Winterizing/isolating heads for in water winter prep

[1jparker]

We will be living aboard for the winter in New England, and want to winterize two of our four heads (1979 58'). Looking for suggestions, warnings with regard to doing this. We have heat throughout the boat, and are plugged in at a marina.
Thanks.

[aquacraig@shaw.ca]

IMHO there is nothing to winterize. You could shut-off supply to forward head and pump dry but 2 aft heads feed the same holding tank and probably are fed off the same thru hull. I use our boat all year in the PNW and with a bit of heat left on never shut anything down. I would me more concerned about fresh water pressurized lines to forward areas and in engine room. Cover vents and make sure they stay a bit warm or let a tap drip to keep flow.