I re-did one years ago. The epoxy wasn't so great a job and the cut was skew so we managed to pull it loose. I would think a gentle heat on the alum would turn the epoxy loose without screwing up the fibreglass. If you wrap a choker strap around each of the two halves with a "come-a-long" to the next convenient tree or post, you can get a good pull on it. Watch out, the plastic sail tracks love to break.
Cutting the "composite" would not be class legal, by the way,(would improve performance, unless you are a very light crew).