Propulsion System - Motors, Gears, etc


Hi Kappertz, could you tell us were did you find those parts?


Hi Semih, the correct size is nema 23, that is the same of the Parker PV40TN, and there are a lot of them at Ebay.
About the durability, I don’t know.


It’s from the german company MHz:


Hi Kappertz,

That looks like a great design you made for the jet mount, would you be willing to share your STL file?

Thank you,

Phil Kite
Alberta, Canada


Sure, I can share it. There’s one problem though: in my first design, the water inlet was way smaller. In an attempt to improve thrust, I over did and now you can slightly twist the jet mount against the base (at least when printed with SLS). The optimum design is somewhere in between. Maybe I should rather post the upcoming version 3.



Hi Boris,
is it working? Are you testing? Tell us more, please.


The engine is too slow 6-7 km / h on 12v, 500w


Thank you. This result is no surprise to me if the motor is still in original condition. I own similar trolling motors (up to 1450 W, for use on boats). The usual rpm and the propeller pitch prevent a higher speed. But I think, a different setup could be successful, because there are types in the needed power range.


I have wanted to try this!
Could you try changing out the propeller and getting a little more horsepower out of it?


I opened the engine to see if there was a gearbox but there was none. I can try at higher voltage. What propeller would you offer?



Pacificmeister has some CAD files on good Propellers Pacificmeister Build Info and CAD Sources

I think this one might work too.


Hello! Do you think how much thrust has a jet pump with a 40mm propeller? 1200w will they suffice?


You need at least 2x 50mm 2000w each imho


probsbly like 8-10 kg max


Seen this 120kv. Waterproof.


Looking at the PM-build; what do you do to prevent waterleaks between the lipseals and the printed plastic part called “Seal mount”? Seems to me that the somewhat rough 3d-printed surface will seal badly against the outer side of the lipseals? Do you sand it? Silicone it? What do you say…


Available from Aliexpress for 350USD+ 40USD shipping -
not bad, eliminates need for almost everything else, except mast clamp and - if you want it - Prop-guard.
On the other hand it has 75mm diameter (more with mast-clamp) so it will have higher drag and it will probably need 14s and up; last not least it is heavier than Pacificmeister’s design.
Still, I like it :slight_smile:


Definitely interested in hearing feedback if anyone tests one of these motors.