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From: lavida (no email)
Date: Thu Jun 01 2006 - 20:41:52 EDT
Perhaps infrared detection??
-----Original Message-----
From:
[mailto:] On Behalf Of Ken James
Sent: Thursday, June 01, 2006 7:09 PM
To: ; Philip
Subject: Re: lv-ab: "Prper Watch"
As far as watch keeping aids are concerned I would think that a passive
sonar unit would be just the ticket. Sound travels faster and further
underwater than in the air and a ship of fishing vessel would be audible
for some distance.
Any one hear of such a thing for small boats?
Reply;
In fact, at one time I had a financial backer who was interested in just
such a device. However I am convinced it is a very tough technical
problem if you use just one mic or sensor. This is because sound is
distorted so much through water, you may hear a ship 20 nm away clearly
but not the one right next to you. An array of sensors at different
depths would be needed.
Or it may be possible to link a net of sensors electronically.
I also served in the USN on Destroyers. One of our main jobs was hunting
subs. Our sonar was state of the art, but when it came to detecting
surface ships, it was nowhere near reliable, it would sooner or later
but when was a question and getting accurate range could be a problem.
Of course the same was true for subs, even though the sonar dome had
many sensors. But we did a search pattern and did it over and over if
necessary, as well as deploying both radio drop sones from a helo that
would go to different depts and towing a powerful array at different
depths. With all of that in action and also links to other ships and
underwater listening stations we could detect subs before they could
detect us...most of the time.
Of course a sailboat can't do all that. So in other words yes it could
be done but the answer is not simple or cheap.-Ken
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