My general feeling is that if this were really practical, there's no way we'd be hearing about it. The technology, and its author, would be quietly vanishing into the Naval Research Laboratory.

I wonder what does happen in those situations, actually. If I, as a university academic, invented something that could make a submarine undetectable, I'd be willing to consider any cash offers to keep it secret that the US Navy might be willing to make. But how do I approach 'em?

I've never heard of this kind of thing happening... but then again, I wouldn't, would I?