Marine Autopilot Buying Guide: Hydraulic, Wheel and Tiller Pilots
Quick answer: Choose your autopilot by your steering system first. Boats with hydraulic steering need a reversing hydraulic pump sized to the steering cylinder. Sailboats with a wheel can use a wheel drive, and tiller-steered sailboats can use a tiller pilot. Then size the drive to your boat's displacement (loaded weight), add a modern gyro-stabilized heading sensor, and pick a control head that talks to your chartplotter so the pilot can follow routes.
An autopilot is the extra crew member that never gets tired. It holds a heading on a long run offshore, follows a route between waypoints, and frees you to rig baits, trim sails or simply watch for traffic. A properly sized autopilot steers smoothly and saves fuel. An undersized one wanders, overheats and fails when you need it most, usually in following seas. This guide covers the parts of an autopilot, how to match it to your steering, and what to look for.
Step 1: Know the parts
- Control head: the display and buttons at the helm where you engage the pilot and change course.
- Course computer: the brain that decides how much rudder to apply.
- Heading sensor: an electronic compass, ideally gyro-stabilized, that tells the computer which way the boat is pointing.
- Drive unit: the muscle that actually moves the steering: a hydraulic pump, a wheel drive, a tiller ram, or a mechanical linear drive.
- Rudder reference (optional on many modern systems): a sensor that reports rudder angle.
Many modern systems combine the computer and sensor, and some sell as complete packs so you only add the right drive.
Step 2: Match the drive to your steering
| Steering system | Autopilot drive | Typical boats |
|---|---|---|
| Hydraulic | Reversing hydraulic pump plumbed into the steering lines | Most outboard and inboard powerboats over about 22 feet, many larger sailboats |
| Mechanical cable | Mechanical drive or a conversion to hydraulic | Smaller powerboats and older boats |
| Sailboat wheel | Wheel drive that clamps to the wheel | Cruising sailboats with wheel steering |
| Sailboat tiller | Tiller pilot (push-pull ram) | Smaller sailboats with tiller steering |
| Larger sailboats | Below-deck linear or rotary drive on the rudder quadrant | Offshore cruisers and heavier boats |
Step 3: Size it correctly
Every drive is rated for a maximum displacement. Use your boat's loaded weight with fuel, water, gear and people, not the brochure dry weight. For hydraulic pumps, also match the pump to the volume of your steering cylinder, measured in cubic inches and printed on the cylinder or in your steering manual. When you are between sizes, go up. A drive working near its limit will struggle in following seas and wear out faster.
Step 4: Features that matter
- Gyro-stabilized heading: steers far more accurately in waves, especially downwind.
- Chartplotter integration: lets the pilot follow a route and fishing patterns from your plotter.
- Remote or wireless control: adjust course from the cockpit, tower or bow.
- Wind and sail modes: for sailboats, steering to apparent or true wind angle.
- Response settings: tune how tightly it holds course versus how much battery it uses.
Step 5: Installation basics
- Mount the heading sensor low and near the boat's center, well away from magnetic interference like speakers, engines and large steel objects.
- Plumb hydraulic pumps exactly as the steering and pilot manuals show, then bleed the system thoroughly.
- Run heavy enough power wire for the drive's current, with a breaker sized to the wire. See our wire and terminal guide.
- Network it to your plotter, commonly over NMEA 2000 or the brand's own network.
- Run the calibration and sea trial procedure before relying on it offshore.
Step 6: Use it safely
An autopilot steers. It does not watch. Keep a lookout at all times, know how to disengage the pilot instantly, and be cautious near other boats, in crowded channels and in heavy following seas.
Plan for the pilot's power draw too. On long runs a hydraulic drive can pull a steady current, so make sure your batteries and charging can keep up.
Our picks by boat
All in stock at Boat Supplies Direct.
Small tiller-steered sailboats
Raymarine ST1000 Plus Tiller Pilot for lighter boats, or the stronger Raymarine ST2000 Plus. Self-contained and simple to install.
Sailboats with wheel steering
Raymarine EV-100 Wheel Evolution Autopilot, a complete pack with gyro heading sensor, controller and wheel drive. For larger tiller boats, the EV-100 Tiller Evolution pack.
Powerboats with hydraulic steering
Raymarine EV-100 Power Evolution Autopilot paired with a correctly sized reversing pump, such as the Octopus Type 1 pump (up to 15 cubic inch cylinders) or the Octopus Type 2 (up to 18 cubic inch). Bigger cylinders: Octopus Type 3 (up to 30 cubic inch).
Control heads
Raymarine p70Rs Autopilot Controller with rotary knob, or the push-button p70s, for a second station or upgrade.
Frequently Asked Questions
What size autopilot do I need?
Size the drive to your boat's fully loaded displacement and, for hydraulic steering, to your steering cylinder volume in cubic inches. When in doubt, choose the next size up.
Can I add an autopilot to a boat with cable steering?
Yes, with a mechanical drive designed for cable steering, though many owners convert to hydraulic steering, which also makes the boat easier to steer by hand.
What is a tiller pilot?
A self-contained push-pull ram that attaches between the cockpit and the tiller of a smaller sailboat, steering by moving the tiller.
Will an autopilot follow my chartplotter route?
Yes, when connected to a compatible chartplotter, usually over NMEA 2000 or the brand's network, the pilot can steer to waypoints and along routes.
Where should the autopilot heading sensor go?
Low and near the boat's center of motion, away from magnetic interference such as speakers, engines, wiring and steel.
Is it safe to leave the helm on autopilot?
No. An autopilot holds a course, but it does not see other boats or obstacles. Always keep a lookout.
This guide is general information. Autopilot sizing depends on your exact boat and steering system. Confirm compatibility with the manufacturer and have hydraulic installations done by a qualified technician.
