My 26 had the rudder blade covered in many layers of antifouling, lumpy and several different colours. As I leave the rudder fully up on my mooring, where I ground occasionally, I removed all the gunk and sanded the blade smooth, making good the odd dents etc. I then applied 4 coats of 2 pack white gloss. It looks good and I can imagine thhat extra 1% of speed!
I also removed all the paint from ths stock and polished the aluminium, even with 30 years of wear and tear I think it looks better than chipped paint.