The Biggest Cruise Ship on Earth Is 250,000 Tons. That Is Not What It Weighs

Icon of the Seas is listed at 248,663 gross tons, and that is not what it weighs. In this video, drawn step by step: how tonnage began in medieval England as a count of wine casks called tuns (252 gallons, about 2,240 pounds: the long ton), how a formula from length and width stood in for it for two hundred years, how George Moorsom replaced the guess with measured space (100 cubic feet to the ton), and how the 1969 convention turned it into enclosed volume times a factor: a number with no unit that sets a ship's fees. Then the real weight: a ship weighs what the water it pushes aside weighs. For the biggest cruise ship that is, by our rough estimate, about half the famous number. And the biggest tanker ever built had almost the same tonnage and more than five times the weight. All drawings are schematic and not to scale. Our own arithmetic and estimates, labelled on screen: 248,663 GT = about 780,000 cubic metres of enclosed space (from the convention's formula); 365 x 48.5 x 9.25 m = about 164,000 cubic metres as a box; x about 0.7 (our assumption for the hull's fullness) x 1.025 t/m3 = about 117,000 tonnes. The operator publishes no displacement that we could find. Watch next: How the Biggest Oil Tanker Ever Built Stopped (It Took 9 km). If this was worth your time, a like and a subscription help the channel. And tell us in the comments: which part of a ship should we take apart next? Chapters 0:00 250,000 tons 0:52 The plan 1:04 1. The barrel 2:20 2. The box of air 3:56 3. The formula 5:40 4. The real weight 7:36 So what is 250,000 tons 7:52 Three takeaways Sources International Maritime Organization, International Convention on Tonnage Measurement of Ships, 1969: https://www.imo.org/en/About/Conventi... Wikipedia, Gross tonnage (formula of the convention): https://en.wikipedia.org/wiki/Gross_t... Wikipedia, Builder's Old Measurement (the tun, the tax of 1303, the old formula): https://en.wikipedia.org/wiki/Builder... Wikipedia, Icon of the Seas (figures from the DNV vessel register): https://en.wikipedia.org/wiki/Icon_of... Wikipedia, Seawise Giant (gross tonnage and displacement): https://en.wikipedia.org/wiki/Seawise... All animations are original; diagrams are simplified and not to scale.