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.
What Went Wrong?
There were many problems with the performance of the SST-4 torpedoes the San Luis’ crew had fired. According to
a postwar analysis conducted by the U.S. Department of the Navy in September 1983:
"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The submarine has been identified as firing its munitions too deep, having an outdated fire-control system that required the crew to calculate their solutions manually; broken wires after the torpedoes were fired, which denied the ability to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.
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.