Hi, I've been fiddling around with one of my seacocks. I've never fiddled
with them before. It's the one that the sink drains through. Anyhow it's
old and could use replacing, but I can't really afford that. So I went to
replace the plastic tube that the sink drains down through into the seacock
through the hull because it was old and nasty, and when I took the tube off
the seacock water stared gushing up through it. I put the tube back on and
the water filled the tube about 4-5 inches and then it stopped. So it seems
that 4-5 inches of water is nessary to keep the through-hull from letting
water in. Is this normal? Because if so it means that the little metal
bands holding the drain tubes on to the seacocks are the only thing
preventing the boat from sinking, and that seems a little scary.

Thoughts?