Thread by @ChrisO_wiki

1/ Here's a good trivia question: the apparent destruction by Ukraine of the Kilo-class submarine 'Rostov-on-Don' marks only the second time since World War II that a submarine has been confirmed lost due to enemy action in wartime. What was the first? Read on to find out. ⬇️

2/ Many submarines have been lost through accidents since the end of World War II. The United States lost 4, the USSR and Russia lost 18, and other countries lost a handful of vessels as well. But only one other country definitely lost one due to enemy action: Argentina.

3/ The submarine in question was the ARA Santa Fe, originally the US Navy's Balao-class diesel-electric submarine USS Catfish. Launched in November 1944, she was sold to Argentina in 1971. She was to become the last WWII-era submarine to be used in combat.

4/ Santa Fe and her sister vessel, ARA Santiago del Estero (ex-USS Chivo), served alongside new Type 209 submarines from West Germany. Both vessels were active during the Falklands War, but only Santa Fe participated in combat.

5/ On 2 April 1982, Santa Fe landed commandos on East Falkland near the islands' capital, Stanley. After returning to Argentina, she embarked on a second mission to the remote British island of South Georgia on 16 April, 1,541 km southeast of the Falklands.

6/ Despite her age and poor armament – twenty WWII-era Mk14 torpedoes and three modern Mk37s – she was tasked with transporting marines to South Georgia and then attacking the slower ships at the 'tail' of the British fleet in the South Atlantic.

7/ The vessel reached Grytviken, the only settlement on South Georgia, which Argentinian forces had seized on 3 April. Santa Fe unloaded the marines to reinforce the small Argentinian garrison there and set off back out to sea to find British ships to attack.

8/ However, she was detected by the sonar of the British destroyer HMS Antrim. A Wessex helicopter took off from the Antrim to find the submarine, which was travelling on the surface. The Wessex dropped two Mk.XI Mod3 depth charges, straddling Santa Fe.

9/ The explosions severely damaged Santa Fe, forcing her captain to turn around and head back to South Georgia. She could no longer submerge. The British continued pursuing the submarine, launching a Lynx ASW helicopter from HMS Brilliant armed with a Mk46 sonar-guided torpedo.

10/ Unluckily for the British, the torpedo had been designed to target deep-diving Soviet submarines; it had never been meant to target surfaced vessels and was programmed with a minimum depth. It could not lock onto Santa Fe and passed harmlessly underneath the vessel.

11/ The Lynx began strafing the submarine with its door-mounted machine gun, while Santa Fe's crew fired back from the vessel with their own small arms. Meanwhile, Wasp helicopters armed with with AS.12 air-to-surface missiles took off from HMS Plymouth and HMS Endurance.

12/ This time the British scored hits, achieving at least four and possibly five hits against Santa Fe's sail. However, the missiles had been designed to attack steel targets; the sail was merely fibreglass and light alloy. One missile went straight through without detonating.

13/ The other missiles did detonate, injuring a number of Santa Fe's crew, one seriously. The crippled submarine made it back to Grytviken but was immediately overtaken by the British recapture of the island on 25 April 1982. With no hope of escape, her captain surrendered.

14/ The British attempted to move the stricken submarine away from the quay to guard against the danger of an accidental detonation of her 23 torpedoes. However, Santa Fe partially sank and an Argentinian sailor, PO Felix Artuso, was shot dead by a British soldier.

15/ The vessel was eventually dragged into deeper water but then sank fully while under tow. She was raised in a risky and difficult operation in February 1985 but sank again under tow, going down 9 km off South Georgia in 358 m of water on 20 February.

16/ (Note: one other submarine was lost in a post-WWII war – the PNS Ghazi in the Indo-Pakistani war of 1965. However, the cause of its loss has never been clearly established, with India claiming to have sunk it and Pakistan claiming it to have been lost through accident.) /end