electric transmission disengagement clutch

Jefa series 100 & 200 electric transmission disengagement clutch.
The Jefa disengagement clutch offers the possibility to disengage the transmission steering system from the rudder with a power consumption of only 0.7 amps (12 & 24 volts). There are good reasons to do so:
1). Lower power consumption of the autopilot drive unit. As the steering wheel(s) and transmission parts don't have to be speeded up and slowed down which each autopilot correction.
2). Less wear in the steering transmission parts. On most blue water cruisers the autopilot is steering the yacht the vast majority in time.
3). More safety in the cockpit. The wheel(s) will not rotate randomly any more under autopilot cruising and there is no risk to get hands and arms trapped in the spokes, especially when there are kids on board.
4). On twin wheel boat you can disengage one wheel and steer on the other so you don't have the annoying "echo effect" - when you do a quick rotation on one wheel, a second later you feel the echo from speeding up and slowing down the other wheel.

Please click on the picture for a larger view.

Main dimensions:

Mounting limitations:

This illustration shows the minimal length needed to integrate the electric clutch into the transmission system.

This illustration shows the integration of the electric clutch into the transmission system.

The construction:

The above cross section shows the construction of the electric clutch. Under normal power off circumstances (as in the above illustration) the clutch pin, which is connected to the right shaft, is connected to the left flange and shaft. All forces are now transmitted through the unit with a neglectable amount of friction and play.
As soon as the unit is powered, only 0.7 amps (12 & 24 volts) is enough to disengage the clutch pin. Both flanges are now not engaged any more so the right shaft can rotate independently from the left.

Configuration: The electric clutch should be operated by a seperate button near the pedestal and should not be automatically switched by the autopilot. Standard the electric clutch has one clutch pin hole, so there is only one engagement position in 360 rotation. The advantage is when the steering wheel has a mark for the amidships position, after disengaging, the steering wheel will always come back in this position. The disadvantage is that it could take a small while to find the engagement point. Especially in a panic situation, it could take a while before the mechanical steering is engaged again.
The solution for this would be to order the unit with 6 engagement points (every 60). This way it will be much easier to find the engagement point. To set the wheel in the amidships position could be done while cruising slowly without sail or engine drive, disengaging the steering, rotating the wheel with the mark upwards and engage again.


Jefa electric transmission disengagement clutch 

Part No.


Price in Euro


Electric clutch for type 100 transmission systems 12 volts



Electric clutch for type 100 transmission systems 24 volts



Electric clutch for type 200 transmission systems 24 volts


Service information:
Please click the left picture to open the electric clutch drawings with parts list.