Boat Steering and Autopilot: Steering Options and Automatic Steering

A boat's steering system is one of the most important factors in handling and ease of use. The choice between mechanical cable steering and hydraulic steering directly affects the driving experience, maintenance needs, and the ability to add an autopilot later. An autopilot, meanwhile, is an electronic device that automatically keeps the boat on a set course without continuous manual steering, freeing the boater for other tasks on long passages.

What steering options are there for a boat?

A boat's steering system transmits the movement of the wheel or tiller to the outboard motor or rudder. There are two main types to choose from: mechanical cable steering and hydraulic steering. Each has its own advantages and suitability for different boat size classes.

Mechanical cable steering

Mechanical cable steering is a simple, cost-effective solution where the wheel's movement is transmitted directly via a steering cable to the outboard motor or rudder. When the wheel is turned, a rigid but flexible metal cable pushes or pulls the motor in the desired direction.

Key characteristics of cable steering:

Advantages: The simple construction is reliable and less prone to faults. Installation costs are low compared with hydraulic steering. Cable steering gives a direct, tactile feel connected to the motor or rudder. Modern steering cables are designed to reduce friction, making steering light on smaller boats.

Disadvantages: Steering can become heavy at high speeds or with more powerful motors. The cable wears over time and needs regular maintenance, such as lubrication. In freezing weather, the cable can stiffen, making steering difficult. A broken cable results in a complete loss of steering ability.

Suitability: Cable steering is excellently suited to small and medium-sized motorboats with an engine under 115 horsepower. It's also an economical choice for boats where the run from the wheel to the motor is relatively short.

Hydraulic steering

Hydraulic steering uses hydraulic pressure to transmit the wheel's movement to the rudder or outboard motor. The system consists of a helm pump (behind the wheel), a hydraulic cylinder, and hydraulic hoses through which the hydraulic fluid moves. When the wheel is turned, the pump creates pressure that drives the hydraulic fluid through the hoses to the cylinder, which turns the outboard motor or rudder.

Key characteristics of hydraulic steering:

Advantages: Steering is light and consistent at all speeds and in all conditions. Hydraulic fluid doesn't compress, eliminating lag and play in the steering. The system withstands wear well and doesn't require constant maintenance. An autopilot integrates seamlessly with hydraulic steering. Modern systems may include power-assist steering, which further eases heavy turns.

Disadvantages: The purchase price is higher than cable steering. A hydraulic fluid leak can lead to steering failure, though this is rare in well-maintained systems. Repairing the system on a trip is more challenging than with mechanical steering.

Suitability: Hydraulic steering is the best choice for medium and large boats and vessels with powerful engines. It's excellently suited to boats where engine power exceeds 100 horsepower or where an autopilot purchase is planned for the future.

Comparison: Mechanical vs. hydraulic steering

What is an autopilot and why do you need one?

An autopilot is an electronic navigation device that automatically steers the boat to a set course without continuous manual steering. The system uses sensors, such as a compass, gyroscope, and GPS, to keep the heading steady even in waves, wind, or currents. Modern autopilots can adapt to sea conditions and steer predictively, which saves fuel and reduces the boat's motion.

Key functions of an autopilot:

Course holding: The autopilot keeps the boat on the set compass heading, continuously correcting for deviations caused by waves, wind, and current. This frees the boater from manual steering and significantly reduces physical and mental strain on long passages.

Route navigation: Compatibility with a chartplotter enables automatic navigation between waypoints. The autopilot automatically turns the boat toward the next waypoint and signals as the destination approaches.

Special functions: Modern autopilots offer special features such as trolling patterns (S-turns, circle running), wind steering for sailboats, and a MOB (Man Overboard) function for emergencies. Systems learn the boat's behavior and optimize steering commands over time.

When is it worth getting an autopilot?

An autopilot is especially useful in the following situations:

Long passages: On outings lasting over an hour, an autopilot significantly reduces fatigue. The boater can focus on navigation, cooking, or simply enjoying the trip without continuous steering.

Solo boaters: An autopilot is nearly essential equipment for solo sailing, since it allows the boat to be steered while the skipper handles other tasks such as sail trim, anchoring, or navigation.

Trolling: For anglers, an autopilot is an invaluable aid when you want to hold a specific speed and run steady trolling patterns without constantly focusing on the helm.

