I have used polyglow on my boat and the results were stunning. My hull
was already a very light cream color, but I did not notice any additional discoloration at all. Even if it were the case, if your considering polyglow in the first place your hull
is probably in a condition that a nice polished slightly yellowed color would still be preferable to a dusty, chalky white! The other option... painting the topsides. A $100.00 solution or $5000.00 solution.