If you're building a submarine, you don't have to call it a "future submarine" until it submerges; people understand that if you say "I'm currently building a submarine," it has yet to go under water, but the thing you're building is still a submarine. I think that's generally true of not-yet-built or not-yet-used things: it's understood that if it hasn't done the thing yet, you're describing what it's going to be/do.
