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  • Bill Kinney

Updating the Amel Bow Thruster

The bow thruster that Amel designed for the Super Maramu and similar boats was far ahead of its time. It is still one of the best out there. On any bow thruster there are a couple of design considerations that conflict. You want a thruster that is as far forward as possible to have the best turning moment, but at the same time you want it as deep underwater as possible so it doesn't suck air into the propeller when it is running. Amel's solution to this was to have the unit drop down out of the hull when in use, and then retract, flush into the hull, for sailing.


There are three major mechanical parts to this bow thruster. The main electric motor, the linear actuator that lifts and lowers the unit and the retractable shaft and propeller. The main electric motor and the actuator were standard industrial parts. while the shaft and propeller were made by Amel, and are still available from them.


The main drive motor is no longer available from the original manufacturer, but there are alternative sources if needed. Usually, electric motors can be rebuilt and serviced almost forever by a skilled rebuild shop. But if your motor has gone to the great bow thruster in the sky and can't be rehabilitated, contact me. We might be able to help you get something that will work for you.


Several different suppliers were used for the actuator, and some of these have been out of business for some time, so the identical part can be impossible to find. I have found and specified a linear actuator that is a significant improvement on the original ones that Amel used. It is technologically more sophisticated than the original. All of the control circuits needed are built in, so the bespoke control box and limit switches designed by Amel are no longer needed. This greatly simplifies the wiring and makes long term maintenance easier, and it is available for lower cost than the replacement from Amel.


In addition to the more sophisticated internals, it is far more robust, and better suited to installation in a location where humidity and salt water are likely. It is sealed to IP69 standard, and survives a 500 hour salt water spray test. No longer will a minor leak at the thruster shaft have the potential to cause serious corrosion damage to the actuator. There is even the ability to manually operate the unit with a standard ratchet wrench in the event of an electrical system failure. The actuator is maintenance free, and no lubrication or service is required other than an occasional rinse with fresh water to remove any accumulated salt and dirt. External parts are stainless steel, aluminum, and plastic. Amel always chose the best components they could source, this is the actuator that Amel would use if they were designing this today!


Installation of this new unit requires minor changes in wiring. The control circuit is upgraded to ensure that the thruster can not operate unless it is fully lowered. All other functions of the system are retained as originally designed, including the lights and buzzers at the helm indicating the status of the unit.


Contact me, and I can arrange for getting you one of these units with detailed installation instructions, or if you are nearby, I can install one for you.

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