IMHO it is not the tooling, it is not the polish. 304 stainless will rust in a salt water environment, regardless of polish. 316 stainless won't. The only way to prevent rust on 304 is to keep the salt water from coming in contact with the metal. This means coat it with wax, lacquer, or some other waterproof surface coating. Then the lines sliding over the winches will abrade the finish off! That means you can't use your winches again. OOPS!
At least the metal is not poisonous, like the pet food procucts, toys, etc we have been importing. When are Americans going to learn that cheap Chineese products are CHEAP! When you replace those winches, read the fine print. Metal parts used on salt water vessels should be made of 316 stainless. A chrome plated bronze winch is better, but a 316 stainless winch will be lower cost in the long run, but they aren't cheap!