What is a " De gaussing " zone?

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dralex

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What is a \" De gaussing \" zone?

Just looking at the West Country Cruising guide and see there is one just off Plymouth near Rame Head. What is it?
 
Re: What is a \" De gaussing \" zone?

I think it is an area here ships are degaussed, ie have their magnetic signature removed as an attempt to thwart magnetic mines. I believe it is done with high current coils


Though I may be wrong

Regards
Cameron
 
Re: What is a \" De gaussing \" zone?

De gaussing is where you apply an AC magnetic field, by passing AC current through a big coil, in order to remove any permanent magnetism from iron. The navy use it to reduce the magnetic signature of their ships, to stop them setting off magnetic mines, to put it simply.
 
Re: What is a \" De gaussing \" zone?

The coils measure the magnetic signature of the vessel. What the "Grey funnel line" do is steam up and down over the range at a specific course and speed. The magnetic signature is read, and corrections can be applied on board.

There are lots of other things that are done as well. There is a gadget that measures the ship's pitch and roll (in the earth's magnetic field) and applies corrective currents to coils built into the ship. There is also corrections made for the course steered, as the ship is cutting more or less lines of magnetic force if it is going east-west or north-south.

Going on the DG range was a bit of a blo**y bore! Just steaming up and down all blo**y day!

It will cause you no harm whatsoever, as long as there is not some big grey ship around that may bump into you.
 
Re: What is a \" De gaussing \" zone?

yo,
just to reinforce what Jimi sez, theres a de gaussing element in all teles and monitors, theres one in front of you now, wont do you or your'e gera any harm........
 
Re: What is a \" De gaussing \" zone?

And there was me trying to be coy about the way it all works! Actually, the principle is still the same - but the kit has got a little more sophisticated.

One of the problems are what one might call 'ship awareness mines'. These detect what sort of a ship is passing over them and decide whether to blow up or not...
 
Re: What is a \" De gaussing \" zone?

We used to DG minewarfare vessels in the dock at Burnt Island(not sure if that's how it's spelt) They used to warp us out to the middle of the dock with big compressed air things strapped to either side of the old tub and spend all day pumping air from one to the other to rock the ship from side to side, while the DG wrens (as they were in them days) in the control room told the boffins on board which coils to tweak. It was incredibly boring and the noise as they pumped air from side to side 'orrible. I think I'd rather do it by steaming up and down a range.
 
Re: What is a \" De gaussing \" zone?

Jimirvine has got it right.
Sorry to correct Dave, but it is DC that is used in the ships De gaussing coils. AC would, as I know you will be aware, produce an alternating magnetic field.
Just to add a bit to other answers.
All ships have an inbuilt magnetic field which will vary with where they were built and the bearing on which the dock or slipway lies. This field will also vary with with lengthy dry docks and removals additions to the ships structure.
Passing a dc current through the coils arranged around he vessel will cancel out this field and hopefully, prevent the triggering of magnetic mines. The coils can vary from simple "M" coils which run fore and aft around the vessel and were normally fitted to merchant vessels, to extremely sophisticated arragements in "War canoes"
The ranges, sited at various places around the UK are used to measure the continuing effectivness and correct settings of the vessels installation and compute any adjustments that may be required.
As such they are "Passive" as far any other vessel is concerned. Unless of course you snag one with your anchor then you could receive a visit from some irate gentlemen!
 
Re: What is a \" De gaussing \" zone?

Yonks ago the old tankers that I sailed on had degaussing coils. There were 4 (I think) large rubber-sheathed cables clustered together that went round the whole ship. They were visible at the edge of the weather decks. There was a huge amount of copper in those cables and I was told that when one of those old ships was going to the breakers yard, the degaussing coils always 'disappeared' beforehand! Nice little earner- shame I was never in the right place at the right time! /forums/images/graemlins/frown.gif
 
Re: What is a \" De gaussing \" zone?

The fountain of knowledge erupts. Is ther anything the collective forum does not know? |thanks for the replies.
 
Re: What is a \" De gaussing \" zone?

I stand corrected, then. AC is what you use (for instance) to demagnetise (degauss) a permanent magnet or scramble a magnetic tape. For the younger readers, a magnetic tape is a prehistoric form of data and music storage. DC sets up a permanent magnetic field, which can be used to cancel out an inbuilt one, as long as its switched on, as you say. AC will scramble the magnetic domains in soft iron to minimise the permanent field, IIRC.
 
Re: What is a \" De gaussing \" zone?

When you get off Plymouth to the SW of the Western Channel you will easily see the range as it is well marked with yellow "special mark" buoys and each has a name clearly visible. These appear on the large scale charts
It might be worth remembering that you will be within the Dockyard Port of Plymouth and that the Act applies, but you will have no worries unless you see a great big grey ship hurtling up and down. In which case keep well clear.
 
Re: What is a \" De gaussing \" zone?

[ QUOTE ]
I stand corrected, then. .

[/ QUOTE ]

Likewise, didn't think of that sort of De-gaussing!

Just proves. "Every day's a school day"!
 
Re: What is a \" De gaussing \" zone?

in addition to de-gauzing coils on merchant and naval ships, 'flashing' a vessel was also done to smaller vessels, lasted about 6 - 12 months and dispensed with the need for heavy duty copper coils strung around a ship

/forums/images/graemlins/grin.gif
 
Call my Butt

harumph, the others are obviously having a laugh.

Gauss was famous mathematician and all-round clever dick, famous for doing nerdy stuff with compasses and a ruler, such as making complicated regular polygons and discovering various other stuff like binomial theorem. The "de-Gaussing" zone is simply an area of sea well-loved by the Navy navigators of olden days - safely back in the channel after months of tense navigational worrying they could relax at last- no more sodding Gaussian Mathematics. Beware of warships chucking rulers and compasses overboard or literally "de-Gaussing".

Hey- look it up - the magnetic stuff was done by Tesla, innit.
 
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