My stern thruster stopped working so I removed my bow thruster


As I mentioned in a previous post, my stern thruster stopped working right at the end of our New Year’s trip. My suspicion was that the brushes needed cleaning (the thruster is now 10 years old). I did some research and decided this was something I could tackle myself. The manufacturer (Imtra/Side-Power) has some really good instructions on their web site (send me an email if you need them). I went down to the boat ready to tackle this project, hoping I wouldn’t break anything.

The first thing I did was test the stern thruster to see if it magically started working again.  Well, hocus-pocus and abracadabra it worked! Deciding what to do next, I factored in that, over the past few years, my bow thruster had become noticeably weaker than the stern thruster. So, instead of pulling the stern thruster, I decided to do the bow thruster first to see if cleaning the brushes really does make a difference in performance.  Also, the bow thruster was a little easier to get to.

Removal was relatively straight forward and I did double-check that it’s OK to remove the thruster motor while the boat is in the water. Also, be sure to disconnect the power before removing any wires. The unit weighs about 40 pounds so you need to be ready for that weight as you remove the last mounting bolt.

Bow thruster motor

Bow thruster motor

I took the unit home to clean the brushes. I used a can of compressed air in the garage to do a first pass at blowing the carbon dust out and then followed the instructions for removing and cleaning each brush. I did this part inside on a small table so I could have better light (but don’t tell my wife!)  The whole process only took about an hour.

Bow thruster brushes ready to be removed and cleaned.

Thruster brushes ready to be removed and cleaned.

I put it all back together, making sure that I didn’t disturb any of the wire connections. I took it back down to the boat today and the re-install went very quickly. I turned the thruster power back on and crossed my fingers that it would work. I pushed the controller to port and from my normal spot up on the bridge I could immediately hear and feel the difference–it’s definitely stronger than it was before. It worked in both directions so it looks like I didn’t break anything. Success!

Below is a short video showing the thruster in action both before and after the brushes were cleaned. Note that I incorrectly say “stern thruster” in the second half of the video…it’s the bow thruster, of course.  🙂


I guess only a boatnut would end up removing the bow thruster when the stern thruster was the one that was acting up. If you have a thruster and want to try cleaning the brushes in the electric motor, please feel free to contact me with any questions you have…I’m happy to help!

Happy Boating!
-Boatnut Brian


January 23, 2016 |

3 thoughts on “My stern thruster stopped working so I removed my bow thruster

  1. Michael 516-967-2508 says:

    I just found your article online about removing the truster,congrats i attempting it also. I have questions, can we talk?


    Hi, I am trying to remove the electic motor off my stern thruster but after disconnecting all electric wiring and the 4 mounting bolts, I cannot pull of the motor as if there is something stoping it from sliding off the shaft.
    Can you suggest what is stopping from sliding off?

    • Brian says:

      Hi Jack, I did this about 6 years ago and I don’t remember running into any trouble getting the electric motor off. You might try some searches on YouTube. I had found a great forum post on the Meridian Yacht Owners club that guided me through the process with many photos. Good luck!

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