Have you ever looked up at a massive cruise ship and wondered how those things manage to stay afloat? I know we do a lot here at the Seattle office, and there are always a couple of cruise ships in the harbor here. During the summer there are constant cruises going up to Alaska and Hawaii. In the colder parts of the year, we’ve always got cruises to the Caribbean, Mexico, and other South Pacific destinations. Given that the cruise industry continues to grow, and lots of metal is involved, we thought we’d take a look.

Did you know?

Cruises are actually one of the older forms of modern popular tourism. The first cruise company was founded in 1822, the Peninsular & Oriental Steam Navigation Company. A British company specializing in trips to Spain, Portugal, and Egypt, they are still around! These days they go by P&O Cruises, but they are still the oldest cruise liner company in the world.

cruise ship

What do they make cruise ships out of?

The modern megaships were first built in the 1980s. Given the huge size of modern cruise ships, the most important word in their design is “weight.” When you consider that some of these ships are up to 500′ feet tall from keel to the top of the superstructure, it’s extremely important to keep weight down. This is both metaphorical and literal.

To keep the ships upright, all of the heaviest parts of the ship, such as the engines, powerplants, fuel tanks, water tanks, and ballast, are stored in the bottom 20% of the ship. Typically below the waterline, this keeps the center of gravity low and helps keep the ship stable. The remaining 80% of the standard cruise ship is made for passenger use, and is as open and light as possible.

As you look further up a cruise ship, you’ll notice that it gets lighter and more open, and this is to reduce weight. The one exception is the pool. Despite being very heavy, the view from the top of the ship is the best, so swimming pools always go on top.

The materials are also carefully selected and depend on where you are in the vessel. Near the upper levels of the ship, aluminum and high-strength steels are the most popular choices. These offer the best strength-to-weight ratios available. Newer ships have also begun to experiment with fiber-reinforced plastics and carbon fiber. Those are new though and remain fairly rare. As you get closer further down, you see more hot-rolled steels. Strength and heavy weight are important attributes here, so designers use denser materials there.

Like giant floating metal LEGO bricks

Most modern cruise ships are designed over about 12 months then build in 12-18 months. Given how big they are, this speed seems really surprising. This is because of how they are built.

The hull of the ship is built first, as it is the most complex and strong portion. It is designed almost like a big metal tube with a spiderweb of supports and watertight rooms in it. This is important, because the ocean puts a lot of stress on ships. Tubes are some of the most mechanically strong shapes in the world. But cutting holes in the tube, like you need for doors, weakens it. So the locations of doors are very carefully planned and then the structural web helps support it more.

Once the hull is finished, the superstructure is mounted on top. However, the spaces in the superstructure for all of the cabins and entertainment are left open. The cabins and everything else is assembled off the ship in self-contained boxes like a car. Once these flat pack rooms are built, they are slotted into the superstructure and affixed like a giant LEGO brick being plugged in.

Look inside the ship and these rooms, you see lots of facades. All those beautiful marble and wooden surfaces? They’re really thin sheets of stone or synthetic wood on light, strong, metal frames. Ceramics and stainless steels are also very popular, because those are strong but relatively inexpensive and non-flammable. That’s another rule of ship design, nothing flammable allowed.

Did you know?

Many of the newest cruise ships don’t use conventional propellers and rudders. Instead, they use what are called Azimuth thrusters. Essentially, they are smaller rotating pods with propellers on them that hang off the bottom of the ship. It allows for greater maneuverability and even for the ship to move sideways.

Who builds cruise ships?

Surprisingly, almost every single cruise ship on the ocean was built by one of four companies: STX Europe, Fincantieri, Meyer Werft, or Mitsubishi Heavy Industries.

No cruise lines operate their own shipyards due to the staggering cost and immense facilities needed to build these floating cities.

