compass on steel boat

[ghostlymoron]

My mate John has a beatiful steel hulled boat - similar design to Suhaili (RKJ). Although he has had it in commission for 5 years he has not yet been able to sort out a working magnetic compass due to the hull material. Has anyone come up with a solution to this problem. John is planning to sail to the med next year - I think he should get a working compass first!

 

[Dipper]

You can buy compasses for steel boats which have adjustable compensators. To be accurate, you need to be competent at setting them up or employ a specialist to do the job for you (recommended).

For an example see page 48 of this catalogue . Warning - large pdf file!

 

[dsw]

i have a steel vessel and the golden rule is mount the compass away from any electrical wires.

 

[oldvarnish]

I've used compass adjusters (one in Falmouth and one in Lowestoft which you'll get from Google) and they're helpful chaps. Giv 'em a ring and do what they say

 

[homa]

A friend of mine had a steel boat with a TMC (Transmiting Magnetic Compass) mounted on the mast about 6 foot above the deck. He had a repeater in the cockpit.
It is quite possible to have a normal compass in the cockpit of a steel boat, but it requires proper compensation. I would recommend you contact a compass adjuster for advice before buying any expensive kit.

 

[RobBrown]

If he needs a compass adjuster & in the Solent, this guy did mine:

http://www.compassadjuster.co.uk/

Robinsons- nice guy & seems to know his business!

(No connection etc)

 

[kenp]

I bought a Silva compass designed for a steel boat. It looks like an ordinary compass except there are about eight large penny washers which you can either add or take away from each side to compensate for deviation. Price about 250 pounds six years ago.
I didnt have a clue about how to set it but was told by Silva it was as simple as stated above. I sited it on the cabin bulkhead in the cockpit. No matter how many washers I added or removed it didnt affect the reading which were way out on all points of the compass.
I re-sited it under the steel hatch left all the washers on and to my surprise found it quite accurate on most points of direction. I drew up a deviation card and now allow for a slight error on what ever point of sail im on.
I would suggest you try an ordinary compass in areas around the boat that suit being sited on, swing the boat and compare readings with a handheld compass. You might be pleased with the results and save a lot of money as well.

 

[KellysEye]

Three options:
1. use a professional
2. borrow a handheld fluxgate compass and work out the deviation yourself and keep a deviation card.
3. fit a fluxgate compass, which should have been done in the first place, and after fitting do 2 so that you have a backup

I've heard people say fluxgate compasses don't work in a steel boat, they are wrong - ours was specifically manufactured for American army tanks. The only requirement is the sensor should be mounted in the centre of the boat.

 

[dolphin]

http://www.fotothing.com/dolphin46/photo/baba22c069cb9115a097fa121e8cb6fc/

on the above page, we can see, how the compass need to be fit - as far as practicaly far from the steel !

re:adjusting (swinging) the compass
you can do this using a GPS, during swinging the boat in your area! need to know a magnetic deviation as the GPS will show you the TRUE course ! you need to calculate the magnet course( substruct or add the deviation) and use for adjusting the compass. first do, the main direction - N, S, E, W and after the others
do not forget to record the deviation results on each course !
hope this will help you
brgds