Autopilot Flux Compass Location

Your thoughts please. I have to relocate my Raymarine autopilot flux compass because the current location is affected by where I store my new vacuum with its large motor.

A great location for it would be on a bulkhead that is about 6 inches aft of a 8D battery that is on the other side. I was wondering if the battery being within 6 inches of the compass would affect it?

Yeah, I know I could put the vacuum some other place but I don't want to.

Try putting a hand bearing compass in the location. If it reads roughly correctly at different points of the compass you know the area if free from magnetic anomalies.

The closer to roll centre of the boat the better.

6 inches from the battery is not likely to be practical. The battery is not a great problem, but the current in the wires leading to the battery is.

I think that location will be a problem as well. I had one about 3 feet from a set of battery cables adn when we would run the microwave (via the inverter), the boat would change heading by 5-10 deg.

Noelex said:

Try putting a hand bearing compass in the location. If it reads roughly correctly at different points of the compass you know the area if free from magnetic anomalies.

The closer to roll centre of the boat the better.

6 inches from the battery is not likely to be practical. The battery is not a great problem, but the current in the wires leading to the battery is.

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I did try a boy scout compass near the battery but it was very difficult to see any difference.

I should have mentioned that the battery is dedicated to the bow thruster and windlass so will never put out any current when the autopilot is in operation.

Thanks for the thoughts so far.

windmist said:

I should have mentioned that the battery is dedicated to the bow thruster and windlass so will never put out any current when the autopilot is in operation.

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That helps' but it will be receiving a charging current. Lead acid batteries take a long time to charge so there will be some current going into the batteries for some considerable time after the bow thruster/windlass is shut down.

This current will be much smaller than during operation, but the earths magnetic field is only weak.

It also sounds like it will be close to the bow thruster and windlass so this also needs to be taken into account.

Everything on a boat is a compromise, but it does not sound the ideal location

Low center of your boat if possible

I have seen them mounted on the pilot house sole, and believe it or not on the transom, At least three feet from magnetic influence.

Scary said:

I have seen them mounted on the pilot house sole, and believe it or not on the transom, At least three feet from magnetic influence.

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I thought about the pilot house sole too, but then I realized I wouldn't be able to wear my spurs. The little toot bucks like a bronco when it gets lumpy . . . . .

All kidding aside. The sole was too close to the engine below. I ended up mounting it on the bulkhead behind the helm seat, close to centerline and at about eye-level. Works very well there, even in the lumpy stuff.

Larry
M/V Boomarang