May 2 marks the fortieth anniversary of the first and only sinking of a warship by a nuclear submarine. By successfully sinking the Armada de la República Argentina’s (ARA) light cruiser, the ARA General Belgrano, the Royal Navy’s HMS Conqueror had greatly aided the British in recapturing the Falkland Islands during the 1982 Falklands War. After General Belgrano was sunk, the entire Argentine Navy returned to port and never again ventured out to threaten British naval forces.

“The sinking of the Belgrano turned out to be one of the most decisive military actions of the war,” British prime minister Margaret Thatcher remarked at the time. Indeed, with this lone submarine action, British forces successfully gained sea control around the Falkland Islands.

The story begins on April 2, 1982, when Argentina, which had long demanded the return of the Falkland Islands from the British, launched an amphibious assault and captured the Falkland Islands. In response, the British quickly assembled a naval task force to retake the islands. A number of British nuclear hunter-killer submarines including the HMS Conqueror were also dispatched immediately to the Falkland Islands to conduct advance reconnaissance and combat patrols.

The British had also declared a Maritime Exclusion Zone (MEZ) of 200 nautical miles around the Falkland Islands, threatening to attack any Argentine warship entering the MEZ. The Argentines were aware of the British naval task force heading towards the Falkland Islands and sent three naval groups to intercept the British naval fleet sailing towards the MEZ after diplomatic efforts to end the conflict proved futile.

The first naval group consisted of the Argentine Navy’s sole aircraft carrier, the ARA Veinticinco de Mayo; two Type 42 destroyers; and three corvettes. This naval group caused considerable alarm for the British, and submarines including the HMS Conqueror were sent to hunt and attempt to sink the Argentine aircraft carrier. The aircraft carrier was equipped with A-4Q Skyhawks naval attack aircraft that could cause extensive damage to the British fleet and seriously degrade the British’s chances of launching a successful amphibious assault on Falkland Islands. The second Argentine naval group consisted of a World War II-era light cruiser, the ARA General Belgrano; two World War II-era destroyers; and a fuel tanker. The third naval group consisted of three corvettes equipped with Exocet anti-ship missiles.

As the British fleet sailed closer to the Falkland Islands, there was immense pressure for the Royal Navy submarines to detect and sink the Argentine ships. The second naval group led by ARA General Belgrano was found by HMS Conqueror on April 30 which tailed the Argentine naval group from a distance. As the light cruiser was not operating sonar equipment, its crew were not aware of the presence of HMS Conqueror shadowing it. The first Argentine naval group with the aircraft carrier was also detected by HMS Splendid, but due to rough weather conditions, it soon lost track of the Argentine aircraft carrier.

By now, the British war planners in London were extremely worried about the threat posed by the Argentine naval groups on the British naval task force. Thatcher knew that the stretched lines of logistics—the Falkland Islands are 8,000 miles from the British Isles—meant that any sinking British ships, especially its two valuable aircraft carriers and the vulnerable troop transport ships, would result in huge losses of lives and combat capabilities, and may turn public opinion against any continuation of hostilities, resulting in the permanent loss of the Falkland Islands to Argentina.

The British had also intercepted a message to the Argentine naval groups on May 1 ordering them to advance towards the British fleet to conduct a pincer attack, one from the northeast and the other from the southwest of the Falkland Islands. Based on this new intelligence report, HMS Conqueror was given the order to attack and sink the ARA General Belgrano.

HMS Conqueror fired three torpedoes at ARA General Belgrano on the evening of May 2. HMS Conqueror had used World War II-era MK8 torpedoes as opposed to the more modern Mark 24 Tigerfish homing torpedoes as the submariners decided that the MK8 was more reliable—ironically, WWII-era torpedoes for WWII-era targets. Two of the torpedoes hit ARA General Belgrano and the third allegedly hit an escorting destroyer but did not explode. The torpedoes tore two holes in the ARA General Belgrano, sinking it in just a few minutes and killing more than 300 Argentine sailors out of slightly more than 1,000 total onboard.

The sinking of ARA General Belgrano rattled the nerves of the Argentine naval groups, which, realizing the dangers and the vulnerabilities of their surface ships against advanced British nuclear submarines, decided to return to port, including the aircraft carrier ARA Veinticinco de Mayo. There would be no more attempts by the Argentine Navy to oppose or threaten the British naval task force which subsequently landed successfully on the Falkland Islands on May 21.

The Argentines were forced to use their airpower to oppose the British fleet, but the more than 400 nautical miles from their air bases on the Argentine mainland to the Falkland Islands limited their aircraft’s operational endurance. The extreme range constrained the aircrafts’ loitering time to a few minutes to locate and conduct air strikes against the British naval task force. The retreat of Argentina’s naval forces also inevitably resulted in terminating the resupplying of its forces on the Falkland Islands by sea, contributing to severe logistics support problems.

This single submarine action by HMS Conqueror, the first and only torpedo sinking of an enemy combat ship by a nuclear submarine, managed to deter and deny the Argentine Navy from threatening the British naval task force. HMS Conqueror’s performance demonstrated the value of nuclear-powered hunter-killer submarines. With the capability to travel at high underwater speeds with a long underwater endurance and large operational radius, nuclear hunter-killer submarines continue to be a prized strategic asset today.

Dr. Adam Leong Kok Wey is professor of strategic studies, and the Director of the Centre for Defence and International Security Studies (CDISS) at the National Defence University of Malaysia (NDUM). His latest book is Strategy and Special Operations: Eastern and Western Perspectives published by NDUM Press (2021).

Image: Wikipedia.