Were the 18-inch guns truly designed around HMS Furious?
Short answerProbably not; they may have originated in a larger bombardment design and then been adapted for Furious.
NotesThe damage HMS Furious might suffer from firing both 18-inch guns raises doubt that the weapons originated with that ship. They may have been adapted to Furious from a somewhat larger bombardment or monitor concept. That hypothesis would help explain awkward features in the gun's development and installation history. This remains an interpretation rather than a settled design fact, so the qualification is central to the answer.