At the start of the 2021 season in Cherbourg, as we were ready to depart in one of our narrow weather windows for a night ride to Aber-Wrac'h, I had the nasty surprise as we were leaving the cat-way under serious wind that the bow-thruster did not respond to my attempts to use it.
Trying it before freeing the mooring lines will be on our departure checklist now on! But what happened to it?
My bow-thruster is a Side-Power SE 100/185T, considered as highly reliable. I had it in operation for 6 years without any problems, but I noticed that it was producing quite a bit of carbon dust in operation. My first visual inspection noticed immediately that the size of the eight carbon brushes was very different, and therefore I got new carbon brushes that we changed them with a service man. You can see on the picture below that four of the brushes had kept their original size, meaning they were seized-up in their casing and therefore not functioning. When fitting the new carbon brushes, we ensured that they were able to move very freely in their casing. To that end, we cleaned the casings with an old toothbrush and WD40, and then sanded a bit the side of some of the brushes that were not moving completely freely.
But this was not sufficient to get the thruster to function correctly. We then went through all the steps listed in the troubleshooting guide on the web (see link below), which proved to be very easy to follow, using a structured approach to identify the origin of the problem.
We rapidly came to the conclusion that the issue was that the two solenoids activating the rotor in either directions were stuck. As per the instructions, we bypassed every control panel and plugged directly the solenoids on the batteries. And this was sufficient to unblock them. The thruster started to function a bit erratically initially, but after a dozen attempts, it started running as smoothly as before.
I will change them anyway, as I am on my way to the Mediterranean, and handling the boat without a bow thruster in crowded marinas with strong winds over the past few weeks has proven to be quite stressful.
Lesons learned:
- Check the bow thruster operations before freeing the last mooring line upon departing
- Two solenoids can get dysfunctional at the same time, in particular after wintering the boat for 8 months
- The documentation available for the Side-Power thrusters is impressive and allows to make a very precise diagnosis of the problerm
- You should not loose trust in your thruster!
Thanks a lot !
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