I did my carbon fiber mast repairs (6) pretty much the way CarlBohannon did: a mast section the same or close to the broken one. Be sure the cut section matches well when inserted inside the broken ends (some have flats or ridges to be shaved off). Difference- I inserted the U-shaped section in a polyethylene sleeve into one end of the broken mast then inserted 2 layers laid up over the open mast track side. Insertion of a cut and sealed motorcycle innertube attached to a stick allowes its inflation at 5 psi that makes a lovely oval shaped section to be pulled out when hard.

This completed oval section is sanded, checked for proper fit and length (accounting for about 6 inches of shattered bits). Externally sanded mast ends then are fitted for a 6 foot U-shaped wooden external trough to ensure straightness. Assemble everything first to be sure it all fits. Then epoxy plus some cab-o-sil thickener is buttered on each side of all contacting parts and the section is tapped into place in one end, pinning with a nail at the proper depth. The second half is then inserted until the correct length is obtained. Insert a section of angle aluminum into the exposed sail track, all then is wrapped with polyethylene and bungeed into the trough. ((No inflation tube up to the middle of the mast is necessary)).

Resulting repair: comes out absolutely straight but now needs reconstruction of the track- which does not need to be dramatically strong, just the correct width and smooth inside. ALso wrapping the depressed area with CF cloth to fill- probably mostly cosmetic but makes it look pretty good. None of these 6 have broken again at that repair over 2-5 years hard use, and appear to work well. Original mast bend restoration? Perhaps wishful thinking. But this made a strong, very light-weight repair.