Autopilot Rudder Speed: Specs That Matter

What the rudder speed spec means

The rudder speed spec describes the rate at which a drive unit moves the rudder, the outboard or the sterndrive when the autopilot commands a heading change. In plain words, it is how the steering mechanism moves when the autopilot asks for a course correction. Buyers often look for a number for this in a listing, and they rarely find one.

A listing names parts instead of speeds: a linear drive, a rotary drive, a hydraulic pump, a tiller pilot or a wheel pilot. The maker's page for that part states the steering system and the boat type the part suits. That stated match is the closest thing to a rudder speed check a buyer can make from a catalogue, and it is the check this site uses. See the drive types explainer for the names.

Rudder speed is not the same as rudder reference. The rudder reference, or feedback unit, tells the autopilot where the rudder is; the drive's speed is how the rudder gets there when commanded. A listing that omits the rudder reference is not saying anything about speed.

Some maker pages describe rudder-related behavior without a speed number. Furuno's NavPilot 300 page, for example, describes Fantum Feedback for outboard installations, a feature the page says uses a time-based rudder gain process rather than rudder angle based control. The buyer reads the stated feature, not a speed figure.

Why the drive's speed matters

What matters is that the drive moves the rudder at a rate the steering system can handle. A boat with hydraulic steering needs a pump matched to the steering system's volume. A sailboat with mechanical steering needs a linear or rotary drive matched to the displacement the maker states. The maker's page gives those matches, and a listing that names the drive lets you compare them. The sailboat and powerboat guides read the same stated details.

It is tempting to want the fastest drive you can find. The maker's match is a better guide: the drive is chosen for the steering system, not for a race to the end of the turn. If a listing names a drive, read the maker's page for that drive before you decide.

Boat length and displacement are not speed figures, but a listing or a maker page may state them as the boat type a drive suits. That stated boat type is part of the same match. This site repeats only what a listing states, so a title that names a drive line is read as a name, not as a ranking.

Reading rudder speed in a listing title

A title names the model line and the drive, not a speed figure. Words like 'no drive', 'requires pump' or 'core pack' tell you the drive is not in the box. When the title names a pump type or a drive type, that is the clue to the rudder speed you can expect: a pump matched to the steering system, not a printed number.

• Drive name: a linear drive, rotary drive or hydraulic pump type.
• 'No drive', 'no pump' or 'requires pump': the drive is a separate order.
• 'Core pack': the pack leaves the drive out, so the speed is decided by the drive you add.
• Control head name: tells you what you operate, not how fast the rudder moves.

Hydraulic pumps and the speed they are matched to

For hydraulic steering, the drive is a pump that moves fluid to the steering cylinder. The maker's page for the pump type states the steering system volume it suits. On Raymarine's drive unit page, the pump types are listed by name and steering range:

Those ranges are the stated match, and a listing that names a pump type lets you compare against them. The pump's speed is not printed as a flow figure on that page. The buyer's job is to match the pump type to the steering system, and to ask the maker or a dealer when a listing is unclear. The hydraulic autopilot guide compares packs the same way.

For packs that leave the drive out, see the core pack article. For hydraulic steering, the pump type is the detail to compare, and the hydraulic pump flow article explains the names.

Questions to ask before you buy

These questions are the ones a buyer can ask without opening a manual. The answers decide whether a pack suits the boat, and they keep the choice on stated details instead of hopes.

• What steering does the boat have: hydraulic, mechanical, tiller, wheel or steer-by-wire?
• Does the listing name a drive, or does the title say 'no drive' or 'requires pump'?
• What boat type and steering system does the maker's page state for that drive?
• Is a rudder reference included in the pack, or is it a separate part?
• When a listing leaves a detail out, ask the seller before assuming.

What the catalogue cannot say about rudder speed

No page on this site measures a rudder speed figure, and no page here claims a measured performance level. Those are the maker's claims and a qualified installer's work. The only evidence here is what a listing states and what the maker's page states about the drive and the steering system it suits. The marine autopilot guide compares listings on stated details only.

An autopilot does not replace a lookout. The U.S. Coast Guard Boating Safety page is the place to start for boating safety information, and a qualified installer is the one to fit the drive. This site gives no installation instructions; the maker's manual and a qualified installer decide that work.

What to pick for your situation

Questions

What is rudder speed on an autopilot?

It is the rate at which the drive unit moves the rudder or outboard when the autopilot commands a heading change. It is a property of the drive and the steering system, not a number every listing prints.

Does every listing state a rudder speed?

No. Listings name the drive and the pack contents. The site only repeats what a maker page states, and the maker pages used here describe steering matches, not speed figures.

Is a faster rudder speed always better?

No. The drive is matched to the steering system and the boat type, and the maker's page is the source for that match. A faster drive is not automatically the right one.

Where do I find the rudder speed for a drive?

Look at the drive name on the listing, then read the maker's page for that drive. The page states the steering system it suits, which is the check a buyer can make. The drive explainer covers the names.

Does a core pack include a rudder reference?

A core pack leaves the drive out of the box. The rudder reference may also be a separate part in many systems, so read the pack contents on the listing and ask the seller when a detail is missing.

What does 'requires pump' mean on a listing?

It means the drive is not in the box: the listing expects you to provide a hydraulic pump separately, matched to the steering system. The title states it so you do not assume the part is included.