We have had a few customers come in looking for a product we no longer carry: the old McNett 303 that some people used on the decks (and hulls?) of older kayaks.
This products usefulness on our new fabrics is debatable, we no longer use it, but acknowledge that some would like to. I actually think it could be very useful in protecting boats in extremely prolonged solar exposure, such as:
-sailboat deck stored kayaks
-rental boats or tour fleets
It can be found at the MEC in Canada and the REI in the U.S.A.