The primary purpose of an autopilot is to assist the helmsman by automatically maintaining the desired course, allowing them to focus on other essential onboard tasks.
Autopilot: Definition
A sailing yacht autopilot is a system installed alongside manual steering. Acting as a true crew member, it automatically steers the vessel to maintain a pre-set course with precision and consistency.
Autopilots are generally classified into two main categories.
Category 1 – Cockpit Autopilot
A cockpit autopilot operates directly on the helm, whether via a tiller or a wheel:
- On a tiller, a linear drive (ram) applies force directly
- On a wheel, a belt or geared drive powered by an electric motor controls steering
This type of autopilot is not designed for reliable operation in all weather conditions. It is best suited to yachts of up to approximately 6–7 tonnes displacement and around 12 metres in length, operating in moderate, typically summer conditions.
In heavy seas or strong winds, it cannot fully replace the helmsman.
Note: as it is installed in the cockpit, this system is exposed to weather conditions.
Installation is relatively straightforward and can often be carried out by the yacht owner without professional assistance. A cockpit autopilot typically includes:
- Fluxgate compass: continuously provides heading data to the control unit
- Electronic control unit: stores the desired course and calculates deviations to generate steering corrections
- Drive unit (power unit): actuates the helm to return the vessel to its programmed course
- Rudder angle sensor (feedback unit): continuously measures rudder position and transmits data to prevent oscillation or yaw
Category 2 – Inboard Autopilot
An inboard autopilot interfaces directly with the yacht’s steering system—mechanical, hydraulic, or directly on the rudder stock.
Unlike cockpit systems, inboard autopilots are capable of maintaining course even in demanding wind and sea conditions.
Their components are distributed throughout the vessel:
- The compass is installed inside the hull, near the centre of gravity
- The drive unit is typically located aft, near the steering quadrant
- The control unit is usually positioned close to the helm station
Additional Components
Inboard systems may be enhanced with:
- Gyro sensor (gyrocompass): detects rapid angular accelerations (e.g. beam seas) and provides faster corrective inputs than a standard fluxgate compass
- Heel angle sensor and attitude processor: particularly useful on high-performance sailing yachts and racing vessels
Power Unit Selection
The choice of drive unit is critical:
- On yachts under 15 metres, a linear actuator powered by an electric motor or hydraulic pump typically acts directly on the rudder stock
- On vessels with hydraulic steering, the actuator may be replaced by a pump integrated into the steering circuit
Installation is complex and professional fitting is strongly recommended.
Autopilot Systems: Selected Examples
Numerous marine equipment manufacturers offer advanced autopilot systems, continuously improving responsiveness and precision.
- Raymarine – Evolution EV-100: designed for hydraulic steering systems, this inboard autopilot delivers highly accurate course-keeping. It requires minimal calibration and provides continuous monitoring of pitch, roll, yaw and heading. Installation is flexible (above or below deck, even offset from the vessel’s longitudinal axis), and contributes to reduced fuel consumption and optimised passage times.
- Simrad Autopilot Systems: Simrad offers a comprehensive range of controllers, processors, displays and sensors, including virtual rudder feedback (VRF) technology. These systems can be integrated with chartplotters, providing enhanced navigation control and situational awareness.
- Garmin GHP Reactor™ Series: featuring a 9-axis solid-state heading system, these autopilots deliver exceptional performance even in rough sea conditions. They improve course accuracy while reducing energy consumption.
A well-selected and properly installed autopilot system is a critical asset on board, enhancing navigational precision, operational efficiency and onboard safety—particularly during extended passages or short-handed sailing.