Rough conditions: In challenging sea conditions, an autopilot holds a course more precisely than manual steering, reducing the boat's roll and improving comfort. Modern systems with gyroscopic sensors react to waves predictively.

Autopilot types: tiller pilot, wheel pilot, and hydraulic pilot

Autopilots fall into three main types based on the boat's steering system. The right choice depends on boat size, steering type, and intended use.

Tiller pilot

A tiller pilot is mounted directly on a small boat's tiller. The unit is compact and easy to install, making it a popular choice for small sailboats and rowboats steered by tiller.

Suitability: Sailboats under 30 feet with tiller steering. An affordable option for basic navigation on inland and coastal waters.

Price range: €400–900

Wheel pilot

A wheel pilot is mounted directly on the steering wheel with a mechanical drive unit. An electric motor turns the wheel according to commands calculated by the autopilot's control software. The system suits medium-sized boats with cable steering or light hydraulic steering.

Suitability: 25–40 foot motorboats and sailboats with a steering wheel. Works with both cable and hydraulic steering.

Price range: €800–2,000

Hydraulic pilot

A hydraulic pilot connects directly to the boat's hydraulic steering system via a separate hydraulic pump. The autopilot drives the pump, which moves the steering cylinder the same way the wheel's pump does. This is the most powerful and precise type of autopilot, suited to larger boats and demanding conditions.

Suitability: Motorboats and sailboats over 35 feet with hydraulic steering. The best choice for offshore cruising and long-distance sailing.

Price range: €1,500–4,500 (pump and control unit)

Autopilot technologies: fluxgate, gyro, and AHRS

An autopilot's accuracy and performance depend heavily on its sensor technology. Development has progressed from traditional magnetic compasses to smart, multi-function sensors.

Fluxgate compass: A traditional electronic compass that measures the direction of the earth's magnetic field. A fluxgate compass is reliable, but suffers from lag and errors caused by waves and acceleration. The compass measures heading about once a second, which can lead to slow corrections in changing conditions.

Gyroscope (rate gyro): An angular-rate sensor measures how fast the boat's heading is changing. A gyro isn't affected by metal objects and reacts instantly to the boat's motion, enabling fast, accurate steering. A gyro measures turn rate tens of times per second, making it far faster than a fluxgate compass alone. The combination of a gyro and a fluxgate compass gives the best result: the gyro reacts quickly, while the fluxgate provides an absolute heading reference.

9-axis AHRS (Attitude Heading Reference System): The top tier of modern autopilots uses an AHRS system, which combines three gyroscopes, three accelerometers, and three magnetic sensors (fluxgate). The system measures the boat's roll, pitch, and yaw in all three dimensions. AHRS sensors use algorithms that fuse data from all nine sensors to produce extremely accurate, interference-free heading data. For example, Raymarine's Evolution series autopilots use the EV-1 AHRS sensor core, technology borrowed from the aviation industry.

Modern systems like Raymarine Evolution learn the boat's behavior and automatically adapt to waves, wind, and currents. This can lead to fuel savings of up to 10–15%, since the autopilot makes smaller, more precise correction movements than a human can.

Autopilot selection criteria by boat size

Autopilot choice primarily depends on the boat's size, weight, and steering system. Too small an autopilot can't control a large boat in rough seas, while too large and powerful an autopilot on a small boat is an unnecessary expense.

The boat's weight also affects the choice: a heavy displacement boat needs a more powerful autopilot than an equally sized light boat. In addition, a sailboat typically needs more steering force than a motorboat, since wind creates more resistance on the rudder.

Autopilot installation and compatibility

Installing an autopilot requires careful planning and choosing the right components. Successful installation depends on the steering system, the electrical system, and integration with other devices.

Installation on cable steering

On cable steering, an autopilot is installed by replacing the original steering cable or steering drum with an autopilot-compatible model. For example, the Lowrance Autosteer system uses a Helm-1 drive unit, which replaces the original cable-steering drum and is compatible with Morse 290, Teleflex SSC52, and similar cable steering systems.

Installation steps:

1. Remove the original steering drum

2. Install the autopilot-compatible steering drum or drive unit

3. Attach the steering cable to the drive unit

4. Connect the electrical wiring and NMEA 2000 bus

5. Install the heading sensor (fluxgate or AHRS) in a suitable location, away from metal objects and sources of magnetic interference

Installation on hydraulic steering

A hydraulic pilot connects to the boat's hydraulic steering system via a separate reversible pump. The pump is connected to the hydraulic system with T-fittings between the helm pump and the steering cylinder. The autopilot's control unit (ACU) drives the hydraulic pump electrically.

