Hi Chris,
I don't have the streak problem, but maybe squirting around with a hose will show you where it's coming from. The toe rails and stantions should be tight to the deck and not trap dirt. There are voids however inside the winches and the stantions/bases. I drilled some (additional) limber holes in the winch bases last time I removed them. Maybe alittle teflon wax on the hull will help?
