Autopilot Holding Torque: Why It Matters

Holding torque vs peak torque: what the words mean

An autopilot drive applies force to the boat's steering. Two words describe that force: peak torque and holding torque. Peak torque is the highest force a drive can produce for a short moment, used when the autopilot makes a course correction. Holding torque is the lower, sustained force a drive keeps applying to hold the rudder, wheel, or tiller at the commanded position.

Think of a correction as a push and holding as a steady support. The peak push brings the boat back to the heading; the holding support keeps it there. Both matter, but they answer different questions. A listing or drive name may give you the drive type but rarely a torque number.

Why holding torque matters for course keeping in waves

In calm water, an autopilot makes small corrections and the holding demand is modest. In waves, the water pushes the bow or stern, and the boat works away from the heading. The autopilot must correct, then hold, then correct again. A drive that can only produce a brief peak will make each correction, but it may not keep the boat on the heading between corrections.

That is why holding torque is the quality most connected to steady course keeping in waves. The drive needs to keep applying force while the wave pushes. The exact force a given boat needs is not something a listing states. The maker's page and a dealer decide fit. See torque requirement and drive types for more on how drives apply force.

What a listing can and cannot tell you about torque

A listing title names the pack or drive: Type 1 hydraulic pump, rotary drive, linear drive, wheel pilot, tiller pilot. That name tells you how the drive applies force, not how much force it produces.

This site's catalog compares stated details: steering type, boat type (sail or power), drive in the box, control head in the box, model line. Torque figures are not part of the stated details, so a missing torque number is not a gap in the listing; it is information the maker's page carries.

When a listing says "no drive" or "requires pump", the drive is left out of the box on purpose. The buyer then chooses a drive from the maker's page, and that page states which steering systems the drive suits. Read about core packs without a drive and complete packs versus custom setups.

Drive types and the holding job they do

Different drive types apply holding force in different ways. These are names a listing may carry, and each one matches a steering system:

The steering already aboard decides which drive type is right. The maker's page states the steering systems each drive suits. Raymarine's drive unit page, for example, describes the drive as the part that interfaces with the vessel's steering system and lists hydraulic, mechanical and power assisted systems. See hydraulic steering and tiller steering for the matching guides.

• Tiller pilot: attaches at the tiller for tiller-steered sailboats.
• Wheel pilot: acts on the wheel for wheel-steered sailboats.
• Hydraulic pump: moves hydraulic fluid to steer boats with hydraulic steering.
• Linear drive: pushes a pushrod for mechanical or hydraulic steering.
• Rotary drive: turns a shaft for mechanical steering.
• Steer-by-wire pack: for boats with electronic helm systems; it has no hydraulic pump or drive in the box.

Questions to ask before you buy

Because holding torque is not printed on a listing, the buyer's job is to ask the right questions. The answers come from the maker's page or a dealer.

The answers to those questions matter more than any single torque figure. The drive has to match the boat's steering before it can hold a course in waves. Compare your options in the best marine autopilot guide and the best hydraulic autopilots guide.

• What steering system does the boat have: tiller, wheel, hydraulic, or electronic helm?
• Does the maker's page state the steering systems or vessel size the drive suits?
• Is the pack a complete pack with a drive in the box, or a core pack that keeps an existing drive?
• If the listing says "no drive", which drive does the maker's page recommend for this steering type?
• Does the boat already have a control head, or does the pack need one in the box?

Holding the course is not holding the watch

An autopilot holds a heading chosen by the operator, but it does not take over the watch. The U.S. Coast Guard Boating Safety division provides boating safety resources and courses for recreational boaters. The operator stays responsible for a proper lookout and for the safe operation of the boat.

This site makes no safety claims about any autopilot. The drive's job is steering; the operator's job is watching.

What to pick for your situation

Questions

What is holding torque in an autopilot?

Holding torque is the sustained force a drive applies to keep the rudder, wheel, or tiller at the commanded position. It is the force that keeps the boat on the heading between corrections, not the brief push used to make a correction.

What is peak torque in an autopilot?

Peak torque is the highest force a drive can produce for a short moment, used to make a course correction or a turn. It is a short event, while holding torque is a continuous demand.

Why does holding torque matter in waves?

In waves, the water constantly pushes the boat off the chosen heading. The autopilot must correct, then hold, then correct again. Holding torque is the force that holds the boat between corrections, so steady course keeping depends on it more than on a brief peak burst.

Do autopilot listings state torque figures?

Usually not. A listing names the drive type and pack contents, but torque figures are not part of the stated details. The maker's page and a dealer are the sources for the drive's capabilities.

Does a larger boat need more holding torque?

A larger boat usually places a higher demand on the steering, but the answer is not a simple number. The maker's page states the steering systems and vessel sizes each drive suits. Match the drive to the boat's steering and check the maker's stated fit.

Can a tiller pilot hold a course in waves?

A tiller pilot suits tiller-steered sailboats. Whether it holds in waves depends on the boat and the maker's stated fit, not on a listing claim. Ask a dealer and read the maker's page.

Where can I find the holding torque of a drive?

The maker's page is the best source. If the page does not state a torque figure, ask a dealer. A listing on this site only states the details the seller provides, and torque is not one of them.