The worst thing about these ships (and boats in general) is that they all pose a huge threat to cetaceans (whales, dolphins and porpoises).
Cetaceans are all at great risk of getting hit by these ships, and certain species, like sperm whales, that spend more time at the surface, as well as newborns, that also spend more time at the surface to breathe, are put at an even higher risk.
Plus boats (and all other watercraft) make a tremendous amount of noise to sound-sensitive cetaceans. To them, it's like having a rocket engine right next to you at all times.
Gross tonnage is measure of total internal volume of ship. It doesn't tell anything about the weight of the ship. For that the term "displacement" ( how many tons of water ship displaces ) is used. Kindly stop spreading wrong information.
Most of the big container ships were manufactured in South Korea. Wow, it is amazing.