The electrics and motor are working nicely. I designed for 14 knots and measured 13.6. I’m still having trouble getting it to foil. Taking the straps off helped a lot. It looks like you need to kick it up but quickly shifting your weight back and then moving it forward again. It seems like one side of the wing is stalling and throwing me off the side. I’ll probably try a faster propeller next time.
Tons of fun to ride around on. Time to start working on the waterproof remote control.
Couldn’t the thing that trow you off be the wires running more on one side of the mast that the other.
On my first try i had the running like yours and it wasn’t very stable, for my second try, the wires were running entirely in printed part like the one in the picture below.
the outside shape is based on the mast shape.
It helped a lot to get less erratic reactions when trying to fly 
Wow, I didn’t consider that. But that could totally be the reason it is so erratic. Time to start printing or drilling holes in my mast. Thanks Mat!
It worked quite well in my case, but going through the mast is still a better option …
now that i know my system is powerful enough (and that i have a new mast for kitefoiling), next step is mast drilling and building a dedicated board (my case almost fell off during last test 
)
What are your plans for building a dedicated board? That is next on my list too. Everyone seems to be chopping up old wind surfers.
i’ll make it from scratch.
for now i have a rough 3d design:
6 feet long, 27 inch wide, 4.7 thick.
main design parameter is the volume, i’m aiming at 100+ liter (i’m70kg)
i want it floating while standing on it.
Right now it’s exactly 114 liter, so i might make it shorter.
Very simple shape, flat bottom on the back 2/3. flat top, very round rails.
Some nose rocker , but not very pronounced.
Mast will be almost completely at the back (attached most likely with threads, not tracks.)
Detachable mast for sure, with 4 bolts plate (liquid force spacing).
Battery and electronic bays isolated from each other.
extra space in both for autonomy expansion and electronics improvement.
Hand shaped out of polystyrene block.
Most likely a balsa wood layer on top and bottom between polystyrene and glass.
2 stringers (wood or carbon) bringing the load from the mast all along the board. stringers will act as the sides of the battery and electronic bay.
the hesitations are on:
I would recommend using a lot of round hatches and making the board completely hollow.
Hollow would give a lot of space… but how would you manufacture it?
and you’d also loose the “I-beam” effect of the foam that let you use thin fiberglass skins on top and bottom…
Three options I have been thinking about:
Stitch and Glue method. Google it if you don´t know it. This can be done without a CNC. Everything would get covered with carbon fibre. And then two halves joined together. Very labour and CAD intensive to make all the wood parts and internal structure.
Hand laminating or vacuum infusing 2 moulds. Making the mould is also very labour intensive. I could cut it on my CNC out of wood and then seal the fibres with gelcoat. 3 layers of carbon, then honycombe or similar and then 3 more layers of carbon.
You would make the hull and the deck separately, the deck overlaps onto the hull. To join them you insert the hull into the deck and the joint is filled with thickened epoxy as a filler. This would probably require a good amount of hand sanding the joint. Probably the lightest method.
Hey Mat,
Thanks for the details. I was also thinking of hand shaping out of a foam core. Possibly with a wood or a core-cell deck to stand on.
I haven’t thought too much about how to do the waterproof enclosures, but that part seems like it will be difficult. I might just end up with 2 pelican cases embedded in the deck. Maybe there is some OTS boat hatch product we can glue in.
https://www.nuovarade.com/product.php?productId=5718&categoryId=109
I have 2 Chogori Large Series IP67 connectors I may use to make the mast detachable.
I disagree with trying to make a hollow board. I have never seen a hollow surfboard. Huge structural and manufacturing cost to not having a core.
I’d use 2 or 3 of those connectors. I don’t recall if that rating is per pin, I think it is.
http://www.chogoriusa.com/large.pdf
They have different ratings 20A and 50A per contact.
I use a similar one rated for 35A per 4mm contact, tested myself with 80A permanent D-current.
Mine is suitable for 15 mm cable diameter, leads are 6mm^2 which corresponds to AWG10 in effect.
Cable and plug need some cooling by air at 80A, i use to wet them from time to time, if they get warm at all.
Also a 20A type with smaller contact diameter used to work without problems.
Next time I’ll follow this suggestion. 12 bolts to hold phenolic hatch are annoying!
I had to build a mold of the size of my battery housing and do the box, glue the box in, brass inserts for the screws etc.
I could have molded the box and attached it on a flat plane (carbon or whatever), drill the round hathc hole and glue into the foam blank prepared. Then you just laminate, that ain’t a hollow surf, it’s just a box. (Aviso made a line of hollow carbon surfboard 10 or more years ago… cool idea, expensives, no luck!)
And I will make a single box with sections, mast plug and that’s it
The beerWolf EFoil is now working and foiling reliably!
I bought a new 30inch mast and ran the wires and water cooling cable through it. @Mat you were right, the external wires were making too much drag. It is surprisingly easy to ride now that those are tucked away.
I am so happy that this is finally working. Now time to improve it! Waterproof remote, maybe a new board…
Awesome result, must be a good feeling starting to fly easily!
I got my waterproof remote controller working nicely.
It is based on a Grayhill 67A IP67 Joystick, a Teensy 3.2 and an nRF24L01+ breakout from Sparkfun.
All the electronics are potted with Smooth-ON PMC 780 Urethane rubber. Will post the design files on Github.
I’ve had about 8 rides in the last week. So far so good and much nicer than an E-skate remote in a ziplock bag.
I’ve added the design files and code for my waterproof remote controller setup here:
