Ant-man said..
I've clipped a 2m hammerhead, just missed a big turtle and cut a big eel in half but the worst thing I've hit foiling is a 1 metre length of partially submerged PVC pipe (full of water), not good. Lake Mac NSW.
Oof
After one of the hurricanes here I went out and was thinking about launching but I saw a huge steel dumpster in the water and a partially submerged, detached dock. Decided it wasn't worth it to be the first person to find another hidden object the hard way.