The autopilot drive that fits your boat is set by your steering system: hydraulic steering takes a hydraulic pump, mechanical steering takes a linear or rotary drive, and steer-by-wire boats take a dedicated pack. After the steering type, the manufacturer's limits on cylinder volume (hydraulic) or boat displacement (mechanical) pick the size of the drive.
This guide is brand-neutral. It starts from your steering, then shows the limits that Raymarine, Garmin and Lewmar publish for each drive type, and links to the systems we carry. For the Raymarine Evolution range in detail, see our Raymarine autopilot guide.
Autopilot drive types at a glance
| Your steering | Drive type | What the manufacturers publish |
|---|---|---|
| Hydraulic | Hydraulic pump | Raymarine Type 1 pump: steering ram 80-230 cc (4.9-14 in³). Garmin SmartPump v2: total cylinder volume up to 24 in³. |
| Mechanical, boat up to 11,000 kg | Linear or rotary drive | Raymarine Type 1 linear and Type 1 rotary drives: up to 11,000 kg (24,000 lbs) displacement. |
| Mechanical, larger boat | Type 2 or Type 3 drive, or Garmin Class A or B linear actuator | Raymarine Type 2 rotary: up to 20,000 kg. Garmin Class A: up to 28,500 lb. Class B: 48,000 to 79,000 lb. |
| Chain, gearbox or lever steering | Lewmar rotary sprocket, Mamba or Direct Drive unit | 1/8 hp to 1 hp, 12 V or 24 V, depending on the model. |
| Steer-by-wire | Dedicated autopilot pack | Garmin Reactor 40 steer-by-wire packs, matched to the steering system. |
Limits come from each manufacturer's own pages and documents, and each one measures its own way. Always check the limits for your exact model before you order.
What kind of steering does my boat have?
Look at what connects your wheel or tiller to the rudder. Hydraulic hoses and a steering cylinder mean hydraulic steering. Cables, a chain or a steering gearbox mean mechanical steering. If there is no mechanical link at all, only electronics, it is steer-by-wire. That answer decides which row of the table applies to you.
Which autopilot drive fits hydraulic steering?
A hydraulic pump, sized to the volume of your steering cylinder. Raymarine sizes its pumps by steering ram capacity:
- Type 1 pump: 80-230 cc (4.9-14 in³), as in the Evolution EV-200 Power Pilot, which Raymarine describes as an autopilot for medium to large powerboats with hydraulic steering.
- Type 2 pump: 230-350 cc (14-21 in³).
- Type 3 pump: 350-500 cc (21-30.5 in³).
Garmin sizes by cylinder volume in cubic inches. In its autopilot reference table, the Reactor 40 with SmartPump v2 covers total cylinder volumes up to 24 in³ and is the option Garmin recommends for high use, rougher water and slow speeds. The lower-cost GHP 1.2L pump suits single-cylinder systems of 6 to 14 in³, and the GHP 2.0L pump suits dual-cylinder systems of 10 to 24 in³.
Find the cylinder volume in your steering system's documentation, then pick the pump that covers it. We carry these hydraulic options:
- Raymarine EV-200 Power Hydraulic Evolution Complete Autopilot System
- Garmin Reactor 40 Hydraulic Autopilot with GHC 50
- Navico Pump-2 MK2 Reversible Hydraulic Autopilot Pump, 12V and Pump-3 MK2
- Octopus pumps by cylinder size: Type 1 (up to 15 CI), Type 2 (up to 18 CI) and Type 3 (up to 30 CI). See our Octopus autopilot guide.
Which autopilot drive fits a mechanically steered sailboat?
A linear or a rotary drive, chosen by your boat's displacement. A linear drive pushes and pulls an arm on the steering, and a rotary drive turns a shaft or sprocket. Raymarine's published limits:
- Type 1 linear drive: mechanical linear drive for boats up to 11,000 kg (24,000 lbs) displacement. The EV-200 Sail Pilot uses it for mechanically steered sailboats.
- Type 1 rotary drive: electric rotary drive, also up to 11,000 kg (24,000 lbs).
- Type 2 rotary drives: up to 20,000 kg (44,000 lbs).
- Hydraulic linear drive systems for mechanical steering: Type 2 up to 22,000 kg (48,000 lbs) and Type 3 up to 35,000 kg (77,000 lbs). Raymarine lists these as compatible with the ACU-400 actuator control unit, while the ACU-200 works with Type 1 drives.
