I am thinking about building an e-foil board, trying to get my head around the construction of the mast attachment / battery box area. I have build 10-15 foil boards for surf, sup, kite, wing. The way I learned to do the foil installation is to fill from deck bottom to top with high density foam, so that there is a connection between top and bottom, effectively making an I-beam … so the internal foam is resistant to compression and spreading the load. Without that, the tracks can compress into board, then gain leverage, and then pull out. Or you can potentially push mast right through the board. Seeking lighter construction, people replace some of HD foam by making pillars/columns that connection mast tracks to deck.
For e-foils, all the builds I am seeing on here don’t seem to worry so much about these potential failures. Main construction method seems to be to embed two stringers of wood or aluminum in foam extending beyond the box, then inserts into the stringer that are screwed into. But the stringers are not embedded in HD foam, even directly below the box, which seems to present compression potential.
As well, if the battery box is just glassed in at its edges, that seems to present potential for the whole box to be popped through the board with weight of rider pressing down against mast top. I am guessing that tying this into the stringers is needed to spread the load across the board?
I haven’t seen any threads about board failures…so I am assuming these are working out.
If you have any tips or suggestions for such builds, I’d love to hear them. Also, any board failures you’ve experienced that we can learn from?