First I would like to thank all the great people on this forum whose story’s I’ve been following for a long time now. I was always close to start my own project. Anyway I stopped my plans a few times being convinced it makes no sense here in South Germany (black forest) with all the restrictions.
A little bit about myself:
I got into kiting 2016 - kitesurfing became The Thing for two weeks a year on holiday at north sea mostly. All efforts to kite at home ended in disappointment
I think 2022 I started with pump foiling on the nearest lake which really became the thing closest to “real” surfing locally.
Last year I learned wing foiling which is also quite nice. Sadly also not the dream conditions here at home.
After getting good enough with the pumping I started imagining catching the waves at north sea must be really fun. So I got finally caught by the foil assist idea and quickly ordered some essentials:
Chinese 6384 Motor is already disassembled and waiting for some resin at work
I have an appletree surf foil board 47l available I would like to use. With 76kg there should be no big issue getting started.
Regarding the enclosure I’m not sure yet. I started playing a little in CAD. Also I have ordered a Bopla A124 Box. To sum it up I have the following options:
FD gen 2 inspired like @Bzhwindtalker. Advantage would be direct cooling by the mast base and not damaging my board. Biggest disadvantage I see is the remote connection and a neat, waterproof battery connection. I would definitely opt for a SLS printed/ milled housing once my design is good.
Inset Bopla aluminium box from the top like @hangloose. But I’m not sure how good signal strength would be. I guess I’d need to make a plastic antenna stripe in the aluminium case - right? Also there would be the need to make room for the cable and connector coming from the motor. I’m not sure how to make the place for the box solid and looking good in an existing board?
The antenna signal with the Bopla is no problem! I have no problems with my 2nd build where I installed the Bopla from below with Maytech V3 Remote. However, my RideEngine board is made of GFK. Since you want to install the Bopla from above, I don’t see any problems with the signal at all.
Good luck with your build! Foiling is what reconnected me to watersports, living 3 hours from the nearest sea.
Regarding the under board, having an antenna extension or longer antenna completely eliminate the signal issue. Handling the antenna is kind of a hassle, but with some adhesive Velcro should solve this.
Being able to change board is great, to go for different disciplines or use case with the same hardware.
First of all, thank you so much @hangloose for sharing some more details aside from this thread!
@Bzhwindtalker I see the advantages of having a board-independent system. Also I played around in CAD with my own design of a waterproof under-mast battery. @Jordi is also doing a great job of the FD replica - by the way thank you for the help with my ESC (more on that in a second)
Anyway I think I will continue with the inset Bopla/ aluminium box approach. My main reason is having less seals to worry and minimum drag. Also a 12s3p battery which I want to use would be pretty thick (~70x75x280mm). Remote signal will be improved with some window design or an external antenna.
Let’s talk a little about my progress:
Motor half way prepared. It will get a 2k black top coat which I will also use to seal the stator stack (not potting).
Working on fixing my ESC. I found a little component missing after disassembly. Luckily @Jordi already helped me to find out what I’m searching for. Maybe someone else could confirm I’m missing a 1608 metric resistor code “60E” which translates to 4,12MOhm.
Enclosure. I already got a Bopla A124 (120x360x81mm). BUT I’d like to get it a little smaller and if possibly lighter. The length and width of the Bopla interferes with my strap plugs which I would like to keep. So I came up with my own design:
Outside dimensions are 110x315x81mm which saves 45mm in length and makes the Box fit right in between the strap plugs. A nice benefit is the weight saving of about 800g which already accounts for 12 of the 21700 cells.
To seal the Box I would use the same idea as Bopla probably with silicone:
Pricing would be around 260€ - not cheap but at least cheaper than my prop
Some off-topic might be interesting for pump-foilers. Im currently also redoing my pump board. It held up great for about 20-25 sessions of pumping. Just bare paulownia laminated to a hollowed core sealed with bionol boat varnish. 30mm thick in total - consisting of 2x5mm (perpendicular fibre) deck, 10mm core hollowed, 2x 5mm bottom (perpendicular fibre). Since I started using the Indiana Condor XL the forces became a little to high leaving dents on the bottom and slowly ripping the printed cones trough the deck. So now it will get a layer of glas to improve surface strength.
interested to know more about your pump board, where did you get the wood?
I was looking into airex for my next build, but it’s quite expensive and wood could look very nice for a GF only finish.
It was 140€ (220€ incl. shipping to Germany) for 20pcs 1000x150x5mm and 10pcs 1000x100x15mm which is enough to do two boards. Boards came planed - I only went over the edges before gluing them wit PU expanding wood glue.
Rocker is done by a simple 3D-printed wedge on a thick multiplex board, some beams an clamps for lamination - also using PU glue.
Currently I will only repair my first board since the wood is still great. It weights around 2,3kg without glass. at 35mm thickness overall strength is awesome I do not feel any flex when pumping. I cannot noticeably bend the rocker when standing on it with two people, one on each end, 200kg in total.
Since the “no dirty glass/ carbon” strategy did not work out I would probably reduce to 5mm deck/ bottom on 15mm core hollowed with one light layer of glass. The additional 5mm wood top and bottom on my current only where used to get in some cross fibers since planning without fiber glass reinforcement. Mounting points always glass ball filled through-holes - no track needed on a 84cm board.
Motor is done. I soaked the windings with some special clear insulating varnish made for coils. After drying I gave the rotor and stator a nice coat of 2k black in order to look nice and have some protection from abrasion. Also since I spent some money on the coating and varnish I got a second motor prepared right away.
Motor mount is done. First some prototypes printed in PLA and now I just received a nylon SLS version from JLC. The green spacer is cast from silicone.
Battery is done. I used some 3D-printed (also nylon from JLC) spacers and end caps. The battery should be semi-waterproof - at least thats my future plan maybe with some new end caps and better shrink wrap. For that reason I use a waterproof connector on the balancing side.
As you can see the Bopla A124 box is also done. I ground down the markings on the bottom side (around 1mm high) and painted top ant bottom both in black to better fit my carbon board. While doing the cutout on my board I noticed the M20 connector is really long and I’d have to do a cutout under the mast base. For that reason I changed to @hangloose solution of the cable gland. To get a good signal I already ordered some external Bluetooth antenna which will go through the deck and get clued to the box externally.
Board destruction phase started with making a big hole in the bottom. Of course taking a lot of safety precautions with the carbon dust (class H Vacuum, Mask etc.) First I cut the carbon layer with the rotary tool and afterwards removed the foam with router and hand tools. It seems that the box will protrude around 5mm from the hull.
Cost until now for the whole setup excluding the foil equipment (mast, base,…) and board I’m at roughly 1200€ with some extra money spent in replacement motor, connectors and other supplies. One should keep in mind I also had to buy the expensive Junsi charger and some tools. So it can be cheaper if you use parts already available and stay with FDM prints.
Maybe some interesting part prices:
JLCCNC Aluminum ESC cooling block: 32€ for two sets (used some coupon codes)
JLC3DP Nylon SLS battery spacer: 35€ for one set (also coupon codes)
JLC3DP Nylon SLS motor mount: 60€ for on set
Wasted around 130€ in wires, connectors I opted not to use and BEC (will be replaced by BEC pro)
