uncapped liquor...
Leaving the caps off won't hurt distilled spirits. Most bars replace the caps with pour spouts once the bottle is opened. The main reason for recapping liquor is to keep the fruit flies and other pests out. They like brandy, whiskey and some cordials. They crawl in the bottles looking for sugar and the alcohol kills them immediately. When you get to the boat, shine a flashlight through the back side of the bottles to check for the little dudes. If you find any, you can strain the booze through a coffee filter or cloth napkin... or you can throw the booze out if you want even though it's still good.Regarding wine: oxygen is wine's enemy. Wine is not distilled, it contains organics that react to oxygen so you want to minimize the exposure. A nearly full, opened bottle of wine with very little oxygen will last much longer than one that is half empty because there's more oxygen in the bottle. So, the rule is: once the wine bottle is open... drink it within a couple of days. That said, I've had opened bottles of wine last weeks. Trust your senses if you're not sure. There are systems available to remove the air from opened wine bottles that work pretty well.Fortified wines, such as port and sherry should be okay, but a taste test will tell you whether there's been any change to it.