autopilots in steel yachts

[warby1212]

Just want to check with you learned, unbiased folk. Are there any difficulties using a tillerpilot (Raymarine, Autohelm etc) in a steel yacht, in regard to their built in fluxgate compasses.

Cheers stephen

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[PaulJ]

Stephen,

These tiller pilots have a self compensating programme though I am not sure what is the maximum deviation they can cope with. However it doesn't really matter since the autopilot only maintains a heading relative to the earth's magnetic field in it's own immediate locality. So you can press "auto" and it will maintain whatever heading you happened to be on at the time. The readout of the heading may not be correct but if you press "Minus 10" it will still turn to port by 10 degrees from whatever it thought it was on before.....

You may not be able to dial up a heading directly but having established a suitable course to steer from the GPS you will be able to press "Auto" on the tiller pilot and it will maintain that heading.

<hr width=100% size=1>I used to have an open mind but my brains kept falling out.....

 

[warby1212]

Thanks for the good explanation, makes a lot of sense. I didn't want to buy one and find it didn't work and have everyone say: "but everyone knows that..."
By the way have you tried earplugs?

Cheers stephen

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[snowleopard]

when you swing the autopilot compass it will build its own deviation table. you may have a bit of a problem with the change of magnetic field when heeling. the better autopilots will compensate for this.

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[peterb]

This doesn't always work. If you imagine a big bar magnet just under the autopilot compass, then you'll see that the compass would be showing almost the same field direction irrespective of the yacht's heading.

Most fluxgate compasses incorporate a method by which stray fields from the boat can be 'cancelled out'. But this is only possible to a limited extent, usually 15 - 20 degrees of deviation. My experience of steel boats suggests that you might expect considerably more than this at tiller level.

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