In early April 1942, the Imperial Japanese Navy launched Operation C, a plan to repeat the success of Pearl Harbor by surprising the Royal Navy and destroying the British Eastern Fleet in its home port of Colombo, Ceylon. What the Japanese did not know was that the Allies had partially broken their codes and were aware of the operation. The British reinforced their forces in Ceylon and prepared to set a trap. In a plan reminiscent of the Battle of Midway, which would take place a few months later, the Royal Navy carrier force would lie in wait roughly one hundred miles southwest of Ceylon.

When the Japanese were at their most vulnerable, they would coordinate a strike with Royal Air Force units on the island to overwhelm and destroy the Japanese fleet. On paper, the British Eastern Fleet was formidable, consisting of three carriers, five battleships, seven cruisers, and fourteen destroyers based out of Ceylon. Closer examination revealed significant limitations. Of the three carriers, two were modern fleet carriers, HMS Formidable and HMS Indomitable, although they operated mostly obsolete aircraft compared to the Japanese.

Between them, they carried forty-five Albacore torpedo bombers and thirty-three fighters. The third carrier, HMS Hermes, was Britain’s oldest and now obsolete. By the outbreak of war, she had been relegated to a training ship but was later recommissioned for frontline service. She could carry only seventeen obsolete biplanes and was too slow to keep up with the other two carriers.

Four of the five battleships were of the slow Revenge class, dating back to World War I. The only British battleship capable of keeping up with the two fleet carriers was HMS Warspite, an old but recently modernized battle cruiser. The British fleet carriers’ only advantages were armored flight decks and torpedo bomber squadrons trained for radar-assisted night attacks. Vice Admiral James Somerville had taken command of the Eastern Fleet the previous month and faced the problem of commanding a mix of modern and obsolete ships of varying speeds.

His solution was to split the fleet into a fast division, combining the two modern carriers with Warspite, and a slow division with Hermes and the four obsolete battleships. Allied codebreakers identified only two carriers in the Japanese force, which they expected to attack Ceylon on April 1. As a result, Somerville sailed early on March 30 from his base in the Maldives, anticipating an attack on April Fools’ Day. As planned, he placed his fleet in a patrol area one hundred miles southwest of Ceylon, expecting to engage an enemy force of a similar size to his own, and conducted aerial reconnaissance in the area where the Japanese were anticipated to approach for a strike on Colombo.

Ceylon’s air defenses went on high alert, and Catalina reconnaissance planes were launched to locate the approaching enemy fleet. Somerville, however, had been let down by his intelligence services. No sign of Japanese ships was detected by patrolling Catalinas or radio intercepts on April 1 or 2. Late on April 2, with some ships needing resupply, Somerville concluded that, as was often the case, the intelligence had made a mistake.

He detached Hermes and two heavy cruisers to resume previous commitments in the Bay of Bengal while he returned the rest of the fleet to Addu Atoll in the Maldives. Ceylon’s air defenses were stood down, but crucially, Catalina patrols continued. Although the intelligence proved mostly inaccurate, the Japanese were coming. With over three hundred aircraft, Vice Admiral Chuichi Nagumo’s five powerful carriers, all veterans of Pearl Harbor, stormed into the Indian Ocean, accompanied by four battleships, three cruisers, and eleven destroyers.

Only the Kaga was missing, having run aground and returned to Japan for repairs. After sweeping all before them in China and the Pacific, the carrier strike force, known in Japan as the Kido Butai, was at the peak of its combat power. Having not yet suffered the disasters of Midway and Guadalcanal, Nagumo’s task force was to launch a massive raid on Royal Navy bases in Ceylon, disrupt critical Indian Ocean convoy routes, and eliminate the British Eastern Fleet. Vice Admiral Jisaburo Ozawa’s separate task force, consisting of the light carrier Ryujo, seven cruisers, and eleven destroyers, collaborated with Nagumo by striking convoy routes in the Bay of Bengal.

Late in the afternoon of April 4, a Canadian Catalina flying boat spotted Nagumo’s fleet 360 miles southeast of Ceylon. The crew had enough time to report the location but not the size of the fleet before being shot down. Somerville had been caught in a bad tactical position, with the majority of his forces refueling six hundred miles away at Addu Atoll while Hermes and two heavy cruisers were in Ceylon. Somerville’s fully fueled fleet sailed for Ceylon at dawn on April 5, but it was too far away to impede the Japanese strike on Colombo.

Having lost the element of surprise after being spotted the day before, the Japanese realized they would not find the Royal Navy’s Eastern Fleet tied up in port as the Americans had been at Pearl Harbor. The Japanese sent in ninety-one dive bombers and thirty-six fighters led by Commander Mitsuo Fuchida, who had also spearheaded the Pearl Harbor attack. Due to delays in detecting the approaching strike, some Hurricanes were still taking off when the first Japanese fighters swept in over Ratmalana Air Base. Just seven Japanese aircraft failed to return to their carriers, while twenty of the forty-one defending fighters that managed to get airborne were destroyed.

Somerville, forewarned, took the precaution of dispersing the warships and merchant vessels gathered in Colombo’s harbors. The only Royal Navy ships left behind due to repairs were the destroyer Tenedos and the armed merchant cruiser Hector, both sunk along with a Norwegian merchant vessel. The Japanese bombers pounded Colombo, and while the explosions and fires looked spectacular, long-term damage was minimal. The heavy cruisers Dorsetshire and Cornwall had fled Colombo during the night to join Somerville’s fleet, which was rapidly approaching from the opposite direction.

