I have it on one of my rigs. Around 110 jumps on that one. No corrosion so far. No water landings, but the hardware has been wet on many occasions from landing in wet fields and snow. It is always hung up immediately after getting wet though.
Keep a light coat of silicone lubricant on it. Salt water enviroments aren't the best locations to have black or standard cadium hardware, but you've probably figured that out yourself.
Hey, I have black hardware on one of my rigs - started getting surface rust soon after I got it. I used a mild metal cleaner and a rag rather than emery cloth, I would guess it's not the best idea to introduce surface scratches to a stressed metallic component. Cheers