Battery-Operated Travel Clock. Most cruise ship staterooms do not have a clock, you’re on vacation time. However, if you like to have an idea if it is morning or night – or would like to take a quick nap before dinner and don’t want to sleep through the night – then a small travel alarm clock is a good idea instead of having to keep your phone out and charged. One that is battery-operated is best as the amount of outlets in the cabin is minimal.