Hey all, I was looking around at the thruhulls and seacocks today and noticed that I've had the one in the picture open for the last year I've owned the boat. I closed it before taking the picture. It's is a drain for the sink in one direction, but in the other I haven't tracked it down yet. I believe it is likely the cockpit drain. I generally like to keep all thruhulls closed when I'm not using the boat, but if it rains, won't the cockpit stay flooded? Any idea why this would be below waterline? Should I be leaving it open? This is a 1985 30+