[107653] in Cypherpunks
Re: CDR: Re: [Fwd: C-Subs, a very scary thought] (fwd)
daemon@ATHENA.MIT.EDU (Mark Hahn)
Wed Jan 20 11:37:46 1999
Date: Wed, 20 Jan 1999 11:04:23 -0600
To: Jim Choate <ravage@einstein.ssz.com>, cypherpunks@einstein.ssz.com
From: Mark Hahn <MHahn@tcbtech.com>
In-Reply-To: <199901201310.HAA03012@einstein.ssz.com>
Reply-To: Mark Hahn <MHahn@tcbtech.com>
At 07:10 AM 1/20/99 -0600, Jim Choate wrote:
> > Date: Wed, 20 Jan 1999 00:33:06 -0800
> > From: Tim May <tcmay@got.net>
> > ...
> > Not that steel vs. concrete has anything to do with showing up on sonar:
> > ...
> ...
>As to a new set of laws, of course not. But since concrete is basicaly sand
>and gypsum with a handful of other materials it makes sense that they will
>be harder to pull out of the grass since their basic constituents, and by
>extension their sonar reflective properties, will be similar.
>
>It's the same old physics: density, reflection, refraction, diffraction.
> ...
Sonar is mostly about reflection. Concrete or metal, it will reflect a sound
wave. As to whether or not you can tell if the reflected sound wave was
reflected off of metal or concrete (rock like stuff), I don't think it effects
the interpretation. I don't believe a USN sonar is going to disregard
a large "rock" floating 200 feet above the ocean floor.
Or, if the sonar is that sensitive, and the hiding submarine is sitting on
the floor, it will look like a suspiciously long, cylindrical "rock".
I would suspect disguising your vessel to sonar is more difficult than
disguising your self to radar.
But then we should be asking someone with a background in sonar
and not just guessing ;-)
-MpH
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