Compass adjustment

[Guest]

Anyone know how to set up a compass? I had a bash at my Plastimo and now it's way out!! It has two adjusting rods at right angles, but I'm bu..ered if I can get it sorted...

Thanks in advance.

 

[Piers]

Compass adjusting is an art, and complex to say the least. Years ago, I was a licenced adjuster, but have long forgotten the process!

Try calling the professional compass adjuster I now use - 02380 453533

Piers du Pré
MBM Cruising Club enthusiast
www.dupre.co.uk

 

[neale]

Well I never knew that!

Neale

 

[LORDNELSON]

I agree; last year my compass was very well cleaned and repaired by Mr. Muir, Southampton, 0238 0261042, very reasonably. At the time he quoted a reasonable figure for swinnging my compass near Hamble. I hope to have this done soon

 

[ianwright]

To go sailing between now and the visit of the Pro, take out the rods and keep them safe off the boat. Chances are the compass will not be far out.
Anyway try it and do a quick swing to check.

IanW

Vertue 203, Patience

 

[Chris_Stannard]

First stage is to swing your compass. If you have not done it before you need calm water, and hand bearing compass and someone to write down for you.
Make sure the hand bearing compass is okay by checking it on a known transit. You also MUST make sure your ship's head is correctly lined up.
Starting on a convenient Cardinal (N,E,S or W)s steady on courses at 30degree intervals by the hand compass and noting the heaading by the steering compass. If the reading are within aa reasonable margin do not go farther.
If the readings are to far out, you should find that you have a bias, say easterly on both North and South. This can be corrected by steering North and using the North correction (the one in the athwartships position). You really need a non magnetic screw driver to do this. Similarly if you have a northerly or southerly bias on easst west you steer east or west and correct using the east/west correctors, which are fore and aft.
WARNING WORDS - If you are regularly going across the channel or farther 1degree of error gives you one mile of error in 60 miles - the distance from the Needles to Cherbourg. So if in doubt get it done by a professional, it helps for the peace of mind.
FINALLY - I bought a new plastimo compass and the correcting magnets had been mounted the wrong way round, that took an expert to find