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Post by oceandiamond on Jul 15, 2013 7:58:47 GMT
Hi
Ocean Diamond is a 40 SO with a 56HP Yanmar. A strange thing has happened, now twice, will motoring downwind at cruising speed on autopilot ( Raymarine ) The boat suddenly does a full 360 with no instruction from me. Very disconcerting. Has anyone ever come across this before ??
On another question. What should the typical consumption be for a Yanmar 56HP running at 2500/2700 revs ?
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Post by Trevor on Jul 15, 2013 11:27:58 GMT
Hello oceandiamond,
I have had a strange experience with a previous yacht where the autopilot was very confused and showed our yacht travelling backwards in the right direction but we were actually travelling forwards.
The problem was caused by me putting our vacuum cleaner in a cupboard up against the flux gate compass. As soon as it was removed, the problem was resolved. The magnetic field of the electric motor certainly confused the compass. I should have known better than to put the device close to the fluxgate compass but simply put it in the cupboard and unfortunately the compass was mounted pretty low in the cupboard.
In the first instance I suggest checking around the fluxgate compass in trying to resolve this issue. Sorry, I am not sure about the fuel consumption.
Regards and good luck,
Trevor
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Post by Tafika II on Jul 15, 2013 15:42:31 GMT
We had a similar problem when we 1st commissioned the boat. Coming back from Mexico to CA the AP would not hold a course and would make wild swings. In our case it was a bad flux gate compass, so your's may have failed or is being interfered with from some other object.
Good luck tracking this down!
Brent
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Post by touchngo on Jul 16, 2013 7:11:05 GMT
..... On another question. What should the typical consumption be for a Yanmar 56HP running at 2500/2700 revs ?...... We typically run at these rev's, giving a motoring speed in light winds of around 6 to 6.5 knots, and a consumption of around 2.5 Litres an hour. These are rough values based on the last 4 years of cruising in the Eastern Med, and it does obviously vary with windspeeds, current, and some times just running the engine for a bit on the hook etc... Hope this helps. No idea on the autohelm issue as ours has never done this at all. Cheers, PT |
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Post by Full Circle on Jul 16, 2013 20:55:25 GMT
When you have moved all of the potential interferences out of the way, there is a quick, easy check of the fluxgate compass, on the Raymarine website. All you need is (a small screwdriver and) a multimeter. www.raymarine.co.uk/knowledgebase/index.cfm?view=3798Will take about 10 minutes. |
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