Sailing With An Autopilot


After seeing an autopilot for a kayak a few days ago, [Mike] thought he should send in his version of a water-borne autopilot. Compared to something that fits in a one-man kayak, [Mike]‘s creation is a monstrous device, able to keep a largeish sailboat on a constant heading.

To keep track of the ship’s bearing, [Mike] is using a very cool digital compass that uses LEDs to keep a steady heading. Also included is an amazingly professional and very expensive 6 axis IMU. To actually steer the ship, [Mike] is using a linear actuator attached to the tiller powered by a huge 60 Amp motor controller. The actuator only draws about 750 mA, but if [Mike] ever needs an autopilot for a container ship or super tanker, the power is right there.

For control, [Mike] ended up using an Arduino, 16-button keypad, and an LCD display. With this, he can put his autopilot into idle, calibration, and run modes, as well as changing the ship’s heading by 1, 10, and 100 degrees port or starboard.

From a day of sailing, [Mike] can safely say his autopilot works very well. It’s able to keep a constant heading going downwind, and even has enough smarts to tack upwind.

Videos below.


  1. Could this auto tack upwind? It could even have a little jibe warning before it jibes. It would be amazing if something like this could pilot you through any wind direction

  2. zee says:

    I think that today one could replace most of the electronics with a highend android phonethus saving you the cost of the superexpensive IMU

  3. fartface says:

    That is called an “autoHelm” and they have existed for decades. Typically they are ungodly expensive though, so his design is pretty much spot on with a commercial version but without the “for rich people only” price tag.

  4. Well, he didn’t reinvent the wheel. Similliar devices (e.g. are already buyable but it’s very impressive to see somebody build something like that from scratch!

  5. rogier21 says:

    Probably not IMO approved ;) But I wouldn’t sail with it when not monitored all the time, these seasalts can damage your electronics quite quickly.

  6. Mike Holden says:

    Thanks for featuring me!
    A few corrections: The autopilot is controlled by a atmel mega 163 board I had from a different project, the arduino is just for data logging.
    The led compass was in the original autopilot that I got the linear actuator from, it was broken (no oil). All heading info comes from the IMU.

    James: I tack by pressing the +/-100 button, then +/- 10 as needed to get on course again.

    Zee: you’re correct that there are much cheaper sensors that would work, I just happened to have this very nice IMU in my garage already. The tilt compensation is very good and any compass needs this.

    ff, pcf, nicolas: The raymarine (among others) tillerpilots are all great solutions, I just wanted to make my own.

  7. CorrodedFinger says:

    Just for the record, we have 4 x 7.5kW hydraulic pumps on my ship for the steering gear – and it’s only a small one. Just a little more than 60A @ 12V.

    Good project though.

  8. Snailor says:

    Pretty sure this is exactly like the illegal active Stability Augmentation System that was on Oracle’s AC yacht and which allowed them to come back to win from an 8-1 deficit.

  9. CapnMorgan says:

    Snailor, let it go. It was deemed legal. Nice project – well implemented :)

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