Single vs Twin Autopilot Drives: Pros and Cons

What are single and twin autopilot drives?

An autopilot drive is the part that physically moves your boat's steering. On a boat with hydraulic steering, the drive is a hydraulic pump that pushes fluid to the steering cylinder. On a boat with mechanical steering, the drive might be a linear or rotary unit that moves a tiller or wheel. The drive is selected to match the steering system and the boat's size. The maker's specifications, such as those on Raymarine's drive unit page, list drives for hydraulic, mechanical, and power-assisted steering systems.

A single-drive setup uses one drive unit to control the steering. A twin-drive setup uses two drive units, often smaller ones, that work together. Twin drives are sometimes used on boats with two steering stations, or when a single large drive won't fit in the available space. The choice affects installation, cost, and how the system behaves. For example, Raymarine offers a range of drive units, including hydraulic pumps, rotary drives, and linear drives, each designed for specific steering types and boat sizes. When you look at a listing, you will see the drive named as part of the pack, such as a Type 1 hydraulic pump or a linear drive. Understanding these names helps you compare what is in the box.

Why would you use two drives?

Two smaller drives can be easier to fit in tight engine rooms or behind panels. They can also provide redundancy: if one drive fails, the other may still steer the boat, though this depends on the system design. Some boats with twin engines or twin rudders may benefit from a drive on each side to balance the load. However, two drives add complexity. They require more wiring, more mounting points, and a control system that can manage both.

Not all autopilot systems support two drives. The maker's specifications will tell you if a system can handle dual drives, and a qualified installer can advise on the best layout for your boat. For instance, Furuno's NavPilot 300 is designed for outboard vessels with one to four engines, but the drive configuration must match the steering system. Always consult the product documentation or an authorized dealer before deciding. For boats with an electronic helm, a steer-by-wire system may have its own drive requirements, so check the steer-by-wire guide for details.

Pros and cons at a glance

Here is a simple comparison of single and twin drive setups. Remember that the right choice depends on your boat's steering and the autopilot system you choose. The table below summarizes the key trade-offs.

Match the drive to your steering

The most important step is to match the drive to your boat's steering type. Raymarine's drive unit page lists drives for hydraulic, mechanical, and power-assisted steering. For example, their Type 1 and Type 2 hydraulic pumps are for different steering cylinder sizes, and their linear and rotary drives are for mechanical systems. If you have hydraulic steering, you need a hydraulic pump drive. If you have cable or mechanical steering, you need a linear or rotary drive.

The maker's specifications will tell you which drive fits your steering. If you are unsure, consult an authorized dealer or the boat's manual. For instance, Raymarine's cockpit tiller drive is for tiller-steered sailing boats, while their wheel drive is for wheel-steered sailboats. Choosing the wrong drive type can lead to poor performance or installation issues, so take the time to verify compatibility. For boats with hydraulic steering, you can see our hydraulic autopilot guide to compare pump options.

When two drives make sense

Two drives can be useful on large boats where a single drive would be too big to mount. They can also help on boats with two helm stations, allowing each station to have its own drive. Some sailors use two drives on boats with twin rudders, so each rudder gets its own actuator. But two drives are not always better. They add weight and complexity, and if the system is not designed for dual drives, you may not get the redundancy you expect.

Always check the autopilot system's specifications to see if it supports two drives and how they should be configured. For example, Raymarine's Evolution autopilot packs are designed for specific boat sizes and steering types, and the drive unit must match. A qualified installer can help you determine if a twin-drive setup is feasible and beneficial for your boat. On a powerboat with multiple helm stations, a second drive can be part of a multi-station installation; see our powerboat autopilot guide for more on that setup.

Questions to ask before choosing

Before you decide, ask these questions: What type of steering does my boat have? How much space is available for the drive? Does the autopilot system support two drives? What do the maker's specifications say about drive sizing? A qualified installer can help you answer these and ensure the system is set up correctly.

Remember that the autopilot system includes the course computer, heading sensor, control head, and drive. The drive is just one part. You can buy a complete pack that includes everything, or a core pack that leaves out the drive if you already have one. See our guides on complete autopilot packs and core packs for more details. If your boat has a sail drive or an inboard engine, the steering system may be different, so also check the sailboat autopilot guide for drive choices.

What to pick for your situation

Questions

Can I use two drives with any autopilot?

No. The autopilot system must support dual drives. Check the maker's specifications or consult a dealer. For example, Raymarine's Evolution packs are designed for specific steering systems, and not all support two drives.

Is a single large drive better than two smaller ones?

It depends on your boat. A single drive is simpler and often sufficient. Two drives can help with space or redundancy but add complexity. Consider your steering type and installation constraints.

Do I need two drives for a twin-engine boat?

Not necessarily. The drive connects to the steering system, not the engines. A single drive can steer a twin-engine boat if the steering is hydraulic or mechanical. The drive must match the steering system's requirements.

What if I already have a drive?

You can buy a core pack that includes the electronics but no drive, and keep your existing drive if it is compatible. See our core pack guide for more information.