My Prindle 15 went over on the beach at a local lake during a short lived, but violent wind and rain storm. No sail damage, but it bent the mast.
I spoke with the Prindle factor and based on their recommendations I straightened my bent P-15 mast by placing it on two solid objects, placed a piece of carpet on the area of the bend, and slowly and increasingly pressed down on the bend with my small tractor loader bucket. It eventually straightened out.
The factory suggested I consider installing Prindle 18 spreaders. They of course offered to sell me a new set, and also suggested I search for a used P-18 set. You might also consider spreaders from a P-18.
dan