New Under Sol Update: The Largest Ship...

Shell Prelude FLNG

The Largest Ship Ever Built
24 December 2010

About 3 years ago, I told you about the largest ship ever built, the oil tanker Mont (the last of many names it had), which was built in 1979 and finally sold for scrap in 2010. This ship was over  450m (1,500 ft) long, and weighed 565k tons. The Mont dwarfed both the largest aircraft carrier, the USS George H.W. Bush (333m); and the largest cruise ship, the Allure of the Seas (362m). The USS GHWB was launched in 2009, and the AotS was launched in 2010. But now there is a new champion of hugeness, and it's not a military vessel, pleasure ship, or oil tanker.

Shell Oil Company needed a way to extract natural gas 200 miles off the coast of Australia. They could build something like an oil platform, but natural gas is very different than oil. Since it is a gas rather than a liquid, it is very difficult to transport long distances without pipes -- oil can be pumped directly into oil tankers and moved across the water, but natural gas takes up too much space for that to be a profitable means of transportation. On land, natural gas is piped in from the gas fields to huge facilities that cool it down until it becomes a liquid (-162° C/-260° F), which decreases the volume by 600 times. The liquid natural gas is then transported in trucks or trains that keep the cargo cooled.

To solve the off-shore problem, Shell designed a Floating Liquid Natural Gas (FLNG) processing plant. It reduced the footprint of a plant so all of the components can fit into a much smaller area -- in this case, a large ship. The ship motors under its own power to a spot right above the natural gas deposits. The gas is then brought directly into the plant, which uses sea water to cool the gas into a liquid, and then the liquid gas is off-loaded to transport vessels.

Shell is calling this ship the Prelude FLNG. Its hull has already been built and out of drydock. However, the ship will not sail into position until 2017, at a total cost of up to $12.6 billion. Yes, billion, with a "B." The size?

• The oil tanker Mont was about 457m long and weighed 565k tons.

• The Prelude is 488m (1,586 ft.) long and weighs 600k tons.

• The cruise ship Allure of the Seas is 61m wide and up to 20 stories tall.

• The Prelude is 74m (240 ft.) wide and its highest point is over 300 feet (30 stories).

• The aircraft carrier GWH Bush has a surface area of 4.5 acres.

• The Prelude has a surface area of over 7 acres -- which is more than five football (American or other) fields combined.

The Prelude is the prelude to whole class of similar FLNG ships that will ply the oceans. When I say "ply," I mean "stay in place for decades after 'sailing' to a designated spot." The Prelude, for instance, is scheduled to remain as stationary as an island for about 25 years. So, in 2042, this blog will be reporting that the Prelude has moved for the second time in its career.

If you wondered if the largest ship in the world would be taller than the Taj Mahal if the ship were to be carried to India and balanced on its stern, the above chart provides you with the answer.