Need a new bow thruster?

[adventure seeker]

Hi I am new to this boat.The Side Power bow thruster works, but blows the breaker after about 4-5 seconds.
It was never (since 1993) wired with the correct gauge wire. I have re-wired it with the recomended wire gauge, 2-0, and it is a little better then it was(goes 4-5 sec. instead of 1-2 sec.)
For me, with a single screw, I often blow the breaker when docking and then I'm really F***ed. When I got the boat it had a 300A breaker which is still in use and way to high, like a penny in an old fuse.
So I have to believe the thruster or motor must be the problem. Any other thoughts would be appreciated.
Can the components be re-built or must they be replaced? Can I use different oil instead of the 90w? Thanks for your help,

 

[Xlantic]

You may want to check what the power draw for your thruster should be and also check the current flowing when the thruster is in use. The first you can check in the manual or maybe a plaque on the motor. The second you can do with the right multimeter which you can buy or borrow.

If the thruster is drawing more power than what it was designed for then there is something wrong with it. If not, your breaker may be the problem.

 

[Roughnit]

I agree you need to check what model you have and check what amp draw you should be expecting. A quick search shows that all but their smallest current thrusters draw more than 300 amps (at least for 12 volt units). My bow thruster is much older from a company that is out of business and is only 100lbs of thrust but it requires more than 300 amps to operate. It has a 5 hp motor, 5hp is about 3700 watts or 308 amps at 12 volts not accounting for any inefficiencies or the voltage drop at the battery when drawing high amps.

 

[adventure seeker]

I'm not at the boat now, but will check when I'm back next week. It does have a 6hp motor.

 

[psneeld]

300 amps does not sound like a penny in a fuse holder to me for a thruster...they are often the equivalent of a starter or windlass motor.


Double check before blaming the wrong things.

 

[Comodave]

Whenever I wire something I always go one size larger than recommended. It saves lots of issues down the road and things work better with good voltage. You need to check with Imtra, SidePower distributor, and see what your thruster is supposed to draw. Then go to a size cable, or larger, capable of supplying that current. Put in a breaker or fuse that is proper for the cables. Then check every connection and make sure they are in good condition. I use a copper conductive paste, like CopperShield by Thomas and Betts, on the cables before putting on the closed end connector. Then cover with adhesive lined heat shrink. Check the voltage on the motor when the thruster is operating. Good luck.

 

[AlanT]

While you are working on this you should also check the brush assemblies. These were a source of trouble on a prior boat with a Sidepower thruster. When the thruster was over-worked it burned the brushes (I think) and they needed to be replaced. You should pull them out and check them and they may only need cleaning up. Mine was under warranty so I did not do the work myself and therefore am a bit sketchy on the details. ~A

 

[Roughnit]

I'm not at the boat now, but will check when I'm back next week. It does have a 6hp motor.

6 hp is approximately 4500 watts so even if you can supply a full 12 volts to the motor it is drawing 375 amps makes sense your blowing the breaker. I think side-power rates their thruster at 10.5 volts so could be drawing closer to 430 amps based on voltage drop. They also have specifications for minimum CCA wire size etc. I found side power (Sleipner) to be very responsive to technical questions when I was considering replacing my current thruster (my email went to a tech or engineer not a salesman), so even if you don’t have the original manuals I’ll bet they can answer any questions.