One of None
This may be unique to Odays since they have the exhaust in the center of the transom and at the water line when the boat is under way. My engine on the trip used about a half of quart of oil in what was about 6-10 hrs a day for nearly 10 days while on the Chesapeake. I don't think it's excessive oil use that causes the soot. I do think the exhaust gases get condensed and the soot makes a line across the transom at the water line. I don't see anyway to eliminate this problem other then to relocate the exhaust outlet higher as it is in other boats with transom exiting exhausts. what say the jury???