Читать книгу SELF-STEERING UNDER SAIL - Peter Foerthmann - Страница 15

Almost all autopilots can be linked to a windvane transducer. This enables them to take the apparent wind angle signal as steering impulse. The signal comes either from the masthead unit or from a small windvane at the stern. Neither alternative produces particularly satisfactory results in any kind of swell, since the movements of the masthead unit caused by the motion of the boat or the confused readings of the stern-mounted unit caused by disturbed air have to be damped and processed considerably to obtain a useful signal. The small size of autopilot windvanes often contributes to such problems.

The volume of data required to produce precise and practicable course commands for the steering module when using the course computer to calculate the apparent wind angle is substantial: rolling, pitching, speed, acceleration, wind angle and possibly also true parameters (true wind angle etc.) must all be processed. The importance of sailing to the apparent wind angle cannot be understated; ignore it and the boat loses all its drive.