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Old 12-17-2014, 08:00 PM   #25
DavidM
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City: Litchfield, Ct
Join Date: Aug 2012
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Let's talk about seacocks and whether you should leave them open or closed after winterization. Both ball valve seacocks and tapered plug seacocks have a cavity that if left full of sea water could freeze and damage the valve.

So if the boat is on the hard- absolutely, positively, no question- leave all seacocks open so the cavity will drain and it won't freeze.

But if the boat is kept in the water, then it is a bit more problematical. You probably want to keep your seacocks closed, just as a good precaution against hoses popping off or whatever that might sink your boat if they are left open.

If you are in moderate climates where the water doesn't freeze around your boat or you have a bubbler that keeps it ice free, then you can probably close he seacock and not worry about the cavity freezing.

But if you are in harsher climates, say north of the Chesapeake, the water can freeze deeply- 6" or more, and even a bubbler won't keep it ice free in an extended power outage.

In this case, most ball and plug valves have a little 1/8" NPT plug that can be removed when the valve is closed to drain the cavity. Whether you leave the plug off or not during the winter is another question. Tapered plug valves particularly can leak and let sea water refill the cavity. So I would leave the plug off in that case. Ball valves with Teflon seats seal very well and if you know that your valve is in good shape and seals tight I would put the plug back in. But leaving it off until spring is safest.

David
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