I'll share my thoughts on hull penetrations. First, my rule is basic, if it ain't used, close it. I've seen a lot of boats riding way too deep in the water over the years because owners had too much faith in what was behind the valve to keep the water out. Stuff fails when you least expect it. Stuff also happens when you least anticipate it. Some of this may come from my experience with/on submarines over the years. I've noticed that most hull penetrations can be somewhat easily reached on Ranger Tug (haven't crawled over every model yet), but it is one of the things I look at. I suppose I have an eye for the functional, whereas my wife will check out the wood work and fabrics (which are nice BTW). I also run my co-pilot (wife) through the most important parts of having a boat in the water (including hull valve locations. So, to sum it up, if it's in the water and not used, close it. If it's on the hard, keep them open, especially is subjected to freezing in the winter. Thanks for letting me opine on the subject.