So 10,000 gal per mile say 3000 mi across the ocean so. About 30 million gallons to cross the Atlantic. Yea, I'd say it's a hoax.
One of the best things that ever happened to me was starting engineering before calculators and learning the slide rule. It forces you to do an approximation to get the range before the slide rule gives you the digits. Makes it easy to spot silly statistics etc.