Autopilot for Trawlers: Long-Range Cruising

What a trawler asks from an autopilot

A trawler is a displacement-hull powerboat built for long passages. The crew spends hours at the helm, often at a steady speed, watching weather and navigation rather than the wheel. That is exactly what an autopilot is for: it steers to the heading you set while you attend to the voyage. For a trawler, the buying question is not which brand is newest; it is which drive matches the steering already aboard.

Most trawlers steer with hydraulic systems, and the drive that suits them is a hydraulic pump. Some newer boats with electronic helm controls use steer-by-wire packs. The first step is to know which type you have. The articles autopilot for hydraulic steering and autopilot for steer-by-wire describe how those names appear on listings. A displacement hull also behaves differently from a planing hull, which the article autopilot for displacement hulls explains in general terms.

Steering first: hydraulic systems

Raymarine's drive unit page is a useful example of how hydraulic pumps are named. It lists Type 0.5 for steering systems of 50 to 110cc, Type 1 for 80 to 230cc, Type 2 for 230 to 350cc, and Type 3 for 350 to 500cc, all for 12-volt power systems. Those figures describe the steering system's fluid volume, which is set by the helm pump and the steering ram. The autopilot pump moves fluid to the ram, and it must be matched to that volume.

The same page says the drive unit is the part that interfaces with the vessel's steering system to keep the boat on the right course, and it advises consulting an authorized dealer if you are not sure what steering system is installed. A trawler with twin engines still has one steering system, so the engine count does not decide the pump; the steering volume does. The article autopilot for single engine vs twin goes into that difference.

Complete packs versus core packs

A complete autopilot pack includes the drive, the heading sensor or course computer, and usually a control head. A core pack includes the sensor and control head but no drive. For a trawler, the question is whether a hydraulic pump is already aboard. Some trawlers carry a pump from an earlier autopilot or from a power-assisted steering system. If you plan to keep it, a core pack is the path that avoids paying for a second pump. If there is no pump, a complete pack with a pump is the straightforward choice. The article autopilot core pack vs complete pack compares the two, and the guides to best autopilot core packs and best complete autopilot packs list the options compared on stated details.

Control heads and two stations

A trawler often has a lower helm inside and a flybridge helm above. One autopilot can serve both stations, but the control head is the part you press to engage the autopilot and set a heading, and you may want one at each station. Some packs include a control head in the box; some list the head separately. The site's filter for 'control head in the box' separates those two cases.

Control head names on listings read like p70, p70s, GHC 50, AP44 or AP70. These are model names, not a ranking. The article autopilot control head options explains how the names read, and autopilot multi station setup covers the second-station question. The guide to best autopilots with control head lists complete systems by what the head offers.

Network integration: NMEA 2000

Long-range cruising means the autopilot works with the navigation system. The NMEA 2000 standard, described on the NMEA page, is a network that lets marine electronic devices share data, including commands and status, over a single channel. On a trawler, that network typically connects the chartplotter, the heading source, the autopilot and other instruments. When a route is active, the autopilot can steer the boat along the route legs, which is what route following means. Weather-routing software on a chartplotter or laptop can hand the route to the autopilot over the same network. The article autopilot NMEA 2000 connectivity explains the network in more detail.

The maker's page is the source for what a specific autopilot connects to. Raymarine's autopilot page says its Evolution systems use a 3D heading sensor as the central processor. Furuno's NavPilot 300 page says the system works with the maker's navigation display series and other navigation equipment. Those statements are about each maker's own lineup; for a specific chartplotter, ask a dealer.

Fuel, weather routing, and the watch

A steady heading avoids the small, constant rudder movements that come from hand steering. Over a long passage that can matter for fuel, because a boat that wanders covers more water than one that holds a line. This site states no fuel figures: the benefit depends on the operator, the boat and the conditions. An autopilot does not add power or speed; it simply keeps the helm steady.

Weather routing is done by software, not by the autopilot. The autopilot's role is to steer the route that the software produces, when the route reaches it through the network. If you plan to use weather-routing tools, make sure the autopilot you pick can accept routes from your chartplotter; that is a dealer question, not a listing claim.

An autopilot does not replace a lookout. The U.S. Coast Guard Boating Safety division provides education and safety resources for recreational boaters, and the operator remains responsible for keeping watch and avoiding collisions. The autopilot steers; the crew navigates.

What to pick for your situation

Questions

What size hydraulic pump does a trawler need?

The pump must match the steering system's fluid volume. Raymarine names Type 0.5 for 50 to 110cc, Type 1 for 80 to 230cc, Type 2 for 230 to 350cc, and Type 3 for 350 to 500cc steering systems, on 12-volt power. The boat's steering capacity is set by the helm and the ram; ask a dealer or consult the maker's manual.

Can an autopilot save fuel on a trawler?

An autopilot steers to a heading you set, which reduces the wandering that comes with hand steering. This site states no fuel figures; the benefit depends on the operator, the boat and the conditions.

Does a trawler need a separate autopilot for the flybridge?

No. One autopilot can serve both stations. A second control head is a common addition, and some packs include one head in the box. Ask the dealer whether a second head can be added to the system you choose.

How does the autopilot work with weather-routing software?

Weather routing is done by software on a chartplotter or laptop. The autopilot steers the route when the route reaches it. On many systems the route is sent over the NMEA 2000 network. The maker's page and a dealer are the sources for what a specific autopilot accepts.

What if the trawler has twin engines?

Twin engines still use one steering system. The drive choice follows the steering volume, not the engine count. The article on single versus twin engines is the place to read about that.

Does an autopilot replace the lookout?

No. The U.S. Coast Guard Boating Safety division stresses the operator's responsibility. An autopilot steers the heading; the crew must keep watch and navigate.