Walt I tried a clear water base spar finish from varathane this spring on two kayaks that stay car topped on my daughters car all summer. The finish did not hold up as well as oil base. The test had one issue she got caught in a hail storm that did pretty good damage to the car areas that were not protected by the kayaks. I really don't know if it was the hail or sun that did the damage. The sides of the kayaks that were not exposed to sun and hail still look good.