Vito wrote:
Armond Perretta wrote:

In any case a small sonar seems like a good possibility ...

Sound waves bend downward creating a blind zone near the surface.

Quite, but the sound waves generated by the target vessel do themselves
propagate in a uniform direction from the source, so they _will_ be picked
up.

--
Good luck and good sailing.
s/v Kerry Deare of Barnegat
http://kerrydeare.tripod.com