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From: greg@ncelvax.UUCP (Gregory K. Ramsey)
Newsgroups: sci.military
Subject: Re: mines
Summary: Ship Degaussing
Message-ID: <11668@cbnews.ATT.COM>
Date: 22 Nov 89 17:12:17 GMT
References: <11549@cbnews.ATT.COM> <11600@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Organization: Naval Civil Engineering Lab, Port Hueneme
Lines: 46
Approved: military@att.att.com



From: greg@ncelvax.UUCP (Gregory K. Ramsey)
In article <11600@cbnews.ATT.COM>, oakhill!serval!seningen@cs.utexas.edu (Michael Seningen) writes:
> 
> 
> From: oakhill!serval!seningen@cs.utexas.edu (Michael Seningen)
> An interesting counter-measure was to run a wire or seri
> es of wires around the hull (i'm not kidding) and set up
>  an electric field of just the right value such that its
>  corresponding magnetic field (which is 90 degrees wrt th
> e electric field) that cancels the hull effect on the ear
> ths magnetic field.
> 
The Degaussing or deperming of Navy ships is of no small
importance to the US Navy.  All Navy ships (at least those
considered "combat ships") are depermined soon after they are
commissioned and after major overhauls.  Depermining involves
measuring the ships magnetic flux and then taking the ship to
a facility where they wrap huge cables clear around the ship
making a huge coil.  This is a huge all hands effort on a
destroyer (all hands on my last ship included all but the CO and
XO), I shudder to think what is like on a carrier. (I've only
seen pictures of that)  Then the cables are charged in
somesort of pattern.  The intent is to reduce the ships normal
field as much as possible.

Then as Michael said, their are permanent cables wrapped around
the inside the ship around each of the 3 axis (x,y,z).  These
can be energized by equipment on board the ship.  The purpose
is of course to nuetralize the ships field.

These charges will be adjusted depending on a number of
factors including the ships position relative the earth's
magnetic fields, it's course and speed.

And then you can multiply the complexity probably 10x if the
ship is a minesweeper.

Greg

-- 
 greg@ncelvax.uucp ___             Greg Ramsey                    
         _n_n_n____i_i ________    Naval Civil Engineering Lab
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