re: Stainless Steel Boat Hinges Rusting

The hinges mount flush with the deck so there's a shallow pocket they sit in in the fiberglass. When we wash the boat, this area can never be fully dried by hand. So the water sits and the hinge rusts a little and when the water evaporates, the rust residue is left on the fiberglass. You can see it along the edges.

Here's a pic of the hinge. Those tiny scratches cause the issue: