Without a 100% disassembly, extremely thorough deep cleaning and rinsing, and anti-corrosion coating- one day the rust will return. WE saw the same situation on TAC back in the early 2000's. A TAC member's Brewster in Louisiana or Texas (can't remember which member lived where anymore) was submerged and subsequently sold to another TAC'er. Literally a complete teardown and rinsing. Those little body crevasses that you can't even see in, or get your smallest brush in, hold dried salt water. I hope they succeed, but I would never attempt it myself.