A fascinating read and it looks like we were lucky not to lose more.
https://www.usni.org/magazines/naval...ol-during-1982
The San Luis began her patrol with the intention of striking the task force north of the Falkland Islands. During her one continuous patrol she claimed three torpedo attacks against British shipping. She claimed to have fired two German-manufactured SST-4 antisurface ship torpedoes and one American Mark 37 antisubmarine torpedo. Her first engagement was against HMS Yarmouth (Type 12 frigate) and HMS Brilliant (Type 22 frigate).
The San Luis’ attack did not result in any hits and she sustained a determined ASW battle for 20 hours, surviving depth charges and one torpedo. The San Luis broke contact and began her second run on 8 May against a British submarine. Twelve minutes after firing her torpedo, the San Luis heard an explosion from her target’s same bearing; however, the Royal Navy claimed no losses of any submarines during the conflict, and it is speculated that the San Luis’ torpedo may have struck the bottom.
Her final run was conducted on 10 May against two more warships, firing one torpedo against HMS Arrow (Type 21 frigate) and HMS Alacrity (Type 21 frigate). After six minutes, a small explosion was heard on the frigate’s bearing, and when HMS Arrow retrieved her towed countermeasure, it was evident that she had been hit.
The main British Task Force was located and attacked without success by the Type 209, San Luis. That submarine was at sea, and at times in the area of the British force, for an estimated 36 days. The threat from Argentine submarines was a continuous concern for the British Task Force commander, and numerous attacks were made against suspected submarine contacts, with a large number of ASW weapons being expended. In any event, San Luis survived all British ASW efforts, but at the same time was unable to inflict damage on the British force because of materiel problems.”
The submarine has been identified as firing its munitions too deep, having an outdated fire-control system that required the crew to calculate their solutions manually; broken wires after the torpedoes were fired, which denied the ability to steer the fish to their targets; lack of preparation of the SST-4s in the torpedo room’s tubes; which did not allow the torpedoes to arm themselves after firing, and an inexperienced crew.5 All these factors combined to allow the targeted ships to escape the San Luis’ attacks.
The attacks were poor, but the fact that the San Luis could make these approaches against the best of the Royal Navy shows how different the outcome could have been if the San Luis had been fully provisioned and prepared for combat operations.
It is significant, however, that these attacks and ASW battles took place. A German designed and manufactured U-boat had fired live torpedoes in anger against warships of her majesty’s Royal Navy for the third time in the Atlantic during the 20th century. This time, the submariners in this Latin American version of Das Boot had encountered a stroke of luck as they managed to slip past the Royal Navy’s determined depth charge and torpedo attacks and returned home without a scratch.
More though we maybe cannot access them.
https://www.usni.org/magazines/proce...edge-falklands
https://www.usni.org/magazines/proce...-falklands-war
https://www.usni.org/magazines/naval...ding-falklands