Currently in the news is the search for the Argentinian Submarine, ARA San Juan (S-21), which has been missing in the South Atlantic for the past 6 days. With 44 crew onboard, there is a joint operation to locate, and rescue those trapped. Britain has sent HMS Protector, an Ice Patrol Ship (A173) to assist in the search, and an aircraft is on stand-by should it be required.
Back in the day, when I served in the Royal Navy, one of my drafts was to ARE Helston (Admiralty Research Establishment); and one of my roles there was to operate the navy's only Submarine Rescue Unit. I am unsure if the unit still exists, or whether it has become part of the many cut-backs over the years; but back then, our unit consisted of 4 staff. We operated a SCORPIO ROV (Remotely Operated Vehicle) which was similar to an underwater robot. Unmanned, it was operated from the surface via an umbilical cable. With manipulator arms, cutter attachments, sonar systems, and cameras/lights; it was designed to locate the wreck of a submarine, survey it for damage or signs of life, and then deploy air canisters in order to feed air to those trapped inside.
Often, we were under-utilised as there were very few actual submarine rescues to perform. We trained so that we would be available at a moment's notice, but quite a lot of the time, we were deployed (hired-out) to companies like BT to assist in the survey of their underwater cables and pipework.
By doing this, we often worked closely with their civilian crews who operated a manned mini-sub, which was also used in the event of a real rescue. This mini-sub had an open moon-pool in the center of the hull, through which submariners could escape their sunken coffin once the sub had coupled to the escape hatch. If you watch the film, "The Hunt For Red October" it will give you a good idea of its capabilities.
Whether these units are available now, to be used in this case, I do not know. I am sure the US navy have similar capabilities and will deploy them to the scene.
But at the moment, it is irrelevant. The weather conditions are far too rough to deploy an ROV or a Mini-sub, with huge waves in excess of 5m in height. Additionally, you can only deploy ONCE the submarine has been located; as it stands, this has not been achieved (again, due to the weather conditions).
Current weather conditions video:
To read more about my service with the UK's Submarine Rescue Unit read my book:-
"Beyond the Waves: My Royal Navy Adventures"
Available from Amazon worldwide.
Click HERE.