Originally Posted by LuceBianchi
The navy, however, is. You don't need to use fuel to stay at sea (you're likely to never get back to land if you run out, actually), nor do you need to use fuel to stay in space (excepting unstable orbits).
The Navy makes water, lights (and cools) the ship, cooks food for the crew. All use power (fuel)
A ship without power is uncontrolable (no headway for the rudders to work on).