EV 100 autopilot wheel drive causing compass deviation

**groob32** · 28-10-19, 17:12

I have installed a new EV1, ACU100, P70 and wheeldrive as a replacement for an old ST4000 with a old black Mk 1 wheeldrive on my Jeanneau 32.2, and as an autopilot is is a big improvement. Unfortunately the compass (on top a standard binnacle) now has up to 18 degrees deviation (down from 30 or so before I repositoned the motor at the bottom of the wheel, slightly further from the compass). If I remove the wheel with drive and motor attached the deviation goes, so it seems it can only be the motor.
Raymarine have confimed that the new motor is more powerful but have not come up with anything more helpful. Is this something anyone else has encountered?

**Daverw** · 28-10-19, 18:54

More powerful mother =more magnets/copper, not sure raymarine can offer any advice anyway to sort. Big problem with probably no solution as it’s from below the compass so not rally able to compensate

**PaulRainbow** · 28-10-19, 18:59

Originally Posted by groob32

I have installed a new EV1, ACU100, P70 and wheeldrive as a replacement for an old ST4000 with a old black Mk 1 wheeldrive on my Jeanneau 32.2, and as an autopilot is is a big improvement. Unfortunately the compass (on top a standard binnacle) now has up to 18 degrees deviation (down from 30 or so before I repositoned the motor at the bottom of the wheel, slightly further from the compass). If I remove the wheel with drive and motor attached the deviation goes, so it seems it can only be the motor.
Raymarine have confimed that the new motor is more powerful but have not come up with anything more helpful. Is this something anyone else has encountered?

Yes, on a similar boat to yours. The boat in question belongs to a friend of mine, he removed the shielding from the old AP and fitted it to the new motor and the deviation vanished. Raymarine refuse to accept it's an issue, he's still waiting for them to get back to him, a year or so later.

**ctva** · 28-10-19, 19:23

I have the EV100 on a 34.2 and the compass is probably more off than yours. When you think about it today with all the electronics of displays, plotters, vhf mike, wheel pilot, phones etc., it’s no surprise.

I’ve not bothered with the binnacle compass for years.

As well as the wheel pilot compass displayed on the ST70, the chart plotter compass display (from a separate receiver),I also use a good hand bearing compass where I can step to the edge of the cockpit away from interference. There is no practical space on modern boats of our design and small space to have the compass in a neutral place that can also be seen by the helm. Even locating the wheel pilot compass was a challenge which I took a fair bit of effort to place correct distances from EM fields.

.

**groob32** · 29-10-19, 10:50

Thanks for that, guys, at least you've confirmed that (1) my probelm is not a one-off and (2) chasing Raymarine is likely to be a waste of time. Unless I get anywhere on the shielding route I'll just have to leave the cover on the compass!

FWIW, Chris, I installed my EV1 upside down in the plywood headlining over the rear berth, which seems to be OK.

**andygc** · 29-10-19, 16:04

Originally Posted by Daverw

More powerful mother =more magnets/copper, not sure raymarine can offer any advice anyway to sort. Big problem with probably no solution as it’s from below the compass so not rally able to compensate

I've had no problem compensating my compass. The error was about 12 degrees heading north or south and zero degrees heading east or west. I haven't done a precision job, but the error now is only a couple of degrees. I'll get round to swinging for a deviation card if I decide to go anywhere where it will really matter - we usually potter up and down the coast.

**groob32** · 30-10-19, 10:56

Hi Dave, I have tried playing with the compass adjusters but they don't seem to make more than 5 degrees difference one way or the other. The compass is a Plastimo Horizon 135 (pre 2000, now discontinured), I was wondering what sort compensation range yours had?
Oops, have just read another post on compass swinging, seems I was turning the wrong adjusters on N - S and E - W headings. I did wonder about that after doing the exercise.....

**Ric** · 31-10-19, 13:25

Originally Posted by groob32

I have installed a new EV1, ACU100, P70 and wheeldrive as a replacement for an old ST4000 with a old black Mk 1 wheeldrive on my Jeanneau 32.2, and as an autopilot is is a big improvement. Unfortunately the compass (on top a standard binnacle) now has up to 18 degrees deviation (down from 30 or so before I repositoned the motor at the bottom of the wheel, slightly further from the compass). If I remove the wheel with drive and motor attached the deviation goes, so it seems it can only be the motor.
Raymarine have confimed that the new motor is more powerful but have not come up with anything more helpful. Is this something anyone else has encountered?

I have exactly same boat and also changed from the Mk1 to the "new" MkII wheel pilot - and had exactly the same experience. The compass was completely unusable and could not be corrected.

My solution was drastic and expensive, but absolutely worthwhile. I chucked the ghastly squeaky graunchy and weedy wheel pilot and fitted a underdeck Raymarine linear drive. The difference is massive - apart from no more interference with compass, I can sail in total silence, the autopilot can handle anything including confused following seas in F8, and can be turned on and off at the touch of a button.

In the end I also ditched the plastimo compass, which might be a cheaper option for you. I milled a piece of flat plastic to cover the hole, then fitted over the top of that a plotter repeater in a swivelling binnacle which is far more useful than the wobbly compass. I do have a handheld movable compass that can be fixed over the instruments if really needed, but I rarely bother with it.

**groob32** · 04-11-19, 10:21

Thanks Ric, you don't do things by half do you? I am impressed!
As you can probably tell from my above posts I wasn't really looking for anything quite so extravagant, if the possible solutions mentioned above don't work I'll just have to live with it, but hats off to you anyway.

**groob32** · 14-11-19, 17:15

Now sorted using compass adjusters, deviation down to a couple of degrees each way which seems more than adequate with a correction card. Thanks for all your replies.