I have followed this forum for quite some time. Now is the time to ask my first question :) I'm currently working on a story in which a future, civilian luxury submarine is used to research some lifeforms in a water world. I am aware that current submarines would sink if turned upside down, but I'm curious is a future submarine with some science-fiction technology would be able to navigate in a freer mode, with greater flexibility to turn, go almost vertical and so forth.
EDIT: Thank you for your replays and sorry for the ambiguity. I will try to elaborate a more specific question. The submarine is trying to contact a suspected "intelligent" undersea species which uses movement as a way of communication. In trying to imitate their movements, the submarine should have to perform complicated movements such as those described: upside down, vertical, so forth. So, it doesn't matter if it's impractical or if it causes some minor damage in interior equipment: it's a matter of necessity (and, in the context of the story, rather urgent). The "general" submarine appearance is based on current luxury designs such as these: Phoenix 1000 I'm mostly interested in what kind of flotability technology would allow it, if there is such or its planned.