Yeesh, replies seem a little harsh ... as I read it, these are "foil drive issues" as in "issues the OP is having with using his foil drive". His posts didn't imply it's a defect or bad product, said straight up he probably hit stuff. Seems to me the reply may be: 1) you can't use the FD plastic props in your situation, they are not designed to withstand that abuse; or 2) consider one of the metal prop options, but with the risk that instead of breaking prop you may break another more valuable part up the chain.
I am attempting DIY e-assisted options, with 3-d printed parts. So far in our crew, I'm the only one regularly breaking parts.

Mostly due to clearly identified stupid reasons, but also some mystery breakage: one session I broke my prop blades, there was quite a bit of wood in the water, none near me, but my suspicion is some was below the surface....and I think even a small bit could snap it, possibly even kelp/seaweed, but definitely if there's any loose bits (leash, battery box tie down, slack in motor wire, etc). In looking at metal props, I am a little worried about the potential for damaging other bits....may be cheaper to replace prop blades as the planned weak link.