Raymarine Autopilot - course keeping

[snowleopard]

For all those out there with a below-decks Raymarine autopilot, how much does it wander from the set course when motoring in flat water? I've managed to tune mine down to snaking 5° either side of the course but that still seems pretty sloppy considering I can keep it within 2° manually by touching the wheel about once a minute.

 

[AngusMcDoon]

I crewed on a boat last year with a below-deck Raymarine autopilot. When motoring in windless completely flat conditions the course keeping was pretty poor, regular slow snaking. I commented to the owner how poor it compared to my Raymarine tiller pilot, which in the same conditions would leave a dead straight wake for as far as it could be seen.

Twiddling with the control settings made no improvement. However, a bit of mechanical investigation found some slop in the rudder mounting. This was temporarily fixed with a bit of stuffing in the right places. Result - a dead straight wake.

 

[Guest]

Often course wandering can be upset by the level of damping used to maintain course. If set to slack .... the boat wanders of significantly before autohelm starts to correct. If the setting si too tight - you get overcorrection and literally see-sawing about the mid-course.

Both can lead to significant snaking .... the trick is to find the balance point that allows the boat to act / yaw etc. without upsetting the course keeping too much.

Some installations allow the auto-detection of sea-state to be turned off ... this also has a bad effect ...

All Autohelms require settling time - irrespective of changing settings or not ........... first period once switched on they are sensing boats steerage charatcteristics and building a plot to create an automatic sea-state steering mode. Switch it off and away you go on see-saw !!

Maybe some of above ?

 

[Ships_Cat]

Below decks electric linear drive, Type 300 course computer on monohull goes in a dead straight line under power in flat water, straighter than I can steer.

Prop wash on spade rudder means it has to manage a slight offset helm do do so.

John

 

[awyatybw]

Similar problem last year. 2 quadrants on rudder stock: one for autopilot linear drive, one for wheel steering. The autopilot rudder reference transducer is connected to the wheel steering quadrant, which had some slop in it (hopefully now removed). Result: poor course-keeping by autopilot.

 

[Talbot]

I have an old AH3000 and would be delighted with a 5 degree squiggle /forums/images/graemlins/laugh.gif

one setting that may be causing the problem is the speed setting - you may have this at a set speed, or it might be taking speed from GPS, but the speed in use will effect the amount of rudder being used to maintain course

 

[smurfer]

I have an S3G below deck pilot, if anything metallic is stored any where near the course computer the pilot will zig-zag something terrible.