Autosteering

Shorthanded cruisers, just like shorthanded off-shore racers, require reliable, efficient and accurate self-steering: Round-the-clock helming is feasible only for fully-crewed yachts.

Both, windvanes and autopilots (with electro-hydraulic drives) have been successfully deployed off-shore – including round-the-world races and high-latitude passages to the most extreme areas.

	Windvane	Autopilot
Function (state-of-the-art is described, some other approaches are in use)	exploits wind- and hydrodynamics: the wind vane is turned by the wind to maintain a constant wind-anglevia a mechanical transmission, the wind vane adjusts the angle of the servo rudderdepending on this angle, water flow forces the rudder – mounted on a pendulum assembly – to starboard or portthe force of the pendulum movement is transferred to the steering system through lines and pulleys	exploits electronics, electrics and hydraulics: sensor signals – e.g., compass, GPS, rudder angle, speed, gyro – are processed in a computer/control unitthe required course corrections are calculated and sent to the power unitthe power unit amplifies the signal and powers the electric actuator pump accordinglythe pump moves hydraulic fluid to the hydraulic piston-cylinder assemblythe assembly pushes or pulls the rudder arm to the necessary position
Energy	wind and the movement through water – requires no additional energy	electricity – sufficient generation capacity necessary
Mode – Compass vs. Wind	steer to (apparent) wind, which under sail is safer and more efficientcan be combined with a small tiller pilot, to steer to compass using very little electricity	steer by default to compass or GPSsome units can also steer to wind, both true and apparent; generally, the better, the higher end the control unit and the more sensors are connected
Performance	very good – as long as they are set up correctlythe ship is trimmed properlythe winds aren’t highly variable (e.g., in fjords)	modest to impressive – depending on the money spent and quality of installationturning or jibing using the autopilot is convenient when single-handed and under engine
Complexity	low-tech – KISS	reasonably to highly complex depending on setup and options
Reliability	very reliable, with multiple reports of trouble-free round-the-world service and decades of use without breakage and minimum repairs only	became more reliable over the years but “electronics are brittle” and there are a lot of pieces that can potentially cause problems – carrying of spares advised
Cost	€€ purchase€ TCOdecades of trouble-free service are hard to beat	€ – €€€€ purchase€€ – €€€€ TCOpurchasing cost from inexpensive to very expensive; TCO high due to breakage
Integration w/ship electronics	are entirely independent of ship electronics unless a tiller pilot is added and interfaced	typically, fully integrated with ship electronics taking advantage of sensors that would be needed anyways (e.g., depth, speed, wind, barometric pressure)allowing to follow the planned track from the multifunction device

To support the owner’s choice, whatever it may be, the necessary attachment points are all welded into the hull to allow for quick and reliable installation for the

• Windpilot Pacific, which has proven itself in thousands of installations. It is mounted on the stern and acts on one steering hub.
• Octopus Hydraulic Linear Drive, reliable thanks to few moving parts and efficient due to its adjustable flow rate pump. One or two can be installed
  • acting directly on the rudder arms in the steering compartment
  • ready for connection of the control and power units of any autopilot brand

A reliable setup can be accomplished rather inexpensively with a Windpilot, some spare parts and two inexpensive tiller pilots that provide autopilot functions when under engine. The pragmatic option, which makes most sense for the most cruisers is a Windpilot combined with a mid-of-the range to high-end autopilot and a tiller pilot as a backup. At the high-end, the sky is the limit, both in terms of cost and features.

Options
Primary	Secondary	Note	Usage
Windpilot    (with tiller pilot)	spare partssecond tiller pilot	lowest-cost feasible option	sail: WP motor: WP+TP
Windpilot    (with tiller pilot)	low-end autopilot	pragmatic low-cost option	sail: WP motor: AP; WP+TP backup
mid-tier to high-end autopilot	Windpilot    (with tiller pilot)	in many ways the best of all worlds, allowing to use either to its best advantage	sail: WP or AP to wind motor: AP; WP+TP backup
Windpilot    (with Tillerpilot)	mid-tier to high-end autopilot
mid-range to high-end autopilot	low-end autopilot	all electronic option with varying level of backup – considerable to high cost.	sail: AP to wind motor: AP
high-end autopilot	mid-tier autopilot		sail: AP to wind motor: AP