M_Boats: Sink drain thru-hull

I have noticed lots of discussion about checking/replacing the cockpit drain thru-hull because of possible corrosion. What about the sink drain thru-hull, on older M17s so equipped? I'm guessing this has not been a problem because it is slightly above the waterline and is therefore not constantly wet. Anyone have any issues with theirs? -- Henry https://picasaweb.google.com/heinzir