This is picture of whats happening on the rails on my SUP Board . Any idea what caused it ? Does it need repair? It is a fanatic fly 11'6 approx 3yrs old Not left in sun stored in garage .
Polish ..a deep car polish ...maybe a light fine cut with a buffer ..first .thats how I get all my scratches out .and dulling .but very light cut ,meguires.product are the best .avoid the cheap brands .they scratch . the meguires yellow wax is great .and hides a lot of sins . i polish every month .keeps the dirt of too.
Could also be a friction (against the bag ?) if you keep your board on the side in the car/van. But most probably paddle marks, although I never saw them as straight and regular.