The autopilot does not hold course. What do you do now?


You are sailing smoothly into port and your automatic rudder begins to freak out and not hold course. What could have happened? There are two cases: it may be a problem that needs to be solved at the source by calling in a technician, or the pilot is having difficulty keeping the orders you have given him. This may be a good opportunity for an inspection of your on-board instrumentation.

The self-compensation of the compass
Is the compass properly calibrated? The Flux Gate electronic compasses to which the automatic pilots are connected must undergo a self-compensation procedure consisting of circling around themselves with the whole boat. During the lap an internal microprocessor records the magnetic field strength on the different prores and at the end of the lap calculates the average value, which is stored and used to automatically correct all subsequent measurements. If this operation was done poorly, or carried out under difficult conditions, it must be repeated from scratch. Also be careful not to bring metal objects or electric fields near the compass. If you have realized that the problem is self-compensation of the compass, you can navigate with the pilot in Waypoint mode (if provided) by connecting it with the GPS. Make sure the autopilot and rudder are properly connected.

Screenshot 2016-04-20 at 10:46:42 a.m.The set-up must be balanced
Of paramount importance for proper autopilot operation is that the boat is balanced, that is, the sail plan is proportionate to conditions and well adjusted. Engage the autopilot only when the sails are trim and the boat is already stable on its course. In “auto” functionality, most of the automatic pilots out there perform well in undemanding sea and wind conditions.

But if conditions become compromising, there are certain functions that need to be addressed:
Gain: is the response speed of the pilot. If you set it with a low value, the blade movements will be smooth; if you look at the compass and notice that your course wobbles too much, you need to raise the gain value, to increase the speed of response. Beware of excesses: too much gain will lead to too much “brutal” helming, resulting in a zigzag course.
The counter-stimulus. When changing direction, too high a level of counter-stimulus will produce a slow and progressive rider response. Too low a value, on the other hand, will result in too abrupt a reaction, with the rudder returning to center too soon, without the desired change in direction being completed.
Rudder coefficient: consists of reducing the amplitude of rudder movements when the speed increases. You need to know how to adjust it to have a more “ready” response. Too much information is detrimental: with big seas, one should not give too much input to the pilot.

“Wind-apparent” mode
If in most conditions the compass and waypoint modes work best, when sailing upwind the “apparent wind” mode is much more effective because it causes the pilot to react to any wind shifts, whereas it is not suitable for upwinds where the apparent wind changes with each acceleration of the boat.



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