For one thing, there should be a hyphen in stainless, as in stain-less (vs stain-more). It is a product of iron so some rust is inevitable, and some alloys do better than others. It will probably even rust to some degree in North Dakota, but will surely do so if the boat is used in salt water.
The best removal treatment for rust, if that is what it is, is a product containing Oxalic Acid. The one we have always used is simply Bar Keeper's Friend, a household cleanser, available at most supermarkets. If not that brand, look for others with Oxalic Acid. It dissolves iron oxide. For light rust, just moisten the area, apply the powder and "scrub" with a non-abrasive cloth or pad enough to distribute it. Let it sit a couple minutes and "scrub" it off. For heavy areas, make a paste of the cleanser with water, apply it heavily to the area, let it sit 15 minutes and wash it off. Repeat if necessary.
The other great thing about Bar Keeper's Friend is that "Made especially for boats!" doesn't appear anyplace on the label, so the price is right. As a bonus, you can use it to scrub your pots and pans in the kitchen/galley.