To Lemain:
I recognize sea water has sharp salinity and temperature differences, but am very skeptical that an object would just accidentally achieve such a fine tuned buoyancy as to make that relevant. It sure does not work for submarines, even though they have every incentive to make it happen.
To Airlandseaman:
I'd thought that the RAT would provide enough power to maintain wings level flight. Your simulator reference suggests that this is incorrect.
That seems a very material insight. Thank you for clarifying this issue.