In early May, Japanese carriers fought the Battle of the Coral Sea in the southwest Pacific,[60] followed in June by the Battle of Midway.[59] In both cases, losses constrained Japanese options further.
In June, the IJA developed a plan for a major offensive in the Indian Ocean, including an invasion of Ceylon. The Germans were advancing in North Africa, which made an Axis link-up in the Middle East attractive. Resource constraints forced the IJN to reject it, especially once the Guadalcanal Campaign started.[59]
Subsequently, the limit of Japanese operations in the Indian Ocean was against trade using submarines and armed merchant cruisers.[63] Notably, a submarine group patrolling off East Africa attacked the harbour at Diego-Suarez, Madagascar, while the Allies were capturing the island.[64] Ironically, the Allies were motivated by fears that the Japanese might establish a base there to attack trade.[56] Overall, Japanese attacks on trade enjoyed some success, but after 1942 the presence of major Japanese naval units in the Indian Ocean virtually ceased.[65]
Criticism of Nagumo[edit]
Nagumo's leadership has been characterized by Andrew Boyd as rigid and unimaginative, and contributed to the escape of the British Eastern Fleet. The manoeuvring of his fleet was mainly to facilitate strikes on Colombo and Trincomalee; the possibility that the enemy might be at sea was apparently not seriously considered. He failed to appreciate that the direction that Dorsetshire's force was sailing, and the later appearance of British carrier-based aircraft, were related. Furthermore, due to limited aerial reconnaissance, Nagumo had little concrete information of what was around him, especially to his front and exposed flanks. He was not served by the confidence that there was nothing else to be found outside of the few searches made.[6]
The limited air searches conducted at the start of the battle reflected contemporary IJN practice, where the intensity of air searches was scaled according to expected threats. The stronger morning search on 6 April reflected the suspicion that British carriers might be present. The intensity of later air searches dropped off when the British carriers were not found and there was little expectation of encountering them. Ultimately, all navies suffered from inadequate air search planning during this period.[66]
Problems with Japanese carrier operations[edit]
The raid also provided early examples of problems with Japanese carrier operations. Inadequate aerial reconnaissance failing to locate the enemy fleet in a timely fashion, the difficulty of rearming aircraft for a different mission at short notice, and the penetration of the CAP by enemy aircraft due to the lack of radar-directed fighter control would all recur at the Battle of Midway.[6]
Criticism of Somerville[edit]
Somerville's leadership was characterized by a willingness to take risks, bordering on recklessness.
The initial deployment of the fleet on 30 March endangered the British fleet in multiple ways. Somerville was relying on radar – manned by inexperienced personnel – to locate the enemy and facilitate night strikes. If the Japanese approached as expected from the southeast and the British failed to find the Japanese before dawn, the distance between the two fleets would be no more than 100 miles (160 km); the British would be detected by Japanese aerial reconnaissance at dawn and be subject to air attack for the entire day. Much the same could have been expected had Somerville still been on station when the Japanese arrived – as they did – from the southwest.[9] Somerville's decision to refuel at Port T – rather than on Ceylon – on 2 April allowed the Eastern Fleet to avoid Nagumo a few days later, and likely saved the Eastern Fleet from destruction.[10]
The failure of the Japanese fleet to appear on 1–2 April led Somerville to mistakenly believe that the entirety, rather than a part, of Allied intelligence concerning Operation C was flawed. As a result he detached Cornwall, Dorsetshire, and Hermes, which were subsequently lost after being sent into areas overflown by Japanese aerial reconnaissance.[10]
Andrew Boyd notes:
The disquieted Admiralty broadly agreed.[67]
Somerville faced challenges not experienced by the RN in the Atlantic or Mediterranean. Japanese air superiority made it difficult to scout, close, and attack during the day. Radar-enabled night attack was the only viable offensive option. This was a high-risk strategy. A combination of careful positioning, luck, and Japanese errors nearly produced the preconditions for a strike on the night of 5 April; the enemy was within 125 miles (201 km) – 1-hour flight range in an Albacore – but accurate information on the enemy's vector was missing. Even then, it required experienced air crews to find their targets at night, using radar with a range of just 20 miles (32 km) and new tactics.[68]