I have an advert from National Geographic 1918 which appears to be a full page stating...The Waltham Chronometer times the war ships of Uncle Sam and Britain. etc etc I know many dont concider this to be a Chronometer but that seems to me to be a split decision... My questions for these are..Were all of these used during first world war on US Navy ships and not just torpedoe boats ie as master timekeeper? The up graded ones used in second world war were these only used on small coastal ships? Was this watch developed by Waltham for US shipping during first world war? Ive seen ads suggesting this to be the case. One thing I do know ..I have one only genuine key for the inner box..All of my last 5 Waltham chronometers have been locked with this key..no its not a skeleton key. I wonder if Waltham only used the same lock and key for every unit. I find this lovely piece a thing to admire, with a beautifull wooden box made by true craftsmen, have a look at how the brass pieces are attatched. They are a lovely talking point situated on top of coffee table and it has a function that only needs winding weekly.