A Raymarine ST1000 detachable <a href="https://en.wikipedia.org/wiki/autopilot" class="extiw" title="en:autopilot">autopilot</a> on a small <a href="https://en.wikipedia.org/wiki/sailboat" class="extiw" title="en:sailboat">sailboat</a>.  One end of the device has a peg that fits a hole in the seat, while the other end has a movable bar that attaches to the <a href="https://en.wikipedia.org/wiki/tiller" class="extiw" title="en:tiller">tiller</a>.  By extending or retracting the bar, the device can steer the boat to maintain a set <a href="https://en.wikipedia.org/wiki/compass" class="extiw" title="en:compass">compass</a> heading.  A <a href="https://en.wikipedia.org/wiki/Global_Positioning_System" class="extiw" title="en:Global Positioning System">GPS</a> attachment is optional.
No machine-readable author provided. <a href="//commons.wikimedia.org/wiki/User:Ilmari_Karonen" title="User:Ilmari Karonen">Ilmari Karonen</a> assumed (based on copyright claims).
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