IIRC there have been cses where a released beacon has remained entangled in the sub and never made it to the surface....
This is not looking good
The Argentine navy says an event consistent with an explosion was recorded near where a submarine disappeared last week with 44 crew on board.
An "abnormal, singular, short, violent, non-nuclear event" had been detected in the south Atlantic, a spokesman said. The information came from an Austria-based anti-nuclear test watchdog, Capt Balbi said. It follows a report of a loud noise in the same area.
The new information was provided to the Argentine navy on Thursday by the Vienna-based Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Capt Balbi said.
In a statement, the CTBTO said two of its hydro-acoustic stations had detected a signal from an "underwater impulsive event".
On Wednesday the navy received a US report of a "hydro-acoustic anomaly" detected hours after the submarine went missing. Capt Balbi said the suspected explosion took place near the submarine's last known location. The navy only knew the location of the suspected explosion, not its cause, he said. Search efforts would be concentrated in the area, he said.