Beyond providing everything you need for a vacation, a cruise ship also provides transportation to a destination. Indeed, the demands of a cruise ship are extraordinary and so is the fuel consumption. Of the many fascinating questions cruise ships inspire, the most common is how much fuel they use.

Cruise Ship Fuel Usage

Size is key to fuel consumption and efficiency. A smaller ship will use less fuel than a large ship to travel the same distance. Both size and the average speed a cruise ship travels impact how much fuel it uses. On average, a large cruise ship can use up to 250 tons of fuel per day, which is around 80,000 gallons. Cruise1st.co.uk claims a normal cruise ship can use around 140 to 150 tons of fuel each day, consuming 30 to 50 gallons per mile travelled.

Similar to a car, traveling at higher speeds means an increase in aerodynamic drag, which directly impacts fuel use. Given that most cruise ships travel at 21 to 24 knots, this isn't often an issue.

In general, a large cruise ship up to 1,100 feet in length can carry as much as two million gallons of fuel on board. For comparison, a private motor yacht between 40 and 60 feet only carries 200 to 1,200 gallons, while something massive like the Exxon Valdez carries up to 55 million gallons.

The Guardian reported that the Harmony, owned by Royal Caribbean, has two four-story high, 16-cylinder Wärtsilä engines. At full power, they would burn around 1,377 gallons of fuel per hour, or about 66,000 gallons a day of high-polluting diesel fuel. It's important to note that Harmony of the Seas was the biggest cruise ship in the world until the new Symphony of the Seas took to the water in 2017.

Queen Mary 2

In the case of the Queen Mary 2, the ship is huge at 1,132 feet long and a weight of 151,400 tons. This storied passenger liner is built for speed and is capable of a cruising speed of 29 knots and a top speed of 32.5 knots. Compare this to most cruise ships and you can see that the QM2 is a water rocket. It travels at a brisk clip that requires more fuel. According to Chavdar Chanev of CruiseMapper.com, the QM2 averages six tons of marine fuel per hour.

Norwegian Spirit

At a petite 878 feet long and 75,500 tons, this ship is much more fuel efficient. When sailing, the Spirit chugs along at an average speed of 24 knots and burns approximately 1,100 gallons per hour. Thus, with a fuel capacity of over 350,000 gallons, it can conceivably remain at sea for 12 days without refueling.

Freedom of the Seas

Freedom class ships are all 1,112 feet long with an average speed of 21.6 knots. They are rumored to have a standard fuel consumption of 28,000 gallons of fuel per hour, which seems much higher than other similar ships. Their propulsion systems are state-of-the-art, providing a 10 to 15 percent fuel savings overall.

Size Matters

When considering how much fuel it takes to move one these massive vessels, it depends on the size and speed. Liners like the QM2 will need far more fuel than a smaller ship. The concept is similar to land vehicles. Naturally, a small economy car will run longer on less gasoline than a big utility truck. Though cruise ships continue to get bigger, there's always hope for better fuel efficiency.