If you have your first cruise booked in the months ahead, you might be wondering just how fast your cruise ship will be travelling.
The speed of a ship is measured in knots (‘kn’), with one knot equal to one nautical mile per hour, which is approximately 1.151 miles.
The speed of your particular cruise ship will depend on the power output of the ship’s engine, and its size and weight. Ships that have been built for speed can travel as fast as 30 knots (around 34.5 miles) or more. Larger cruise ships will typically travel at a slower pace of around 21 – 24 knots (around 24 – 28 miles) although this is still pretty quick in terms of speed on the water.
A number of additional factors can influence the speed of your cruise ship, as follows:
- Route: Your ship will travel at a speed that is suitable and appropriate for the route that it is taking to your destination, which may vary.
- Fuel: Ships travelling at their top speed will use more fuel and your ship may therefore travel at a slower pace than its maximum speed to ensure that there is enough fuel for it to complete its voyage. Cruise ships use a huge amount of fuel, with the distance travelled per gallon measured in feet, rather than miles. 10 gallons of fuel will take the average cruise ship just a few hundred feet! Some ships have to refuel at ports along the way to your destination.
- Pace: Your ship will travel at a pace that is appropriate for your itinerary.
- Distance to shore: If your ship is close to a port, the Captain will sometimes reduce the speed. If it has reached the port ahead of schedule, the Captain may even decide anchor away from shore for some time.
- Open water: If the ship is in open water and the next destination is far off, it will usually sail at a higher speed.
- Points of interest: Your ship will slow its pace to allow you to appreciate and take photographs of areas of beauty.
- Hazards: In some areas, your ship will need to proceed with extra caution – such as in Alaska, where glaciers are a hazard.
- Weather: The Captain may adjust the speed of the ship to take account of the weather conditions, particularly if they are less favourable.
What keeps such a large ship afloat?
You might be wondering how such a gigantic vessel can possibly stay afloat, let alone achieve such impressive speeds. The answer to this is displacement. When people talk about how heavy a ship is, they tend to talk about displacement rather than weight. The cruise ship displaces the equivalent to its weight in water when it pushes down on the sea, which pushes up and keeps the ship floating. Weight, measured in gross tonnage, is still a relevant factor however, and a good indicator to would-be cruisers of the size of the ship.
Displacement is different to gross tonnage and not directly equivalent. For example, the Titanic had a gross tonnage of 46,329 GRT with a displacement of over 52,000 tons; in contrast, most contemporary cruise ships weigh about 100,000 – 110,000 GT but displace around 50,000 tons.
The Oasis cruise ships owned by Royal Caribbean International are in a class of their own. The Oasis of the Seas, finished in 2009, has a gross tonnage of 225,282 GT and displaces an impressive 100,000 tons, just shy of an American Nimitz-class aircraft carrier. Despite its colossal size, the ship can still achieve a speed of 22.6 knots, equivalent to 26 mph.
If you want to know more about how cruise ships work, take a look at this post.
Images sourced via Flickr Creative Commons. Credits: Don McCullough, stereotyp-0815