It is difficult to find precise mpg figures for smaller cruise ships, but it’s possible to get a rough estimate based on engine outputs. Cruise ships in the Voyager class are about 311 meters in length, but have a tonnage of “just” 138,000 Tons (compare that to the 6000+ passenger Oasis of the Seas, which comes in with 225,282 gross Tons). The Voyager class boats use diesel engines, which combined have a total output of 75,600 kW.
Assuming an efficiency of about 30% means the boat is burning roughly 1.84 gallons of fuel per second, or 6640 gallons per hour. Since the ship’s cruising speed is 23.7 knots, or 27.3 mph, the cruise ship’s fuel efficiency is roughly 0.004 mpg. Since the ship carries 3114 passengers, its gas mileage is 12.79 mpg/passenger, or 17.65 mpg/person including crew. This isn’t too different from the much larger Oasis of the Seas, one of the largest vessels in service.
See this article from Bright Hub Engineeering for more information.
THIS IS FOR 3000+ PASSENGER SHIP
* At 6640 gal/hr and 10 hrs/day = 66400 gal/day
* 7 day cruise = 464,800 gallons
* 3000 passengers implies 155 gal/person for 7-day cruise
* 155 gal x 22.4 lb CO2/gal = 3470.5 lb CO2
* 3470.5 x 0.015 = $52.06 OFFSET COST