SYSTEM ELEMENTS

Pilot computer The core of the system that takes inputs from the various sensors, calculates changes in rudder angle required and activates the drive unit to achieve these.

Drive unit The equipment that moves the rudder. This will vary depending on the type of boat and simply takes a 12V or 24V feed from the pilot computer.

Pilot controller The user interface, which usually includes an LCD display and sometimes a remote control.

Sensors These include rudder angle, wind speed and angle, plus a compass. Boat speed is also needed for true wind angle calculations. A gyro compass that senses the rate of turn, as well as the instantaneous heading, was often used but newer models have a solid-state 9-axis sensor that also measures heel, roll and pitch. These give more accurate data for radar overlays on chart plotters, including MARPA (Mini Automated Radar Plotting Aid) tracking of other vessels.

For optimal performance the quality of wind data is important. Given the sensor is at the masthead it moves around a great deal in big seas causing peaks and troughs in the readings. Traditionally this has been dealt with by damping the signal – taking an average reading over a longer time period – but that’s not a good option if you want a quick pilot response. NKE gets around this with its High Resolution products that measure the boat’s motion, calculate the movement of the masthead and then uses this data to smooth the wind angle measurements in a process that takes only milliseconds. NKE says the extent to which this reduces rudder movement translates to a reduction in power consumption of up to 40%.