HMS Hermes holds a specific place in naval history. She was the world's first purpose-built aircraft carrier to enter service with the Royal Navy, and she became the first fleet carrier in history to be sunk by carrier-based aircraft. Both facts happened within 20 years of each other. The second happened in Trincomalee Bay.
Design and construction. Hermes was laid down at Armstrong Whitworth's yard on the River Tyne in 1918, before the Washington Naval Treaty of 1922 that limited carrier tonnage across major powers. She was designed from the keel up as a carrier, unlike predecessors which were converted battlecruisers and cruisers. She displaced 10,850 tonnes, stretched 182 metres in length, and was built to carry 20 aircraft. By the standards of the 1920s, she was a modern ship. By 1941, she was obsolete: too small and too slow to operate modern strike aircraft effectively.
Service history. Hermes commissioned in 1924. She served in the Atlantic, the China Station, and the Mediterranean. By 1939, as war began, she was operating in an escort and convoy protection role rather than as a strike carrier. Her airwing was too small and her aircraft too dated for front-line fleet work. In 1942, she was based at Trincomalee as part of the Eastern Fleet.
The Battle of Ceylon, April 1942. Japan's Indian Ocean Raid, Operation C, was one of the most ambitious carrier operations in the war. Vice Admiral Nagumo led a force including the carriers Akagi, Hiryu, Soryu, Zuikaku, and Shokaku, the same carriers that had attacked Pearl Harbor four months earlier. The objective was to destroy British naval power in the Indian Ocean.
On 9 April 1942, intelligence indicated an attack on Trincomalee was imminent. The Eastern Fleet had already evacuated to safer waters. Hermes, with HMS Vampire (an escort destroyer) and several other vessels, was ordered to withdraw. She was caught at sea, 10 nautical miles south of Trincomalee, without her aircraft embarked. They had been sent ashore for safety the night before.
Nagumo's dive bombers, Aichi D3A Val aircraft from Akagi and Hiryu, found Hermes shortly after 10:00 local time. Without air cover and with only anti-aircraft guns, she had no defence against a coordinated dive-bomber attack from 70 aircraft. She took 40 direct hits in under 10 minutes. At 10:55, she rolled over and sank. Of her crew of 590, 307 were lost. HMS Vampire sank minutes later.
Historical significance. Before this engagement, naval doctrine held that well-defended capital ships and carriers could repel air attack. The sinking of HMS Hermes proved otherwise. It confirmed, following the loss of HMS Prince of Wales and Repulse to land-based bombers in December 1941, that the era of the battleship as the supreme naval weapon was over. Aircraft carriers would dominate naval warfare from that point forward.
Discovery and diving. Hermes was located by divers in the 1990s and confirmed through survey diving. She lies on her starboard side, largely intact, in 27-52 metres. The flight deck, gun emplacements, and island structure are recognisable after 80 years. She has become one of Asia's most significant wreck dives, not for scale alone, but for the historical context she carries.
Today, diving HMS Hermes is a quiet, extraordinary experience. The ship sits in 35 metres of warm Sri Lankan water, covered in coral and surrounded by batfish. She is worth knowing before you dive her.