No seacock in galley sink drain.

[PaulRainbow]

Not if you heeled the other way.

My galley sink plug hole is about 3 feet above the waterline, two feet off the centre line.

 

[Jaguar 25]

My galley sink plug hole is about 3 feet above the waterline, two feet off the centre line.

This is getting a bit silly now but if the boat heeled significantly over on the sink side, the through hull fitting would always be below the water line.

 

[PaulRainbow]

This is getting a bit silly now but if the boat heeled significantly over on the sink side, the through hull fitting would always be below the water line.

Of course it would, but the plug hole won't be below the water or the through hull.

My through hull is below the waterline anyway.