Volvo BP1200 thruster problem

[tim.lesage@twc.com]

Last year I purchased a 2002 570 Voyager. It is equipped with a Volvo QL BP1200 24V bow thruster. Both of the switches were bad, so I was able to construct new switches for them using toggle rockers. That worked well and the thruster functioned properly last summer. The boat is on Lake Michigan in Wisconsin, so we hauled it out last October for winter storage. On the day of the haulout the thruster would not function properly. It worked well in the port direction, but would not power up at all in the starboard direction. I figured this was just a simple electrical issue due to a wire coming loose from one of my remade switch panels, but I had the mechanics check it out at my storage yard. I inquired last week as to what they found, and they tell me that they believe the motor has gone bad. As that unit is no longer in production they are uncertain whether it can be repaired/rebuilt or needs to be replaced with an entirely new thruster. I am pretty handy, so I intend to check it out myself when the weather warms up enough prior to committing to anything, but I would appreciate any advice from anyone else who has had to either repair or replace that model. I am a bit skeptical of the diagnosis, as it does not entirely make sense to me why it would function in one direction but not the other if it was due to a motor failure, but it is old so anything is possible. I have been looking at options if it does need replacement, and it appears that imtra side thruster may be a good option, looks like both the 130 kg and 170 kg models would fit in the same tube. The main dilemma I see though is that I am not sure that either of those units would fit in the same compartment. The volvo unit appears to have a right angle at the end of the shaft before it enters the tube, so my unit is installed on its side, entering the tube on the top. The imtra unit appears to be entirely vertical, so if this was installed in the same hole it would have to stand upright and would probably not fit. I clearly have to get back on the boat myself and further inspect it, but I would appreciate any thoughts from anyone else with experience in this matter.

[Viper]

There should be a directional solenoid pack that controls the direction of the motor. Sounds like one solenoid has either failed or the control side isn't firing it. I also recall the QLs having separate electronic control boxes (white), usually mounted in the engine room but could be anywhere, they'll say QL on them. You'll want to check all harness pin connections for good clean contacts.

If you have to replace the entire system, going with Sidepower through Imtra is a good choice. They're very helpful, know their stuff, and will be able to tell you exactly what you need for the conversion to suit your application. For the replacement unit, you'll be glassing over the holes in the tube from the current leg as they'll be different for the new unit. Then you'll mount the new leg on the side of the tube instead of the top so that you can motor the motor horizontally. The leg can mount in any orientation on the tube that will allow space for mounting the motor. If mounting horizontally, you'll want to fabricate a support to put under the motor.

You can also try contacting thrusterparts.com, they still have a few QL parts and are looking at adding more parts to their inventory....
http://www.thrusterparts.com/

Keep us posted.

[tim.lesage@twc.com]

Thank you for rhe response. The solenoid thing sounds promising. The control box is in the compartment with the thruster, so easy to get to. I’ll check that out along with the connections. I also will check out the wires on my controller panels that I made to replace the original ones to make sure they are not loose. Hopefully it is something like that as opposed to an entire expensive replacement. The fact that it works in one direction is what makes me question the motor failing. It should warm up enough by early March for me to start investigating.

[Viper]

I just noticed you sent me a private email the other day, it ended up in the spam folder so I didn't see it until just now. It's best to just post in the forum, I'll be sure to see inquiries that way.

As mentioned, if you have to replace the system, work with Imtra, they'll know the tube size of your QL model and will design a system based on the tube diameter you already have if the unit utilizing that diameter meets the spec for your boat model. So far every conversion I've done utilized the existing tube.

Also keep in mind that if the motor has failed, there are companies out there that specialize in repairing/rewinding motors. What you need to consider though is whether it's worth putting x amount of money into an old obsolete system who's other parts may soon fail as well.