It takes 1 gallon of diesel 1 fuel for a cruise ship to trarel 6 inches how many gallons will it take for the cruise ship to travel 1 mile

The last cruise I went on had a cocktail party for returning guests, which the captain attended to participate in a question and answer conversation. One of the questions asked pertained to the amount of fuel a cruise ship uses. I can't remember everything that was said, but I do remember the captain saying one gallon of fuel moved the ship a mere 17 inches!! So I would imagine close to a thousand gallons of fuel would be needed to move the ship one mile..