dirty line on transom from exhaust

[mikehmc]

the exhaust outlet goes underwater on our islander 30 at about four knots. we get a grey line at that waterline on transom. it does not just wipe off, need chemical to remove. we tried many coat wax
on transom hoping would brush off easier. we put an extension pipe on exhaust. still get dark line at waterline.

any ideas how to prevent ugly hard to remove line at transom waterline?

[delmarrey]

Let me know when you find out!


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[nimblemotors]

It can be fixed so it will never happen again by converting to electric propulsion.
Other than that, I don't know.