It will certainly get hotter but if they did any damage I don't think anyone would sell them,
We do black boat covers all the time at work and I have never heard of any damage from them.
Welcome to I Boats. You ask a question. What Damage are you talking about? You never said. Is it mold? The only damage I have ever heard of from any cover is where the islets wore a spot of what was being covered. That's not the fault of the cover but the person doing the covering not to protect the item being covered from the Islets.
