thanks to everyone i finnally had a good look at the fin and noticed i hadn't sanded the filler coat after doing a carbon laminate
after fileing the leading edge with a file and sanding with the foam sanding pads problem solved
has anyone used these foam pads ,if not get them,you can dry sand without scratching,( its like being wet sanding), they dont clog like paper,and wash out under the tap and you can use them as wet and dry sanding
last winter i made a board and use'd these pads to sand the paint job, and was amazed that i didnt need water and today i wet them out to clean them and sanded wet, and was totally blow'n away
as we all know if you buy a new board this season , next season the bottom will need to be lightly sanded as well as your fins , my advice is atleast try them