Nope, not designed for that type of load and especially not designed for horizontal load. That arch is thin fiberglass (to be light weight), I believe and I bet it is only thru-bolted with small 1/4" bolts. It is very likely the strain will rip the bolts through the fiberglass. That arch was only designed to take the load of a few antennas and possibly a radar array. A skier or a wake boarder can generate 500 - 1000lbs of force (especially a wake boarder). That would rip the arch off the boat.
An arch designed to handle that would have to be custom made and through bolted with very large backing plates.