Gigantic floating city design could become the world's largest boat
https://edition.cnn.com/travel/article/pangeos-terayacht-turtle/index.html
When it comes to gigantic ship where people live for a long time without calling at a port, it must be difficult to think about how to procure a lot of fresh water.
To solve the issue, the ship will need a device to purify water and desalinate sea water. I don't know if there is such a device on the ship.
