Black vertical streaks, some darker than others.
After cleaning when it does rain they come back right away, but like I said this never happened on my old boats and the rain water in NE is from only the finest springs in Maine smile
I compounded the crap out of my 20 and waxed it and it looked great sailing in in the Steeplechase and Tybee, but I sold it the day after so I don't know how it looks now.