Mostly successful docking despite runaway bow thruster

Ben Stein

Ben Stein

Publisher of, passionate marine electronics enthusiast, 100-ton USCG master.

10 Responses

  1. Tim C says:

    Been there, done that except my port engine remained in gear as my engine controls failed and the manual backup would not move out of gear. Shut off the engine but could not stop drift into dock. My wife is very good about telling dockhands to get a line on a cleat as many think they can control or push our 62-foot boat around by holding a line. Not going to happen. They don’t seem to understand the leverage gained with one wrap on a dock cleat. Unfortunately, the dockhands were deer in the headlights. If they would have done as told the lines would have slowed or stopped our forward progress. Lesson learned but it is a helpless feeling.

  2. Bob Shircliff says:

    Good morning, Ben. Sounds like you did a great job in battlefield conditions! On our 64′ Grand Alaskan, we have an “Off” switch at the controls for our bow and stern thruster. Maybe there is a control panel that would give you the ability to quickly turn the system off. Was there not a breaker on your DC panel that could have been shut off?

    • Ben Stein Ben Stein says:


      I do have an on/off switch at the helm but that only turns the control system for the thruster on and off. It’s not a battery disconnect and in this case, that’s the only thing that would have shut down the thruster. Because the solenoid was stuck, the control system had been defeated.

      Also, large loads like thrusters and windlasses typically don’t have breakers on the main DC panel. They may have a large, plunger-style breaker near the panel or just T-class fuses and a battery switch in the engine room (that’s what I have).

      So, my only choice was to spring to the engine room from the fly bridge. With the winds and close proximity of other boats the engine room seemed awfully far away.

      -Ben S.

  3. John Pitney says:

    Been there, done that #2 – Same boat (53′ version), same thruster, same fused solenoid, – only our incident happened while “floating” in old Lock 52 on the Ohio River in the middle of a lock-thru. Luckily we were the only boat in the lock at the time and had been told by the lock master to just “float in the middle” during the process. Was using the bow thruster to keep the bow straight in the lock when it stuck ON in the stbd position. My wife was in the cockpit and had few panicked words over the headset (“What the hell are you doing??”) as we rotated around perpendicular to the lock. As I recall, no amount of joystick movement had any effect. I finally made a mad dash to the ER and turned off the breaker. LIke you, I found enough nameplate data on the solenoid to identify the manufacturer and replaced it for much less than a BOAT unit. Not sure what PM could be done other than making sure all the cable connections are secure and clean to prevent this, but it looks like a pretty common failure. Also experienced the same boat bite on the swim platform corner in other incidents on that boat. We finally rigged a deflated ball fender (about 18″ diam) with one side pushed in to form kind of a bowl shape that offered some protection to those very fragile corners. The order was “rig the bra fenders”. Regardless, we thoroughly enjoyed the 12 years we owned our Voyager 530. It was a great – Great Loop boat!

    • Ben Stein Ben Stein says:

      Very interesting to hear about the same failure on the same boat.

      There’s no question the swim platforms on these boats are pretty fragile, especially considering the platform is the widest portion of the boat and hangs out there quite vulnerable.

      -Ben S.

  4. Brad Arrington says:

    Maybe you could rig a Blue Sea Systems remote battery disconnect switch. My boat (a Back Cove 37) uses these for all the batteries and main functions: house bank, engine bank, generator, and each thruster. The actual Blue Sea battery disconnects are in the engine space, with the remote switches on the starboard bulkhead at the helm. My former Back Cove 34 had a very similar setup with the battery disconnects just inside the cabin and 1 step from the helm. Very handy!

  5. Donald Joyce says:

    We have the same contactors on our sailboat for hydraulic motor control. A contactor welded shut and unbeknownst to me kept the intermittent use high power 1000W 24 VDC motor running to the point it got very very hot and caused a minor fire. I replaced the contactor and the motor and since then, I service the contactors every season to make sure they are in good condition. I also installed additional high power breakers I can manually trip to cut power to the motors should a welding occurrence arise. The sad truth is that contactors used for DC applications are prone to welding closed.

  6. Orin Guidry says:

    Thanks for the story and comments. My boat also has breakers for the thruster motors at the helm. However in a run away situation, I might not have had the presence of mind to shut off power at the breaker.

    This story now makes me more aware of the solution if the problem occurs on my boat.

  7. Bill Kearney Bill Kearney says:

    This reminds me I should probably get better acquainted with the power circuits for our bow and stern thrusters. There’s not a shut off or breaker for either of them in an immediately accessible location.

  8. Nigel says:

    Hi, thank you Ben for the article and the good comments from others.
    My Cheoy Lee Offshore 41 (1980) is currently on a mooring in Pittwater, Sydney. I run the motor every couple of weeks and give the windlass and thruster, a Max Power, a spin.
    Last time I did, a couple of days ago, the thruster kept pushing to port no matter what I did with the, no name, lever. Surreal, spinning around, and so glad I was not entering a marina etc, sounds like most of you who were managed very well!
    Then the thruster stopped.
    After the event, I found the battery selector switch had burnt out. The fuse for the thruster, in the bow, was intact. The on/off switch for the thruster is also in the bow and, as usual, under berths piled with sails etc.
    Ok, it is an old boat. But clearly I need to improve the system. You and your commentators offer lots of good knowledge and advice. Nigel

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