Might want to drill a small hole at each end of the tear to keep it from spreading. I wonder if you rough it up if you could lay fiberglass and epoxy over it to strengthen the area. Or maybe get some plastic from a bucket, 55 gallon drum etc and bolt or rivet it on over the crack. Possibly plastic weld the crack, but I think some plastic takes better to that than others.
Worst case you may want to call Clam. They may have a new sled you can buy. My brother took my old Fish Trap Guide after I wore holes in the tub. A year or so later got a replacement tub from Clam. This was the last couple years so the Guide was a pretty outdated model.