What does KT really mean??

[Kagetora]

Well I would suppose they are using the same system that nuclear weapons use in which a kiloton is 1000 tons and a megaton is 1 million tons. I would point out that naval vessals on water aren't usually described by their actual weight but by the amount of water they displace which is not even close to being the same. They must displace much more water than they actually weigh in order to float.