Read reviews for the 303 AeroSpace Protectant by 3M as submitted by your fellow paddlers. All of the reviews are created and written by paddlers like you, so be sure to submit your own review and be part of the community!
Be careful when loading your kayak after polishing it because the 303 will make it quite slippery to handle. I don't use it on the hull for that reason, only on the deck.
It is a UV protectant that doesn't leach out the plasticizers. Since it contains no silicones and is water based, not petroleum or alcohol based, it's a safer for the environment. But most of all, it works. It will protect your Royalex hull or the gel coat on your fiberglass or Kevlar hull.
Spray/Wipe it on and you can even just leave it to dry, though I use a sponge. It will protect your investment better than any other product I know of. BMW no longer recommends Armor All because it can leach the plasticizers. 303 won't. It can be a bit difficult to find, so try a local Marine store or order on line.