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.

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-angle • via a mechanical transmission, the wind vane adjusts the angle of the servo rudder • depending on this angle, water flow forces the rudder – mounted on a pendulum assembly – to starboard or port • the 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 unit • the required course corrections are calculated and sent to the power unit • the power unit amplifies the signal and powers the electric actuator pump accordingly • the pump moves hydraulic fluid to the hydraulic piston-cylinder assembly • the 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;• steers to (apparent) wind, which under sail is safer and more efficient • can be combined with a small tiller pilot, to steer to compass using very little electricity;• steers by default to compass or GPS • some units can also steer to wind, both true and apparent - generally, the better, the higher end the control unit is and the more sensors are connected Performance;very good – as long as • they are set up correctly • the ship is trimmed properly • the winds aren’t highly variable (e.g., in fjords);modest to impressive – depending on the money spent and quality of installation. Turning 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 only requiring minimum repairs;has become 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 € TCO - decades of trouble-free service are hard to beat;€ – €€€€ purchase €€ – €€€€ TCO - 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 • takes 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.

The windvane option is the Windpilot Pacific, which has proven itself in thousands of installations. It is mounted on the stern and acts on one steering hub.

For Autopilot support, one or two Octopus Hydraulic Linear Drives, may be installed. These are reliable thanks to few moving parts and efficient due to its adjustable flow rate pump. The drives

act directly on the rudder arms in the steering compartment
are 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

Windpilot Pacific
Octopus Drive

Electro-Hydraulic Drive