3rd party mechanical drive unit for Autopilot

[Derek - Raymarine - Moderator]

Installing Raymarine Autopilot electronics to existing old Raymarine mechanical Drive unit or 3rd party autopilot mechanical drive unit.

Some vessels already have a pre-existing drive installed to the vessel's steering system and provided it is in good condition, operating smoothly and efficiently and is reliable, it most likely can be used with current Autopilot electronics.

If the drive is mechanical, it must use a reversing electric motor and have an electromagnetic clutch.

To be certain that the Autopilot ACU will operate the drive reliably it is important to know the max and average current draw of the motor in the drive unit, since 3rd party drives can take large slugs of current when starting and stopping and we need to make sure that this will not damage the ACU. The ACU400 is the largest Actuator Control unit and will handle a maximum transient start-up current of 60Amps with a maximum continuous current of 30Amps.

The current draw will increase depending on the boat displacement and the weather conditions, remember that frequent motor reversals in adverse weather or with a poor installation will boost temperatures, boost current consumption and possibly lead to premature failure.

The clutch maximum current support by the ACU400 is 3Amps and can be either 12v or 24v, this is selectable on the ACU400

We would recommend fitting a rudder angle transducer to accurately measure the rudder position and to help control the duty cycle of the Autopilot. It is useful to note that increasing the RUDDER DAMPING in the autopilot calibration will reduce the motor instability in installations where the drive 'oscillates' to and fro and hence reduce the heat, current consumption and system wear and tear.
Check here for more details about the importance of rudder damping


For more information on testing the drive units click here


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