Perhaps the real success of the Argentine submarine campaign was that it forced us to counter it. Numerous Sea Kings, and the odd Wessex, were required to maintain a constant screen around the carrier task force, while others had to be detached from the main force to escort ships in and out of Falkland Sound. The logistic tail required for this was huge, and the Sea Kings took up valuable capacity on the carriers.
The Argentine submarines' mere existence was enough to cause us problems. In terms of Naval warfare, a small conventional submarine must be one of the most cost-effective weapons available.