actually the guy felt bad and took off hundred bucks cause he wasted my time now i own it. it didn't take on any water, but one rudder does need some work. i am good enough with fiberglass to fix it myslef.
I need to know how much the mast is suppose to spin on this cat. is there a bracket to stop it from spinning too much?

I can't remember my prindle too well, but the mast won't rotate too much because the shrouds will stop it from going too far... unless your boat is really funky. On my nacra there isn't anything to stop the mast from spinning (it is mounted on a ball) except the shrouds and it all works out.

You should be able to achieve about 90 degrees of mast rotation when sailing downwind. If you are getting more than that, you definitely need to tighten the rigging (shrouds and/or forestay). Most catamarans have some sort of rotation limiter for use upwind to keep the mast rotated at about 45 degrees (pointing at the leeward shroud).