Originally Posted by T.G

Bottled water that doesn't read "Minerals added for taste" or "Natural spring water" (ie: Evian, etc) would be the best bet, or hit up one of the medics for a bottle of "sterile water". You don't need much, I keep a 500ct cabinet humidor, plus a couple of coolers and a few small desktops and I don't think that I even use a gallon of water per year. Just get one bottle and only use it for the humidor, it should last awhile.

In a pinch, generally speaking because I'm not familiar with the specific engineering plant on your ship... assuming no contamination from the potable storage tanks or piping, the evap and/or RO water that you make aboard the ship should be ok, so long as they haven't taken on shore water recently.