[107628] in Cypherpunks
Re: [Fwd: C-Subs, a very scary thought]
daemon@ATHENA.MIT.EDU (Michael Motyka)
Tue Jan 19 22:07:27 1999
Date: Tue, 19 Jan 1999 18:54:15 -0800
From: Michael Motyka <mmotyka@lsil.com>
To: cypherpunks@cyberpass.net
Reply-To: Michael Motyka <mmotyka@lsil.com>
>> Concrete would not show up on sonar displays (it looks just like sand
>> or rocks), so the passing ships would not see the sub lurking below.
>>
The only things that won't show up on sonar would be water ( at the same
temp and of the same composition as the surrounding volume ) or another
material that matches the water's impedance exactly in the required
band. Otherwise you get a reflection. Concrete doesn't fall into ether
of these categories.
> As long as the sub is in the bottom this may be true.
>
Not so. A scan of the bottom that showed a 1/4 mile long, 30 ft diameter
cylindrical object resting on the bottom would probably raise some
eyebrows. I wouldn't be surprised if this sort of sonar is standard
equipment on many Naval surface ships. The sonar is probably described
somewhere in the Wassenar agreement under direction of transmission,
power density ( depth capability ), frequency and aperture ( resolution
), and signal processing capabilities.
Remember how debris from plane crashes is located? Much of it is a lot
smaller than a submarine.
Not to mention any sort of comm or sonar emanating from the thing.
Aren't $$$ and magnetic detection methods the only issues a concrete sub
really addresses?
Mike
