Originally Posted by CLucas
Unless I'm missing something, I think the concerns you raise are more applicable to those who use the same thru-hull for sink drain and head intake.
Perhaps I should emphasize that the head intake/sink drain combo thruhull seacock is normally CLOSED at all times...except when the head is being pumped or the sink is being drained directly out.
In fact, all thru-hulls except the seawater engine intake and the two cockpit drains are closed at all times...except when a sink needs draining.
My goal in life is to reduce open holes in boats and to reroute all vent lines to the top of the cabin, insofar as this is practical. The common way of doing things makes me nuts.