From:	Peter Coxon <coxoff@***.COM>
Subject:	Re: 2000 Leagues V1.2
Date:	Thu, 31 Oct 1996 20:43:29 UT

>|>Why Radar instead of Sonar? And, it's a whole lot easier
>|>to wire-guide the torpedo to the target that's been
>|>identified by the system (and cheaper, you don't waste
>|>money on a guidance system in the torpedo itself).
>|>
>|>And, I'm not sure though, ultra sound has pretty piss poor
>|>range underwater (or maybe short range resolution).
>
>|Okay, What is the definitive long range high quality under water system,
>|idea's? Ultra sound doesn't seem to be too popular, Radar in the above
article
>|was just me taking the longest range painter from FOF and bunging it in
>|there...with 1/10th range....
>
>Active sonar is works almost the same as radar. It sends out a wave of
>sound and the sound reflects off of targets. Then you do some math and you
>know where everything is. It gets a little more complicated when you start
>taking into account temperature differences in water and some wierd
>reflections that can occur. Unless you really know a lot about sonar I
>wouldn't worry about it too much.
>
>Passive sonar is a misnomer. There is no sonar involved. You have
>accoustic sensors that listen for noise. The sensitivity of the sensors
>and the filtering abilities of the system program decide what you can and
>cannot hear (and it also depends on how quiet the other guy is). And
>temperature differences play a big part. If something is under a
>temperature differential the differential can block or muffle sound.
>
>And, if you're using active sonar and the other guy has passive sensors,
>he'll know exactly where you are.
>
>And torpedoes launched from subs have a minimum range. Well, actually the
>torpedoes are set *not* to detonate within a certain distance of the sub
>that fired them (because the force of shock wave travels pretty far). This
>can be disabled though.
>
>And there are two types of torpedoes. Wire guided torpedoes are controled
>by the sub that launched them. Other torpedoes have their own sonar and
>seeking software (and they do not discriminate, if they lose their target
>they start circling and go after the first thing they find). And fast
>torpedoes make a lot of noise. But if you're really sneaky you'll find
>your target with passive, send a nice slow (quiet) wire guided torpedoe at
>him, and take him out without him even knowing what happened.
>
>|Ps. Thnax for the quick reply, it's currently 5:22PM here and I check my
email
>|every hour aprx.
>
>I get bored at work too :)
>
>-David
>
Groovy, So there is active and passive sonar, what is the range of the active
sonar?
-Tim