"It’s not, that we know of," said Bigend, "but it’s sometimes at the center of a stack of much heavier containers. That’s a very secure position, as there’s ordinarily no way at all, at sea, to access a container in that position. The Hook, though, would allow you to do that. Plus you could have arrived from somewhere else, another ship say, with your container Hooked. Decent cruising range, reasonably fast."