"How do cruise ships float?" answered by a cruise ship captain
The largest cruise ships weigh hundreds of thousands of tons, yet they float effortlessly on the water.
For example, Icon of the Seas, the world's largest cruise ship, measures over 245,000 gross registered tons (GRT). While compared to Icon ships like Vision of the Seas are tiny, they're still large compared to other vessels, coming in at around 78,340 GRT.
As much as we'd like to believe that magic keeps these engineering marvels above the water, there's actually a scientific explanation as to how cruise ships float.