Garmin's reference table sizes its Reactor 40 mechanical corepack by total vessel displacement: a Class A linear actuator up to 28,500 lb with very low steering drag, a Class B compact linear actuator up to 48,400 lb, and a Class B linear actuator for 48,000 to 79,000 lb. For sailboats that already have a non-Garmin drive unit, the same corepack is listed with a third-party drive, plus a GRF 10 rudder sensor.
Systems we carry:
- Raymarine EV-200 Sail Linear Drive Evolution Complete Autopilot System
- Garmin Reactor 40 Mechanical/Retrofit/Solenoid Corepack with GHC 50
What are Lewmar rotary sprocket, Mamba and Direct Drive units?
They are Lewmar's three mechanical autopilot drive families, each with its own installation guide, and all three come in 12 V and 24 V versions — for example the Lewmar Rotary Drive Unit 5/8P - 9T (1/4 hp - 24V).
- Rotary sprocket drive: connects to the steering by chain and sprocket, in the 5/8P sprocket pitch Lewmar lists for these units, from 1/8 hp to 1 hp. Example: Lewmar Rotary Drive Unit 5/8P - 9T (1/4 hp - 12V).
- Mamba drive: mounts on the bevel head or reduction gearbox of the steering system through an interface plate, in Standard and Compact versions from 1/8 hp to 1 hp. Example: Lewmar Mamba Drive Unit Std (1/4 hp - 12V).
- Direct Drive: acts through an output lever with 166 mm or 134 mm centres, from 1/8 hp to 1/2 hp. Examples: Lewmar Direct Drive Unit 166 mm OL (1/4 hp - 12V) and Lewmar Direct Drive Unit 134 mm OL (1/4 hp - 12V).
The full range is in the Lewmar autopilot drives collection. Match the drive to how your steering is built, and use Lewmar's installation guide for your model to confirm it fits.
What about steer-by-wire and solenoid systems?
With steer-by-wire there is no mechanical link to drive, so the autopilot talks to the steering system electronically. Garmin lists a standard Reactor 40 steer-by-wire corepack for SeaStar Optimus, ZF pod drive, Yanmar and Evinrude G2 systems, and separate packs for Yamaha Helm Master, Volvo Penta and Viking Viper. Our option is the Garmin Reactor 40 Steer-By-Wire Standard Corepack with GHC 50. For hydraulic systems with a constant-running pump and solenoid control, Garmin lists the mechanical/solenoid/retrofit corepack with a third-party solenoid.
Which autopilot systems do we carry?
Browse the whole range in Autopilot Systems, or by brand: Raymarine, Simrad, B&G and Lewmar drives. Simrad and B&G core packs and controllers are there too. If you want to know how an Evolution system works without a chartplotter, read our explainer.
Frequently asked questions
What is the difference between a linear and a rotary autopilot drive?
A linear drive moves in a straight line, pushing and pulling an arm on the steering. A rotary drive turns a shaft or sprocket. Lewmar's rotary sprocket drive, for example, connects to the steering by chain.
How do I choose the size of a hydraulic autopilot pump?
By the volume of your steering cylinder. Raymarine states its pump ranges in cc (Type 1 80-230 cc) and Garmin in cubic inches of total cylinder volume (SmartPump v2 up to 24 cubic inches).
Does a bigger boat need a bigger autopilot drive?
Yes, for mechanical steering. Manufacturers set drive limits by displacement: for example Raymarine Type 1 drives up to 11,000 kg and Type 2 rotary drives up to 20,000 kg.
Is the drive included in the autopilot pack?
It depends on the pack. Raymarine sells Evolution packs with a drive and without one, for owners upgrading an existing Type 1 system, so check the product title.
Can I use a Garmin Reactor 40 with a drive from another brand?
On sailboats with mechanical steering, Garmin's reference table lists the Reactor 40 mechanical corepack with a third-party drive unit, plus a GRF 10 rudder sensor. Confirm the combination with Garmin before you order.
You may also be interested in
- Raymarine Autopilot Guide: Evolution Series, Components & Drive Selection
- Which Octopus autopilot should you choose for your sailboat?
- How does Raymarine autopilot work without chartplotter?
Written by the MAURIPRO Electronics Team. Limits and specifications are from Raymarine, Garmin and Lewmar product pages and installation documents.
Last updated: October 20, 2026.