The choice of hydraulic pump depends on the steering cylinder's volume. For example, the Raymarine EV-100 suits 50–110 cm³ cylinders with a 0.5 l/min pump, while the EV-150 requires a 0.5–1.0 l/min pump for 80–230 cm³ cylinders.

Installation steps:

1. Install the hydraulic pump in a suitable location near the steering cylinder

2. Connect the pump to the hydraulic system with T-fittings

3. Fill the system with hydraulic oil and bleed it carefully

4. Install the control unit (ACU) in a suitable location

5. Connect the electrical wiring and NMEA 2000 bus

6. Install the AHRS sensor or heading sensor

7. Calibrate the system per the manufacturer's instructions (sea trial run)

Integration with navigation devices

Modern autopilots integrate seamlessly with chartplotters, radars, and other navigation devices via the NMEA 2000 bus. This enables automatic route navigation, where the autopilot follows a route planned on the chartplotter and automatically turns toward the next waypoint.

For example, Raymarine's autopilots work seamlessly with Raymarine's chartplotters, radars, and multifunction displays via the SeaTalkng network. Similarly, Garmin devices communicate over the NMEA 2000 bus, and Lowrance systems support the Micro-C network.

Autopilot use and maintenance

An autopilot's longevity and reliable operation require correct use and regular maintenance. Modern systems are largely maintenance-free, but a few important tasks ensure optimal performance.

Calibration and sea trial

Calibrating the autopilot is a critical step after installation. A sea trial is the process in which the autopilot learns the boat's behavior at different speeds and turns. During calibration, the boat is driven straight ahead at a constant speed, and the autopilot records the boat's response to steering movements.

Calibration should be redone if:

- The boat's load changes significantly (e.g., full vs. empty fuel tank)

- The autopilot starts steering inaccurately

- Changes are made to the system (e.g., propeller replacement)

Regular maintenance

Electrical connections: Check connections for corrosion at least once a season. Salt water can cause oxidation, which degrades signal quality. Clean connectors as needed and use contact spray for protection.

Hydraulic system: On hydraulic pilots, check the hydraulic oil level and quality annually. Top up oil as needed and bleed the system if the steering feels soft or uneven. Check hydraulic hoses for leaks and wear.

Software updates: Manufacturers regularly release software updates that improve autopilot performance and fix any bugs. Updates are usually installed via a USB stick or a wireless connection.

Sensor location: Make sure the AHRS sensor or fluxgate compass stays away from metal objects and sources of magnetic interference. Installing new equipment on the boat can cause interference, in which case calibration should be redone.

Get the right steering system and autopilot from Marinekauppa

Choosing the right steering system and autopilot significantly improves your boating experience. Mechanical cable steering suits small and medium-sized boats as an economical, reliable solution, while hydraulic steering offers light, precise control for larger boats and more powerful engines. An autopilot frees the boater from manual steering on long passages, improving safety and comfort, especially when solo sailing or trolling.

In Marinekauppa's extensive range you'll find quality cable steering equipment, hydraulic steering kits, and autopilots for every boat size class. Also check out our remote-control equipment to complete your steering setup.

Need help choosing the right system? Our knowledgeable staff will help you find the right solution for your boat. Order from our webshop or come visit our store!

Sources and further reading

Manufacturers and technical data:

Raymarine – Evolution Autopilot Systems: www.raymarine.com

Garmin Marine – Reactor Autopilot Series: www.garmin.com/marine

Simrad Yachting – Autopilot Solutions: www.simrad-yachting.com

Technical standards:

NMEA 2000 – Marine Electronics Standard: www.nmea.org

ISO 8848 / EN 28848 series – Safety standards for small craft remote steering systems

Industry articles:

Venemestari magazine: "A hydraulic autopilot for a motorboat": venemestari.fi

Inertial Labs: "AHRS Technology Documentation": inertiallabs.com

Disclaimer

This guide provides general guidance only and does not replace the product manufacturer's operating, installation, or service instructions. Marinekauppa is not responsible for actions taken based on this guide or their consequences. Always check product-specific instructions and consult a qualified professional if needed.