Hydraulic Autopilots: Sizing and Compatibility

What hydraulic steering means for an autopilot

Hydraulic steering uses fluid pressure to turn the rudder or outboard. Many powerboats, and some sailboats with hydraulic systems, use this setup. An autopilot for hydraulic steering replaces the physical link between the helm and the drive with a hydraulic pump that the autopilot controls.

The pump is the part that moves the steering fluid. It is sometimes called a hydraulic pump or a reversing pump. The pump connects to the existing hydraulic lines, so the autopilot can push fluid one way or the other to steer the boat. For a complete system, you can see complete autopilot packs that include the pump.

Matching the pump to your steering system

The most important step is matching the pump to your boat's hydraulic steering system. The maker's product pages state the hydraulic fluid volume range that each pump is designed for. For example, Raymarine lists Type 0.5, Type 1, Type 2, and Type 3 hydraulic pumps, each with a stated range in cubic centimeters (cc) and cubic inches.

You need to know your steering system's fluid volume. That number is not always in the boat's manual, and it is not something you can guess from the boat's length or weight. The maker's guidance is to consult an authorized dealer if you are not sure what type of steering system is installed.

The pump's stated range is the only reliable way to compare. If a listing says "Type 1 Hydraulic Pump" and the maker's page says it is for 80-230cc, then you know the range. If your steering system falls outside that range, that pump is not the right match. For a broader comparison, see hydraulic autopilots.

Reading pump names on a listing

Autopilot listings often name the pump by a type number, such as Type 0.5, Type 1, Type 2, or Type 3. These names come from the maker's product line, not from a universal standard. The same type number from a different maker may mean a different range.

When you see a pump name on a listing, look for the maker's page that explains what that name means. For Raymarine, the drive unit page lists the hydraulic pump types and their stated cc ranges. For Furuno, the NavPilot 300 page mentions pump models like PUMPOCT16-12 and PUMPOCT10-12, but the page does not state the fluid volume ranges for those pumps.

If a listing does not state the pump's range, that is a missing detail. You can ask the seller for the maker's part number and then look up the maker's page. If the maker does not state a range, you cannot assume one. For packs that leave the pump out, see core packs.

Pump versus drive: what the words mean

In autopilot listings, "drive" is a general word for the part that moves the steering. For hydraulic steering, that drive is a hydraulic pump. Other drive types are linear drives, rotary drives, and tiller drives. The drive type must match the steering type.

A hydraulic pump is not the same as a linear or rotary drive. A linear drive pushes a rod, a rotary drive turns a shaft, and a hydraulic pump moves fluid. If your boat has hydraulic steering, you need a hydraulic pump, not a linear or rotary drive.

Some autopilot packs include the pump in the box. Others are core packs that leave the drive out, so you keep an existing drive or buy one separately. The listing will say whether the pump is included. For a detailed look at drive types, see autopilot drive types.

Power and voltage considerations

Hydraulic pumps are electric and need a power supply. The listing or the maker's page will state the voltage, such as 12-volt or 12-24 VDC. For example, Raymarine's Type 0.5 hydraulic pump is for 12-volt power systems, and Furuno's NavPilot 300 uses 12-24 VDC.

You need to know your boat's electrical system voltage. Most small boats are 12-volt, but some larger boats use 24-volt. If the pump's stated voltage does not match your boat's system, it will not work.

The power draw in amps or watts is not stated on the source pages, so this article does not give those figures. You can ask the maker or a dealer for the pump's power requirements if the listing does not state them. For more on power, see autopilot power consumption.

Compatibility with steering systems

Hydraulic steering comes in different forms. Some boats have a simple hydraulic helm, others have power-assisted hydraulic steering, and some have electronic or drive-by-wire systems. The autopilot pump must be compatible with the specific steering system.

The maker's pages name the steering types they support. Raymarine's drive unit page says the Evolution Autopilots accommodate hydraulic, mechanical, and power-assisted stern drive systems. Furuno's NavPilot 300 page mentions outboard vessels with hydraulic steering and reversing pump control, and also Dometic Optimus Electronics steering systems for some Suzuki outboards.

If your boat has a non-standard steering system, such as a Yamaha Helm Master or Volvo Penta IPS, the listing may name that system. For example, Furuno lists NavPilot 300-HM for Yamaha HelmMaster and NavPilot 300-IPS for Volvo IPS. These are special packs, not standard hydraulic pumps.

The source pages do not state that any pump is compatible with every hydraulic system. Compatibility is a specific claim that only the maker can make. If a listing says "compatible with" a system, check the maker's page to confirm. For steer-by-wire systems, see steer-by-wire autopilots.

Questions to ask before you buy

Before you choose a hydraulic autopilot, ask these questions:

What is the hydraulic fluid volume of my steering system?

What is the pump's stated fluid volume range?

Is the pump included in the pack, or is it a core pack without a drive?

What voltage does the pump need, and does my boat have that voltage?

Does the maker's page state compatibility with my steering system type?

If the listing does not state the pump's range, ask the seller for the part number and look up the maker's page.

• Check the maker's product page for the pump's stated range.
• Ask an authorized dealer if you are unsure about your steering type.
• Compare the pump's range to your steering system's fluid volume.
• Confirm the voltage and the included parts before ordering.

What the catalogue cannot say

The catalogue on this site lists the stated details from the maker's pages. It cannot tell you whether a pump will fit your specific boat, because that depends on your steering system's fluid volume and type. The catalogue also cannot give installation steps or performance claims.

The maker's manual and an authorized dealer are the sources for installation and fit. This article does not provide installation instructions, and the site does not make safety claims. An autopilot does not replace a lookout, and the U.S. Coast Guard Boating Safety page emphasizes the importance of boating safety courses and responsible operation. For more on choosing a control head, see autopilot control head options.

What to pick for your situation

Questions

What is a hydraulic autopilot?

A hydraulic autopilot uses a pump that connects to your boat's hydraulic steering lines. The pump moves fluid to turn the rudder or outboard, controlled by the autopilot system.

How do I know which hydraulic pump to choose?

You need to know your steering system's hydraulic fluid volume and match it to the pump's stated range. The maker's product page states the range, such as Raymarine's Type 1 pump for 80-230cc. If you are unsure, ask an authorized dealer.

Can I use a linear drive with hydraulic steering?

No. A linear drive pushes a rod and is for mechanical steering. Hydraulic steering requires a hydraulic pump. The drive type must match the steering type.

Does a core pack include the hydraulic pump?

No. A core pack leaves the drive out, so you keep an existing pump or buy one separately. A complete pack includes the pump. The listing will say which one it is.

What voltage do hydraulic autopilots use?

Most use 12-volt or 12-24 VDC. Check the pump's stated voltage and your boat's electrical system. For example, Raymarine's Type 0.5 pump is for 12-volt systems.