Wisconsin Build Finally Coming Together

Hello All!
I was planning on waiting till my build was complete to post pictures, but after a year of slow progress I’m just going to make a post to get opinions/recommendations.

I hope to have the rest of the motor parts completed this week as well as:

  • Seal the battery cavity in the board
  • Weld Motor-to-Mast mount onto the mast
  • and a grocery list of other stuff most likely

Might not happen as soon as I would like since I’m currently in the process of rebuilding my uncles Jet-Ski engine. But no harm in being optimistic!


Very nice , I would have put the plate between the mast and the box this other way :wink:

I think you did that because of the holes in the board , in that case , for the strength : use the one at the back as well

Haha I have been questioning that as well!

Did it this way to use the bolt holes included in the board, but might glass a structural piece in after I get it running. Cuz I’m not looking to snap the board in half on the first run!

The Motor is completed and is completely waterproof when static and submerged .5 meters for 8 hours

Here are some of the photos of the motor assembly process.

The Motor-to-Mast mount has been welded to the Mast. The design is definitely based off of the Hiorth Brothers Build. The propeller shaft is a 10mm x 80mm L shoulder bolt that i ordered from McMaster-Carr and cut the head off. That way it came with the M10 thread done and just required the pin hole to be drilled.


Nice build :slight_smile:

So you machined a custom aluminium tube for the motor, a custom cap for the gearbox, and then one last for the coupler ? The motor looks thinner than the machined gearbox head, how do you ensure heat dissipation witht the tube ?
Don’t you use any thrust bearing ? Don’t you get any friction from the coupler and his cap ?

Hi, nice build!

I also plan to mount a box like you in my board.
I bougt a prototyp (not carbon version) from a inflatable board.
I plan to shaping a own board next year and want easy change the engine, mast and batteriebox. So i decide the same way like you.
My question ist, i see your box is maximum strong, wich material you use, how thick it is. It seems to me that the box is very heavy?

Ma idea is, use down a 3m aluminium as top and bottom, the box with 2-3 cm wood, hope it is strong enough…

Yes there is a thrust bearing between the coupler and the gearbox mount. With the shaft of the gearbox preloaded prior to fixing the coupler to it as others have recommended on the forum. The tube is slightly larger. This was in hopes to buy a nominal sized tube and avoid machining. However this didn’t work and I had already finished the Gearbox coupler at this time so i plan on making a sleeve for the motor that will press on or machining a tube that has a small step for the motor area.

Mind you this has not been run in the water yet, but the box is completely aluminum and is 1/8" thick everywhere except for the O-Ring well. That had to be 1/4" thick in order to allow for the o-ring and thread depth. I guess it didn’t have to be but I wanted it to be. I made up a Excel calculator to define the ideal radius and side lengths of the O-ring groove. Because the radius at the corners cant exceed a certain point or the function of the O-Ring will affected.

After I verify everything works, runs, and functions as intended I’m going to design a new box and run 1 x 1 square aluminum extrusions down the center line of the board as many others have. This will allow for the box to be much thinner walled since it will bare minimum stress.

This is a nice piece of work really :slight_smile:

Any CAD or even Exploded PDF view file available ?

Yeah I can post everything when I get home from class

Would be really nice of you, thanks !

Nice project. Your Neil Pryde kitefoil CR:X front wing in the 500-600cm2 is small to learn efoil. If you are 80kg/160lbs, 800 is OK, 1000 to 1200cm2 is the easiest.

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Which foil would your recommend for learning? I’m planning on 90CM mast but not sure on front and back wing dimensions

Thanks! And that is good to know! I will have to look into other wings most likely since I have never foiled before.

I am very new to this and by no means qualify to give advice on the aspects of the foil. However @SoEFoil seems to know about the foil dimensions affect on stability. I am just a Mechanical Designer that got very interested in E-Foils when I first saw them!

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Have you got any experience surfing or any other sports like that? If you have, the foil size won’t matter too much. If you haven’t, then a bigger foil and slightly shorter mast (60-70cm range) can be a big help.

I live on a lake so during the summer I wake-surf and wake-board. In winter I snowboard

Also Jezza how does one post files to the forum?

Pics or 3d files?
Pics you just upload directly.
3d files need another sharing option

3d-files, looking to post the stls but see no option to do so