STX Europe AS

The newest of the four companies, STX Europe has six shipyards in France, Norway, Romania, Brazil, and Vietnam. Their shipyard Chantiers de l’Atlantique, in Saint-Nazaire, France, is one of the largest in the entire world, and it is where they build their cruise ships. The famous Queen Mary 2 was built here as well.

Fincantieri S.p.A.

The largest company of the four listed here, Fincantieri is actually the fourth largest shipbuilder in the world and the largest in Europe. Headquartered in Trieste, Italy, Fincantieri has 22 shipyards in Italy, Norway, Romania, the USA, Brazil, France, and Vietnam. Interestingly, as of 2017 they own 50% of the Chantiers de l’Atlantique shipyard along with STX Europe. At time of this writing, Fincantieri is in negotiations with the French government to purchase a majority stake in STX Europe.

cruise ships

Meyer Werft GmbH & Co. KG

Based in Papenburg, Germany, Meyer Werft is the oldest of the companies. Founded in 1795, they have remained a family-run business the entire time. Their main shipyard sits at the site of their original shipyard in Papenburg along the river Ems. They also own two other shipyards, Neptun Werft in Rostock, Germany, and Meyer Turku in Turku, Finland. Meyer Turku, which used to be part of STX Europe, also builds cruise ships, whereas Neptun Werft does not.

While not entirely relevant to ship construction, this is far too interesting to not mention: The Papenburg shipyard is the only cruise liner shipyard that is not on the ocean. The challenges around this were shown in 2014 when they launched Royal Caribbean’s Quantum of the Seas. They had to move the massive ship from the shipyard to the ocean, a full 20 miles away. And the river Ems isn’t that large.

It took them 12 hours to creep the ship down the river. The task was so stressful that they used six captains who worked in pairs for 90 minute shifts. At certain points, the Quantum only had 18″ of clearance from the keel to the riverbed, and about 20″ of clearance from the side of the ship to the riverbank. They dredged the river and even removed a bridge temporarily to make room. The fit was so tight that they had to wait for a day where there was no wind and there was no moon. The slight tidal impact from the moon might have made the ship run aground.

The best part? They didn’t get paid for the ship until it was delivered, so if it had run aground, they would’ve been out all of that money.

Mitsubishi Heavy Industries, Ltd.

Shipbuilding is just one aspect of Mitsubishi Heavy Industries. They are also involved in electronics, aerospace, automotive, construction, air conditioning, desalination, and defense, to name just a few things. MHI is also one of the older companies on the list. They were founded in 1884 when they bought the Nagasaki Shipyards, which remains their main yard. Their two other shipyards are at Kobe and Shimonoseki. During WWII, MHI also infamously built the two Yamato-class battleships, the largest battleships ever made. The first of the ships, the IJN Musashi, was so large that when it slid off the drydock into the water, it created a 4′ tall wave that flooded the entire neighborhood around the harbor and capsized many smaller boats. Both the IJN Musashi and her sister ship the IJN Yamato were constructed in the Nagasaki shipyards.

cruise ships

Nagasaki harbor

Did you know?

Many cruise ships are designed to fit in the “Panamax” category, which is the largest size that a ship can be and still go through the Panama Canal. This designation was created in 1914 when the Panama Canal was opened. In 2016, a third, larger, set of locks were opened, making Panamax larger. Current Panamax dimensions are 1201′ (366m ) long, 161′ (49m) wide.

Anchors aweigh!

Many modern cruise ships house as many as 2,000 crew who make sure the ship runs. Many of these workers are also Merchant Mariners who run and operate the fleets of cargo ships that move most of the world’s goods. We wrote a post about the US Merchant Marine in honor of National Maritime Day. Check it out and see what keeps the world running! We also have another post about what sorts of metals are used in the marine industry and why.

Do you have any good pictures or stories about how cruise ships are made? Are you somebody who has worked on a cruise liner and has some relevant stories? If so, let us know! And if you’re heading off on some cruise yourself soon, keep and eye out for the stuff we talked about today. Bon voyage!