The Aqua can reach a lazy top speed of 17 knots (20 mph, 31 km/h), and it carries enough fuel to cruise at 10-12 knots for some 3,750 nautical miles, which would get you from New York to Barcelona without filling up. As for where you're going to find 56 tons of liquid hydrogen, well, that's your problem, and if you've got the money to buy 360-ft hydrogen superyachts, well, you're a resourceful sort, you'll figure it out. here