Jefa Steering Sprocket Autopilot Drive - 200Nm, 12V

Overview

The Jefa Steering Sprocket Autopilot Drive is a compact, high-torque drive unit based on the renowned Jefa 200Nm sprocket drive. Designed specifically for wheel-steered sailing yachts from around 30 to 50 feet, it delivers powerful, precise and highly efficient autopilot control through a chain and sprocket mounted on a rotating steering shaft.

With a maximum output torque of 200Nm (equivalent to approximately 40kg on the rim of a 1m wheel) and a weight of only about 7kg, this drive offers an excellent balance of performance, reliability and low power consumption – ideal for modern cruising and bluec water yachts where electrical efficiency matters.

Key features

• 200Nm rated output torque for yachts up to roughly 165KgM rudder torque
• Suitable for sailing yachts around 30–50 feet with cable or rod steering systems
• Extremely compact form factor (approx. 241mm long, 178mm max diameter) for tight installations
• Continuous-duty design for 24/7 operation in demanding offshore conditions
• Highly efficient flat-wound “pancake” electric motor with excellent starting torque and fast response
• Three-stage planetary gearbox for smooth, quiet and efficient power transmission
• Integrated electro-magnetic clutch for safe, automatic engagement and disengagement
• Designed to work with a secondary sprocket on any steering shaft with rotary motion
• Compatible with most major autopilot computers from the leading electronics brands

Compact, efficient drive unit

Space is always at a premium on a modern sailing yacht, especially around the steering system. The sprocket drive uses a short, cylindrical housing that can be tucked into tight lockers or under-cockpit spaces, while still aligning directly with the steering shaft.

The dedicated flat-wound motor is optimised for high starting torque and quick response to autopilot commands. With motor efficiencies around 72.5%, more of the electrical energy is converted into useful steering work, helping to keep average current draw low and battery charging times to a minimum.

Three-stage planetary gearbox

To achieve the correct combination of rudder speed and torque, the sprocket drive uses a three-stage planetary gearbox with a total reduction of 486:1. This design offers several key benefits over traditional worm or spur gear arrangements:

• Very high mechanical efficiency for lower power consumption
• Torque and loads shared across multiple teeth, allowing a compact but strong gearbox
• All forces remain on the centreline of the drive for reduced housing stress and long-term reliability
• Smooth, controlled output ideal for accurate autopilot steering in difficult sea states

Electro-magnetic clutch for safe manual steering

When you take the helm manually, the drive must disconnect cleanly from the steering system. The integrated electro-magnetic clutch is controlled by the autopilot computer and uses a patented pin-based engagement system on the outer gear ring of the final planetary stage.

This arrangement offers:

• Very low back-drive friction when hand steering
• Low power draw (approx. 1.4A at 12V when engaged)
• No wear-prone friction plates, so clutch performance remains consistent over time
• A more controlled handover: the helmsman loads the wheel before disengagement, avoiding sudden surprises from full rudder torque

When the autopilot is switched off or the clutch is not powered, the drive is disengaged by default, making it a fail-safe solution.

Steering performance and hard-over time

The sprocket drive is designed to deliver an ideal hard-over time (rudder moving through about 72°) of around 12–15 seconds, depending on the sprocket sizes selected for the steering shaft. This gives a responsive but not “nervous” autopilot, and most modern control units can fine-tune the effective speed using pulse-width modulation.

By choosing the correct ratio between the drive sprocket and the steering-shaft sprocket, you can:

• Avoid an over-reactive pilot that hunts from side to side
• Ensure the pilot remains powerful and responsive enough to steer in heavy seas and when heavily loaded
• Optimise performance for your particular steering geometry

Upffront can supply matching stainless steel sprockets and chain to suit your installation.

Autopilot integration and compatibility

The sprocket drive has been designed to work with all major autopilot brands and their appropriate drive output stages. Typical 12V systems include autopilot computers from:

• Garmin
• Raymarine
• B&G
• Simrad
• NKE

Electrical connection is straightforward:

• Two small-section wires for the clutch, connected to the autopilot’s clutch output
• Two heavier-section wires for the motor, connected to the drive output terminals on the autopilot computer

Once wired, engaging the autopilot on your control head automatically energises the clutch and hands steering over to the drive.

Installation and mounting options

The drive is suitable for any mechanical steering system that uses a rotating shaft (cable or rod). A secondary sprocket is fitted to the steering shaft and driven via a 5/8" stainless steel chain from the autopilot drive.

For installations where the drive cannot be mounted on a surface parallel to the chain, an optional mounting bracket is available to allow flat mounting while still permitting accurate chain alignment and tensioning.

Accessories and related components typically include:

• Stainless steel sprockets in various tooth counts, bored and keyed to suit your steering shaft
• 5/8" non-magnetic stainless steel chain and master links
• Dedicated mounting bracket for sprocket drive installations

Ideal applications

The Jefa Steering Sprocket Autopilot Drive – 200Nm, 12V is an excellent choice for:

• Bluewater and ocean cruising yachts that demand reliable 24/7 autopilot operation
• Performance cruisers needing a compact, efficient drive that fits into tight steering compartments
• Owners upgrading from lighter-duty drives to a more robust mechanical solution
• New builds where a rotary steering shaft and chain drive are the preferred integration method

By combining high torque, compact dimensions and outstanding efficiency, this sprocket drive provides a robust and future-proof solution for serious cruising sailors who depend on their autopilot as an essential member of the crew.