Options for a weak Thruster

[PMF1984]

Reread the original post. Now not sure about the problem. Is it “no difference” with the new prop, or “doesn’t work”?

I have the same thruster on a Pilgrim, and really these are not really effective on a windy day, or against a strong current. Your wire size is good. If the thruster is providing no thrust, then I suggest checking out the shear pin.

 

[Transaxial]

All great points above. After checking the contacts, I’ll probably do the local battery thing to punch up the delivery of juice, but maybe I should have mentioned that it worked reasonably well (not great) in the past. Then came the haul out, bottom job, and then the painter didn’t re-pin the prop, so it spun off on the first use. Then I ordered the replacement 6 blade (vs. original 3 blade) prop. It’s been weaker ever since. I should probably add that the motor doesn’t overheat on long applications. Just out of curiosity, I ran it for a whole minute without throwing the heat breaker.

I looked back through the thread for the size of tube you have but didn't see it. I am assuming you have a 185 mm ID tunnel? I just pulled up one of the first brands that popped up - Sidepower and they have lots of models for the 185 tube. If you can't make yours perform there is a 8.4 HP model for your tube that runs on 24 volts. That would be a good chance to upgrade your system to run on the higher voltage which effectively doubles the current carrying capacity of your existing wire by simply hooking your two 8D batteries in series. Specs on the SE100/185T - 24V are: Thrust at 21 V 220 pounds, Power at 21 V 8.4 HP, Rated for 35-55' boat, Tunnel ID 185 mm, Twin props. The specs are very close to the same for a 12 V model but your 19' each way cable run would work better on 24 V.

I am just interested in thrusters because I recently did the research and bought and installed a MaxPower hydraulic - CT HYD 125 for my 39' Palmer. I went for the highest cc/rev model because it runs at much lower pressure, 2200 psi and higher volume, 9.25 gpm and I sized my pump to match at 1200 engine rpm. It was rated at 12.5 HP or 9.3 KW and 260 pounds of thrust. The reason I am commenting is because I was a little disappointed that it does not have more push even though it is rated for 35 - 60' boats. Maybe it is my 5 1/2' deep keel that creates resistance. Although I am not impressed with the power, I like the fact I can idle my engine down to slow idle and have very gentle and quiet thruster operation when in calm water. Don't get me wrong, it works great at slow speed, but I don't know if it will have enough power in strong current and/or wind. It is one of those things where more IS better I think. I was just curious if it was possible to buy a more powerful motor and prop for your 185 mm tunnel. Good luck with your project.

 

[Comodave]

Check post #21 about my Sidepower. I have the 8 hp one with the 185 tunnel. It works really well moving my stern which has a lot of windage.

 

[Transaxial]

Check post #21 about my Sidepower. I have the 8 hp one with the 185 tunnel. It works really well moving my stern which has a lot of windage.

Yes I got that from your post and glad it works well for you. My suggestion was for the OP to replace his old motor and gearbox with a new one, possibly like yours if it fits in his tube. They do have motors for smaller tubes but with less power.