Supersized Ships

As a chilly wind blew in from the North Sea, hundreds of people gathered on a coast in the United Kingdom. It was March 2015, and they had come to see the arrival of a new ship.

This was no ordinary vessel. Pulling into port, it towered over the cheering crowd. It rose 22 stories high and stretched the length of four football fields. The ship, called the MSC Oscar, is one of the largest container ships in the world. 

Hundreds of people gathered on a coast in the United Kingdom. A chilly wind blew in from the North Sea. It was March 2015, and they had come to see the arrival of a new ship.

This was no typical boat. It towered over the cheering crowd as it pulled into port. It rose 22 stories high. And it stretched the length of four football fields. The ship is called the MSC Oscar. It’s one of the largest container ships in the world. 

The metal containers the ships carry are the size of semitrucks. They shuttle goods around the world—everything from clothes and computers to cars. The MSC Oscar can hold more than 19,000 containers. That’s enough space to fit 1 million washing machines!

Large ships can transport many products in a single trip. That means shipping companies are racing to supersize their fleets. But building big boats also comes with big challenges.

Ships like this one carry metal containers the size of semitrucks. They shuttle goods around the world. They carry everything from clothes and computers to cars. The MSC Oscar can hold more than 19,000 containers. That’s enough to fit 1 million washing machines!

Large ships can transport many products in a single trip. That means shipping companies are racing to supersize their fleets. But building big boats comes with big challenges.

Container ships are made from steel—a strong alloy of iron, carbon, and other materials. To construct another new mega-ship called the Maersk Triple-E, builders used more than 60,000 tons of steel. That’s enough to make eight Eiffel Towers! 

Steel for a ship’s hull comes to a shipyard in enormous sheets. Machines cut the sheets into shapes that fit together like puzzle pieces. Workers heat the steel to bend it. Next, giant cranes lift the segments and place them next to each other. A robot melts their edges together.

Once the hull is complete, the ship is ready to float. But launching this huge structure isn’t easy. “You can’t just pick it up and put it in the water,” says Paul Miller. He’s a ship designer at the U.S. Naval Academy in Annapolis, Maryland. 

Engineers have a clever solution to this problem. They assemble ships in large pits right next to the water. Doors keep most of the water out while a ship is built. When it’s done, the doors open. The ocean rushes in, lifting up the ship.

Container ships are made from steel. Steel is a strong alloy of iron, carbon, and other materials. Builders used more than 60,000 tons of steel to build another new mega-ship called the Maersk Triple-E. That’s enough steel to make eight Eiffel Towers! 

Steel for a ship’s hull comes to a shipyard in giant sheets. Machines cut the sheets into shapes. They fit together like puzzle pieces. Workers heat the steel to bend it. Next, giant cranes lift the pieces. They place them next to each other. A robot melts their edges together.

The ship is ready to float once the hull is done. But launching this huge structure isn’t easy. “You can’t just pick it up and put it in the water,” says Paul Miller. He’s a ship designer. He works at the U.S. Naval Academy in Annapolis, Maryland. 

Engineers have a clever solution to this problem. They build ships in large pits next to the water. Doors keep most of the water out while a ship is being built. The doors open when it’s done. The ocean rushes in and lifts up the ship.

The biggest container ships can carry almost 200,000 tons. How do they stay afloat? It has to do with density.

Density is the amount of mass an object has compared with its size. Denser objects pack more matter into less space. If an object is more dense than water, it sinks. Objects less dense than water float.

Ships float because their curved hull holds a lot of air, says Dave Gerr. He’s a boat-design expert at SUNY Maritime College in New York. Air is far less dense than water. That makes the overall density of the ship low enough to float—even though materials like steel are too dense to float on their own.

“If you took all the material in a ship and crushed it together so there’s no air, it would sink like a stone,” says Gerr.

The biggest container ships can carry almost 200,000 tons. How do they stay afloat? It has to do with density.

Density is the amount of mass an object has compared with its size. Denser objects pack more matter into less space. An object sinks if it’s denser than water. Objects less dense than water float.

Ships float because their curved hull holds a lot of air, says Dave Gerr. He’s a boat-design expert in New York. Materials like steel are too dense to float on their own. But air is far less dense than water. That makes the total density of a ship low enough to float. 

“If you took all the material in a ship and crushed it together so there’s no air, it would sink like a stone,” says Gerr.