modify an autohelm to add a wireless remote control

When I purchased Serenade, she came equipped with a Navico autohelm system. It connects to the tiller and the internal microcontroller drives an actuator arm that adjusts the tiller to maintain a particular course. You engage the automatic mode of this unit when you reach the desired heading, and the internal fluxgate compass provides a steady reference for the course direction. The actuator arm will move the tiller back and forth to maintain a steady course, counteracting any wind or current forces that might push you in the wrong direction.

There are port and starboard steering buttons that accept course change commands. Pressing one of them with a momentary push will change the course by one degree.  Pressing it quickly 3 times will change the course by 3 degrees, and she will come around and lock onto the new heading. Hold the button down for a few seconds, and she'll alter course by ten degrees. There are other combinations that allow you to tack or reverse course, but I mainly using the minor course changes only.

The picture on the right shows the inside of the unit, with the cover removed. The three buttons on the printed circuit board at the bottom, just above the ribbon cable, are the actual control switches used to select course changes and mode of operation.

The autohelm system quickly became indispensable, especially when I am single-handing her. Whether I'm going below to warm up in front of the fireplace or up on the bow for a sail change, I can count on it to maintain my course heading while I am otherwise occupied. It doesn't compensate for tide drift and other influences, but occasional minor adjustments will keep your heading true. It is truly one of the most useful devices I have ever seen in the boating world.

There were two things I didn't like about the autohelm: having to run back to the cockpit to adjust my course, and having it and the tiller taking up a large part of the cockpit. You can read about how I resolved these problems by following the links below.