[There were some mounted artillery cannons on the ships as well, so Robin just assumes that's what he's talking about.]

No, they have the kinds on little wheels as well. If you're as big as that one who turned into a boat, you could probably carry one. Unless you're really weak for your size or something.

[Her interactions with Riptide have been limited. She never actually got his name.]

Well I don't know very much about the sorts of weapons the military use, but... Just don't expect the sorts of things that you might find on a ship like this one.