[trit21]

I don't think I would come to that conclusion. I have read your post on boatdiesel as I have been a member there for years. The only sure way to determine if your stock Cummins exhaust 'riser' (not really risers since they point down) have been compromised to is to remove and inspect. Stock Cummins risers need to be inspected and replaced as they are steel and will rust internally allowing salt water to flow into the turbo. From some of the photos posted, it does look like the water line is close to the exhaust turbo outlet that it may allow splash back of salt water at times, not all the time but I can see where there could be an issue. My exhaust, 6bta 370hp 3500 Open, is not stock Cummins but made my Marine Exhaust in FL. It has a high riser and the raw water is on the downside approx. 20" away from the turbo exhaust outlet. If I was you, I would remove the turbo exhaust coupling and have a look, won't take that long and will tell you loads of information.