re: Titanic tourist submarine goes missing

Not much technical data on their web site. The CBS news video posted earlier mentioned the owner (?) stating the sub was not certified by any regulatory agency such as ABS, Lloyds or DNV.

The sub was reportedly navigated to location from the surface ship using USBL acoustics, aided perhaps by Inertial Nav on the sub itself. The brief footage of this indicated a Sonardyne USBL system in use. For professionals a relatively easy navigation task using an excellent system they have onboard the sub and support vessel.

The Titanic site is very quiet acoustically, about 45 db background acoustic noise. USBL acoustic tracking would be robust and trivial. For comparison, the Gulf of Mexico “averages” 70 to 80 db, logarithmic, mainly from all the O&G and concentrated ship activity. Halfway to Mexico from say Venice it becomes quieter.

If they’ve lost USBL tracking and voice and text comms, my guess is they’ve lost the sub. There’s no rescue assets nearby I’m aware of that could arrive within the 96 hour life support window, if stranded on bottom.