The man with all the gold braid is "
Captain, sir".
The man with slightly less gold braid is (when the
Captain, Sir speaks to him) "First Officer", or if familiar, "First".
The boy in the
Captain's Wife's seat is "Second officer", "Second" if familiar or "Boy" if he's good looking and the captain is that way inclined.
Please remember that one does not "tell"
Captain, Sir anything but the First Officer may, if very senior, "humbly submit" a question or a suggestion.
The bloke looking at all the dials sitting sideways is "Engines" and the fellow down the back is "Tail Gunner", although one may find the modern Admiralty frowning upon the term
