An Argentine submarine, the ARA San Juan, is missing in the South Atlantic Ocean.
The crew of 44 has been out of contact with the Argentine Navy for 48 hours.
While it may simply be a communications problem that does not pose a threat to the boat, if there is a risk to life here, the British Navy is well-placed to help out. The map below shows the San Juan's likely northward route to its home port at Mar del Plata and the proximity of that route to the British Falkland Islands.
That proximity is relevant in that, since its 1982 war with Argentina over ownership of the Falkland Islands, Britain has retained a considerable military presence to defend the islands. This involves a constant deployment of Royal Navy surface vessels and the semi-regular deployment of British submarines.
Considering that the U.K. government has offered assistance to Argentina's search efforts, Royal Navy submarines would be most useful.
After all, those boats are equipped with advanced sonar systems the Argentine Navy lacks. I believe all of Britain's in service Astute-class and Trafalgar-class attack submarines are fitted with the Thales 2076 sonar system, a highly advanced integrated passive/active sensor platform that basically turns its submarine carriers into underwater spy satellites. And while the newer Astute-class boats are likely to have the most advanced 2076 systems, any variant should be exceptionally capable in helping to find the San Juan.
Indeed, the Royal Navy might already have an idea of where the San Juan is. That's because any U.K. submarines in proximity to the Falkland Islands likely would have tracked the San Juan's movements for reasons of training and security.
Regardless, with San Juan over 30 years old, the 2076 system has a good chance of finding it. While Argentinian coastal waters are relatively shallow, even if the San Juan is not moving, Argentina's publication of the boat's origin and intended destination means that 2076 active sensors should be able to find it.
Submariners do immensely complex and courageous work, so let us hope for the best.