The pair were racing southwest when they were spotted at ten in the morning by a spotter plane from the heavy cruiser Tone. Nagumo wanted those cruisers sunk, so he redirected eighty dive bombers intended for a planned second attack on Colombo to target the British ships instead. Dorsetshire and Cornwall were just seventy miles away from Somerville’s large fleet when the Japanese bombers appeared overhead. HMS Dorsetshire sank within eight minutes, leaving life rafts and wreckage behind.

HMS Cornwall fought back for twenty minutes before her stern rose high into the air and she slid to the bottom, her colors flying. Fuchida’s assessment of the one-sided engagement was harsh: “The surface vessels did not have a chance against our striking force. It was so easy. Sea power has changed and a new era has begun.

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Somerville suspected he was up against more carriers than he had been led to believe, based on signal intelligence and reports of the number of aircraft that had struck several targets. Mindful of the Admiralty’s directive to minimize risk to his fleet, Somerville turned south to widen his distance from the enemy. His plan was to avoid the Japanese fleet during the day before closing in at night to strike with radar-equipped Albacore torpedo bombers. That night, radar-equipped aircraft were launched in an attempt to locate the Japanese fleet but were unsuccessful due to Nagumo’s decision to head in the opposite direction.

Instead of capitalizing on his success in sinking the heavy cruisers by searching for the rest of the British fleet, Nagumo chose to circle back to the east of Ceylon in preparation for a strike on the naval base of Trincomalee. At naval headquarters, the Admiralty had now realized the magnitude of the naval force Somerville was up against. They sent a signal to the battle fleet: get out of danger at the earliest moment. Somerville decided to send the four old battleships to Mombasa, Kenya, while Warspite and the two fleet carriers would be stationed in Bombay, out of reach of Nagumo’s carriers.

After refueling at sea from his tankers, Nagumo struck again on April 9, this time at Ceylon’s other major port, Trincomalee. He dispatched ninety-one bombers and thirty-eight fighters to attack the port. A Catalina sighting report of the Kido Butai’s presence gave the British enough time to scatter shipping in the harbor and prepare for the incoming air strike. After receiving ample warning, seventeen Hurricanes and six Fulmars took position to contest the skies.

They shot down four aircraft but were soon overwhelmed by swarms of the faster and more agile Zeros, which shot down nine of the defending fighters. The air base and port were heavily damaged, though only one merchant ship was sunk in port. Later that morning, nine unescorted Blenheim high-level bombers evaded the combat air patrol to launch a surprise attack on Nagumo’s carriers. They scored no hits and were soon set upon by defending Zeros.

Only four returned to base, all damaged, although they did shoot down two of the Zeros. As Nagumo prepared his aircraft for a second strike at Trincomalee, a sighting report came in from a reconnaissance plane flying sixty-five miles down the coast from Trincomalee. A small aircraft carrier with two escorts had been spotted about five miles offshore. Nagumo shelved the port strike, and soon eighty-five dive bombers with nine escorting fighters were heading for the unfortunate ships.

The carrier was Hermes and her escort, the Australian destroyer Vampire, accompanied by the hospital ship Vita. Hermes had the distinction of being the world’s first ship designed as an aircraft carrier in 1918 and was important in the development of carrier warfare. Now obsolete, she was slow, and with no fighters assigned, her only air defense was three antiquated anti-aircraft guns. She was set upon by forty-five Val dive bombers, which ripped her apart in less than twenty minutes.

Although just as old, Vampire had been modernized and had a far more formidable air defense. She managed to hit one of her sixteen attackers before breaking in half and sinking ten minutes after Hermes. The remaining bombers uncharacteristically observed the Geneva Convention and left the hospital ship to pick up survivors, electing to hunt for other prey up and down the coast instead. They sank a corvette and three merchant ships before retiring.

Happy at bagging a carrier, Nagumo disengaged after recovering the strike and headed back to Japan. Japanese losses amounted to eighteen aircraft destroyed. While Nagumo kept the Eastern Fleet busy, Ozawa’s Malay force wreaked havoc off the Indian coast between Madras and Calcutta. To expand the coverage of his fleet, Ozawa divided his force into three separate groups.

Fearing air raids, the Royal Navy decided to evacuate the ports and disperse the merchant fleet, which played into Ozawa’s hand by increasing the number of targets at sea. In just three days, Ozawa’s force sank twenty-three merchant ships, weighing more than 112,000 tons. The only saving grace for the British was that Somerville had kept the Eastern Fleet relatively intact, thanks to Nagumo’s inadequacy and some luck rather than good judgment. The British feared that Japan would exploit its victory by invading Ceylon to control the Bay of Bengal and conduct air operations over southern India.

The raid demonstrated that if the Royal Navy were to challenge a Japanese carrier force, it would need to transfer most of its carriers from the Atlantic and Mediterranean theaters, where they were desperately needed. Within a few months, the United States Navy had solved the problem by destroying the Kido Butai at Midway and Guadalcanal. When four of the six fleet carriers the United States had started the war with were sunk, a grateful Royal Navy returned the favor by loaning the U. S.

Navy the fleet carrier HMS Robin.