just by looking at the very clean and straight crack, I'd wager there's a weak point in either the core or the layup on that line. Perhaps a butt joint in the core where two halves were glued together. Or some discontinuity that caused a stress riser in the laminate. But it's probably the board and ...

I know this isn't what you're asking, but is there any particular reason you need the carbon to be continuous across the edge? There's no real structural benefit.
I'd do the top and bottom with the fabric flat in the moulds and then trim and sand the edges once the moulds are removed.

If these are pinhole size, it's very difficult to get epoxy in there as the resin tends to seal the hole before the air can get out. I've had mixed success with a syringe and needle. Would it be possible to put the needle of an empty syringe in the hole, then fill the hole with epoxy (while the syr...

If these are pinhole size, it's very difficult to get epoxy in there as the resin tends to seal the hole before the air can get out. I've had mixed success with a syringe and needle. Alternatively you can try to thin your resin with acetone and see if that will be thin (non-viscous) enough to get in...

Mine is wakeskating with a 17m BRM C2 I owned a 17m C2 for years and I can't imagine how you could keep upwind on it with a wakeskate, it was hard enough with a surfboard. Props if you can make it work though. These days I ride an OR Flite 17m in 9-20 knots, I weigh 75 kg / 165 lbs. Dunno what woul...

It depends on what your version of fun looks like
Mine is wakeskating with a 17m BRM C2

Some more variations over here

https://e-surfer.com/en/

Very interesting. I assume you wanted to have this on both sides. But with a system to connect both rear lines inside the bar tube (like in the Kauper Bar, I have done in my DIY bars also) you could also have it only on one side and adjust both rear lines at the same time. - Tom Yeah, one on each s...

I prototyped a rear-line adjuster a while ago, that replaces the bar floats. Which means it would work with pretty much any bar. It would allow 20cm of trim on each rear line by turning the red adjuster nut. The black shuttle would connect to one line end and the other line end to the screw body. Th...