Regarding typical Reynoldsnumbers of sailing, shark skin or riblets would be useful for a beach cat, if they are available, applicable (can be glued on 2-axes-curved surface easily, does not get contaminated, or could be replaced easily, if contaminated) and would be offered at a realistic price.
Have you ever seen, that a shark is surounded by small fishes which de-contaminate his skin? I wish there would be some fishes which do it with my boat.

Cheers,

Klaus