My 2 cents....Our beloved watercraft deserves a decent home.  Lots of low buck canoe and kayak hoists with enough pullies to gain mechanical advantage, so that anyone can raise them against the ceiling of a garage.    Most hulls are only 15 inches or so deep.
They will be up and out of harms way and the UV rays will have a hard time finding them.  The PVC and other polymers will eventually give in to the UV and start to get brittle and chalk on the surface.