Autopilot installation & sensor issues

[Captain Jan]

I am changing my old wheelpilot for a new Raymarine linear drive  with controller etc. My existing unit has the sensor under the aft end port bunk aft quarter cabin on the  face of the plywood stringer holding in the water tank.  This is a twin quarter cabin Bav 38.

My contractor insists that due to the instrument cabling running up the center of the hull to the wheel and instrument panel, it is not practical to put the new sensor in this place as though shielded by 20mm plywood and a space of perhaps 2 to 3  ft from the  sensor to cabling, it may affect performance. He wants to mount the sensor in one of the  seat lockers that are around the table.   

I would guess where my sensor is fitted is standard Bavaria fitout. The power running through instrument cabling is negligible.  I feel that is is fine where it is but may be wrong, hence the discussion.  Has anyone had to move the autopilot sensor into the main cabin?  Any discussion on this would help, we need to start installation soon.

[geoff]

I take it that it is the heading sensor that you speak of. If so I dont think that proximity to low power cables will make any real difference. After the unit is installed the system is calibrated to the boat environment. I moved mine from under the saloon table to the front face of the rear cabin bed. It has made no difference . Geoff

[Jeffatoms]

Fluxgate compass?  It seems that Bavaia and/or the dealers have put it in many places, genetally low, on the same boat model.  I'd be concerned about nearby, big ferrous objects (i.e. engine), as such stuff may impact its accuracy.

[symphony2]

The Raymarine instructions say it should be placed as near the centre of the boat as possible and not near large lumps of metal like the engine. it is unaffected by things like thickness of plywood or proximity to the control head. My first Bavaria had the sensor in the lazarette. When I installed a new unit I put it in the cupboard in the starboard aft cabin which is common. Underneath the chart table is also common. My second boat had a factory installed Garmin and again it was in the cupboard. The sensible layout is to have the course computer on the lateral bulkhead in the starboard aft cabin under where the pedestal is and the sensor in the cupboard in that cabin. This minimises cable runs and means both are easily accessible.

[Captain Jan]

Thanks for the quick response, it's a great help, time is short as we start tomorrow.  It seems the cupboard in the quarter cabin is popular so will research this.