No comment on LL and warranty, but for repairing a cracked boat in a semi/permanent way duct tape will not work. You need to have some bitchethane (roof patch material) or vinyl mastic tape. Nothing else will seal the crack and be watertight. Both are available at hardware stores. Best move is to get a hot air gun heat up the cracked area in kayak, warm the bitchethane, slap on patch generously, and heat a little more. I have milked more runs down Vallecitco and other pretty clean runs with a patch.
"The future ain't what it used to be" - Yogi Berra
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