Welcome to the forum Tom, my first two cats were Stingrays a great boat! The rear beam would have started straight, the holes in the rear beam could have been to lighten it or might be access holes to nuts inside the beam can you see the bolts for the traveller track through the holes? You really need a new main beam and new strap for the dolphin striker there is no short cut your up for a length of pipe for the front and rear beam, Nacra will have the parts or specs for everything you need. The bad news is you are up for a few dollars but the good news is you'll have a great boat for not much