This may be an incredibly stupid question, but I know they used gravimeters to map the ocean floor on subs.
And I recall an anecdote of snow fall on a roof effecting their results in a lab, could you possibly use them to detect other subs.
And I recall an anecdote of snow fall on a roof effecting their results in a lab, could you possibly use them to detect other subs.
[0] Err, almost. There is no such thing as perfectly neutral buoyancy. In practice, they are very slightly heavy and fly though the water as a lifting body.