Good evening
Congratulations for your project
I am new on the forum and I embark on the adventure for the construction of an electric hydrofoil
I recovered the STL files and started 3D printing.
I have a question about the tightness of the motor cables that must go up in the foil
how did you do so that the water does not get inside?
Thank you in advance for your help.
Giloris
Welcome @giloris. There is water inside my mast and around the cables and I am not worried about that. The old LF masts were always filling up, bottom and top connections are not watertight. The critical cable seal is in the mast mount, the 3 holes where the cables go into the tube. I fill the cavity up with plenty of silicon there which I can also remove quickly if I need to do maintenance. I explored a pod-plug option too, posted here somewhere, and I have read several other ideas on how to seal cables. But I am ok with my silicon right now, simple and works. Lots to read up on if you are new 
Good luck with your build!
Thanks a lot for the clarifications.
The configuration you tried working well?
On my side I will try to embed in the surf the electric elements and then put a watertight hatch
Could you give me the dimensions of your surf?
What length did you put on the tube or the motor?
Have a good day
Giloris
Yes, It’s board size
Don’t have detailed measurements but it’s the one @RIDEHYDROFOILS offered here: Boards for eFoil - Foils & Boards - FOIL.zone. I am sure you will find more details online about this board. I like the size, works well for me.
thanks for these informations
I will continue my project and post the progress on the forum. could you tell me the length of the tube of 60mm where is the motor and the reducer?
Thank you and good day
Giloris
@pacificmeister I’m using the new Rocket Foil V2 from Liquid Force, which is 130 mm long. I tried adapting the CAD file for the clamp system and it looks like my foil is quite long as you can see on the image (I haven’t moved anything, just modified the sketch to my new dimensions). Will it make any problem like that?
@Fabien_n
Yes if you print it like you show in your picture, you wont be able to put the alloy tube to the mast mount. Because the mast destroy the mounting ring.
@pacificmeister
at the moment i am waiting for the coupler of the neugart. in the mean time i tried to put everything else together and there i recogniced that there is a problem with the ThustBearingMount.stl
The
Thrust Needle Roller Bearing 10x24x4 Thrust Bearings from your part list has 24mm outer diameter but the in the thustbearingmount.stl it has only 22,6 or i dont now the measurement in the file but i printed it and the neddle bearing didnt fit and so i measured it.
Also the diameter from the outer side of the thustbearingmount.stl didnt fit to the neugart.
Neugart has on this site 26mm and the 3d part has 24,6mm.
I am wrong or do the file have wrong measurements?
greets
OVER
Strange. Can you check the dimensions in he fusion model? Maybe something went wrong with the STL export.
I also have the rocket foil, just made the mount a tad longer on each side Foil mount I can post the file if you like
Thank you all for your help! Yes pacificmeister, I checked the dimensions and it really seems that the rocket foil is too long. So @Sourcecode yes it would be so nice if you could post this new file as I’m really bad in CAD! What are the exact dimensions of your foil? Liquid Force says 124 x 13.5 on their website but mine is 132 x 19 in reality.
@Fabien_n Yep is is 132mm. I think that measurement is for the 2016 foil maybe? I used 2 M6 130mm long stainless steel bolts to clamp them together i also have a water cooling intake on the mount but i removed it in this version of it
Rocket foil mount
Thank you so much! Yes I think that’s the 2016 on their website, mine is a 2018 I got from a friend that has kite shop. I will use a water cooling system as well, but haven’t yet figured out exactly where to make the hole for in on the mast. Did you do it on the back, the side or the front of the mast on yours?
@Fabien_n . No problem! i made a 6mm hole for a pipe going back up the mast to the ESC. The hole is on side of the mount where the cables come out of the mast. Im gonna use a self priming 12v/6v pump that can suck water from 3m and pump it 2m or so.
pacificmeister, apologies if you have answered this already, but 1) what soil section is your duct? 2) you are twisting the water with the struts that hold it steady - is this to counteract the twist you get in from the prop? It doesn’t appear so if your prop is a CW screw… how does this work? 3) what section are you using on the prop, have you seen cavitation to date? Thanks.
Hi Brent, i am not sure I understand all your questions. Regarding the angled duct struts, I took this idea from the @Hiorth duct. Worked well. Only thing is that it creates a CCW moment on the duct an I had it unscrew once while riding and it melted into the prop. That’s when I added the little set screws. Don’t know what the science is behind the angled struts. @Hiorth? Are you guys still doing that on your latest desing? I want to continue trying different duct shapes to see if I can reduce drag at highes speeds.
Hey pacificmeister,
Thanks for reply. I did see your thread problem - that sucks. But if you mirror the thread it’ll probably over tighten though, just to be ironic and difficult.
I don’t like ducts in theory, because they are lossy and eventually limit speed. Also, the chances of getting an accelerating duct like a Kort/Rice style nozzle right without CFD are pretty poor. Why don’t you try a pure 0012 with no angle of attack? The drag can be calculated quite easily. I think 0012 is about the lowest drag foil you’ll get.
The angled struts are interesting because at 0 m/s, they’ll do nada, but at higher speed they’ll turbulate and twist the water. The former is of no use since the Re of a fast blade isn’t a problem, but the twist could be opposite to the twist introduced by the prop giving lower wake turbulence/twist, perhaps an efficiency bonus. The water hitting the blade at the right angle for good ‘push’ essentially… ?
The main loss of energy and cause of inefficiency is pushing water. small props jet water backward. The shape of the wake you make is an expression of efficiency, and ordered directional wake means you’re doing it right.
The foil you are using in the duct is chunky and I’ve not seen it before. Curious to know what it is. I’ve tried naca4415 after reading a paper, but haven’t gotten too far.