Comment by ethbr0
3 years ago
Sonar beacon. Radio is useless underwater.
It reportedly has radar reflectors and radio, for when it's on the surface.
At 3800 m+ underwater, it'd need to be a powerful beacon. Even most military sonar maxes out around half that.
It's possible that it's floating just under the surface, in which case the radar reflectors won't help. Radar also isn't necessarily _great_ at finding anything bobbing in waves, as water will itself reflect radar.
Additionally, if the problem was a power outage then the radio also might not work unless it had a separate power supply.
Emergency beacons cost a few hundred dollars and are designed for this purpose, not having one is pure negligence.
If they're on the bottom of the ocean then even if they're found a rescue is unlikely to happen in time.
Couldn't you have a beacon that detaches from the vehicle, floats up to the surface and transmits the signal from there?
AKA an EPIRB: https://en.wikipedia.org/wiki/Emergency_position-indicating_...
You can buy one for a few hundred bucks, but based on everything I've read about this outfit so far, I'd be surprised if they even had that.
You'd need to carry 4km of cable with you