Bethwaite says that only the bows see laminar flow, the rest sees turbulent. With turbulent flow, surface smoothness is not so important, so just polish your bows. <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

I'd say this effect only has some importance when all other drag is very small, i.e. no waves, very little wind, low speed. In order to find out you have to do some towing experiments...