Julian wrote:
"Armond Perretta" wrote ...

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

... for boats
with the power to keep it running, it would be very interesting
technology. The obvious use is for single-handers but, even for
crews maintaining a 24 hour watch, humans can get tired and have
lapses of concentration so an extra "safety net" would be very
useful.

I have many times, in clear conditions and with "unlimited" visibility, had
the radar pick up targets that I probably would have missed using only
binoculars and a steady hand (even assuming that I was at the time being
diligent). I am not suggesting that one should rely _only_ on electronic
aids, but if they can be supported financially, maintenance-wise, and
power-wise, I think the decision gets fairly obvious.

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