Autopilot Drive Speed: Specs and Trade-Offs

What drive speed means on a listing

Drive speed describes how fast the drive unit moves the boat's rudder or steering mechanism. On a listing or maker page it is usually given in degrees per second, a value that tells you how quickly steering responds to a course correction command.

The drive unit is the part that interfaces with the vessel's steering system to keep the boat on course, as Raymarine's drive units page explains. Whether the drive is a tiller drive, a wheel drive, a hydraulic pump, a rotary drive or a linear drive, the speed at which it moves the steering is part of what the autopilot uses to hold a heading. See how drive types differ for a fuller picture.

A drive speed value is one stated detail among several. The drive type, the steering system it suits and the boat type the maker intends are just as important, and the site's marine autopilot comparison weighs all of them together.

Why rudder response matters

Faster rudder response lets the autopilot counter a deviation quickly. On a planing powerboat moving fast, the boat can wander quickly, so a drive that moves the rudder promptly helps hold the line you set. The guide to powerboat autopilots covers this kind of boat.

Slower rudder movement is not a flaw. On a displacement sailboat or a trawler, a gradual rudder movement produces gentler corrections, which matters when the boat is heavy and answers the helm slowly. The sailboat autopilot guide explains how a sail drive is matched to the boat.

The trade-off is that a drive that is too fast for the boat can cause overshoot and a jerky feel, while a drive that is too slow can lag when a wave pushes the bow. The maker's guidance matches drive units to boat type and steering system, which is why the same autopilot line appears in several drive versions.

How boat type shapes the choice

The boat's hull and steering decide how fast the rudder needs to move. A center console with hydraulic steering and outboards behaves differently from a tiller-steered sailboat, and the autopilot pack names tell you which boat type the maker intends.

Raymarine's pack page lists the EV-100 Tiller Autopilot as a tiller drive autopilot for small sailboats and the EV-100 Power Pilot as an autopilot for small powerboats with hydraulic steering. Furuno's NavPilot line includes packs for outboard, inboard and electronically steered vessels. The drive version in the pack is chosen to match the steering system, not just the boat length.

If you are unsure which steering system is aboard, the maker's advice is to consult an authorized dealer or contact the maker directly, as Raymarine's drive units page suggests.

Reading the maker's page and the listing

Not every listing states drive speed in degrees per second. Some give only the drive unit type, the steering system it suits and the boat type the maker recommends. Those stated details are exactly what this site compares in its complete pack guide and its core pack guide.

When a listing omits a number, the maker's page is the place to look. The same drive unit can appear in several packs, and the pack name usually tells you the drive type and the intended boat type.

Trade-offs, not rankings

Drive speed is a trade-off, not a score. A faster drive suits a quick, light boat; a slower drive suits a heavy, steady boat. What matters is that the drive matches the steering system and the way the boat responds to the rudder.

The maker's drive unit pages are the source for matching. Raymarine's drive unit selection lists cockpit tiller drives, hydraulic pumps, rotary drives and linear drives, each for a different steering system. The control head and the drive work together through the boat's network, and the manufacturer's manual is the guide for installation and setup.

For more on the related specs, see hydraulic versus linear drives and rudder speed specs.

Questions to ask before you choose

These questions lead you to the stated details. The answers on the listing and the maker's page are the evidence this site uses in its comparisons, and the control head guide shows how the head completes the system.

• What steering system does the boat have: tiller, wheel, hydraulic, cable or steer-by-wire?
• Does the listing name the drive unit type, such as linear drive, rotary drive or hydraulic pump?
• Does the maker's page match the drive to a boat type or steering system?
• Is the drive included in the pack, or is the pack a core pack without a drive?
• Which control head is in the box, and does the pack include a rudder reference where one is required?

What to pick for your situation

Questions

What does drive speed, in degrees per second, mean?

It is how fast the drive unit moves the rudder or steering mechanism. A higher number means quicker rudder movement; a lower number means more gradual movement. The right value depends on the boat type and steering system.

Is a faster drive always better?

No. A drive that is too fast for the boat can cause overshoot and a jerky feel, while a drive that is too slow can lag when the boat needs a quick correction. The maker's guidance matches drive speed to the boat type.

Where do I find the drive speed for an autopilot pack?

Look at the listing's stated details and the maker's page. Some listings name the drive unit type; the maker's page gives the steering system and boat type the drive is intended for.

Does drive speed depend on the steering type?

Yes. Hydraulic steering, cable steering, tiller steering and steer-by-wire all move the rudder differently. The drive unit must match the steering system that is already aboard.

Can I compare drive speed across brands?

Compare the stated details only. This site compares listings on stated details and points you to the maker's page for the exact drive description.

What if the listing does not state drive speed?

Check the maker's page and the pack name. A pack name often tells you the drive type and intended boat type, such as a tiller autopilot for small sailboats or a power pilot for small powerboats with hydraulic steering.