My grain of salt. Usually UV radiation damage is determined to have occurred when fabric has discoloured and become sticky to the touch. Since your boat is covered the stickyness may be caused by the powerful Starbrite cleaner you are using. The Starbrite containers don't show what chemicals are used in the cleaners but I would say they have to be pretty strong to do what they claim to do. You may find the formula by looking at the Material Safey Data Sheet that is prepared to U.S. OSHA, CMA, ANSI, Canadian WHMIS Standards and European Union Directives. There is also a possibility that the cleaner interacts with something else. Personally I use soap and water to clean my RIB and then apply 303 Aerospace Protectant. Following is a link to the chemical data:
http://www.westernmarine.com/msds/sta83416.pdf
