David435
Active Member
I bought a 1988 Princess 415 in October 2019 and when bringing the boat back from Essex to Chichester the autopilot would not hold a constant course and am only now trying to find out what the issue is. During the survey the autopilot was tested on the hard with 10 degree movement requests to port and starboard which transferred to the rudders correctly. The raymarine set up consists of the following:
Lower Helm RL80C Chartplotter, ST60 Tridata, ST6001 Autopilot.
Upper Helm RL70C Chartplotter, ST60 Tridata, ST6001 Autopilot.
These are connected to a S2G smart pilot by seatalk1 cables with red, yellow and screen to one connection and yellow and screen connected to the other connection. The S2G is also connected to the hydraulic pump and fluxgate compass.
As I had no idea how the autopilot had been installed I started with trying to recalibrate the smart pilot. This went well with the dockside calibration seeming to be OK , the compass having a 3 degree deviation in the seatrial calibration but then was unable to complete the Auto Learn. We got to step 12 with quite severe movements to port and starboard when the boat finally just turned in a circle. On pressing the auto button on the ST6001 the boat meanders all over the place and does not hold a straight course. I thought the fluxgate compass might be at fault so once I had moored up on our pontoon, I disconnected the compass from the S2G and ohms tested the connections with the following results:
Red - Green 5.7 ohms
Red - Yellow 5.8 ohms
Green - Yellow 8.9 ohms
Screen - Blue 8.6 ohms
These are all within +2 ohms of the resistance scale on the raymarine forum which suggests the compass is operating within limits. After testing and reconnecting the compass I noticed the ST6001 showed a bearing 146 degrees, the RL80C chartplotter showed a bearing 187 degrees and when switched to radar showed a bearing 137 degrees which makes no sense to me as I presume the same information is transmitted to all units via seatalk1. The compass is pre-raythean and is situated midships in the bilge underneath the lower companionway and fixed to a bulkhead with a join at some time to the original cables connecting to the S2G. I have also noticed 2 heavy duty battery cables in the bottom of the bilge, under the fluxgate cables, going to the bowthruster about 750mm from the actual compass and a webasco heater hose and hose connector which passes about 400mm from the compass. Instinct tells me if the compass was being affected by the heater hose or battery cables then the bearings recorded on the chartplotter and autopilot should still all be the same bearing anyway. Does anybody have any ideas what could be wrong with the setup and any suggestions about how to test to see if a fault has occurred in the S2G smartpilot or anywhere else.
Lower Helm RL80C Chartplotter, ST60 Tridata, ST6001 Autopilot.
Upper Helm RL70C Chartplotter, ST60 Tridata, ST6001 Autopilot.
These are connected to a S2G smart pilot by seatalk1 cables with red, yellow and screen to one connection and yellow and screen connected to the other connection. The S2G is also connected to the hydraulic pump and fluxgate compass.
As I had no idea how the autopilot had been installed I started with trying to recalibrate the smart pilot. This went well with the dockside calibration seeming to be OK , the compass having a 3 degree deviation in the seatrial calibration but then was unable to complete the Auto Learn. We got to step 12 with quite severe movements to port and starboard when the boat finally just turned in a circle. On pressing the auto button on the ST6001 the boat meanders all over the place and does not hold a straight course. I thought the fluxgate compass might be at fault so once I had moored up on our pontoon, I disconnected the compass from the S2G and ohms tested the connections with the following results:
Red - Green 5.7 ohms
Red - Yellow 5.8 ohms
Green - Yellow 8.9 ohms
Screen - Blue 8.6 ohms
These are all within +2 ohms of the resistance scale on the raymarine forum which suggests the compass is operating within limits. After testing and reconnecting the compass I noticed the ST6001 showed a bearing 146 degrees, the RL80C chartplotter showed a bearing 187 degrees and when switched to radar showed a bearing 137 degrees which makes no sense to me as I presume the same information is transmitted to all units via seatalk1. The compass is pre-raythean and is situated midships in the bilge underneath the lower companionway and fixed to a bulkhead with a join at some time to the original cables connecting to the S2G. I have also noticed 2 heavy duty battery cables in the bottom of the bilge, under the fluxgate cables, going to the bowthruster about 750mm from the actual compass and a webasco heater hose and hose connector which passes about 400mm from the compass. Instinct tells me if the compass was being affected by the heater hose or battery cables then the bearings recorded on the chartplotter and autopilot should still all be the same bearing anyway. Does anybody have any ideas what could be wrong with the setup and any suggestions about how to test to see if a fault has occurred in the S2G smartpilot or anywhere else.
