As a US Navy navigator in the early to mid 1970's I was responsible for all my ship's timepieces. I can attest to the fact that during periodic Navy Yard overhauls all USN ships sent their clocks/chronometers off for servicing and it was not unusual for there to be irregularities in the accounting of said items. Some went missing and/or extra clocks were returned, it created a accountability nightmare for the ship's navigator. Outright theft was rare, usually missing/extra clocks simply vanished into a labyrinth of bureaucracy, sometimes to reappear in the civilian world. Since this clock and pre-War case do not date match it is possible that the original works were "surveyed" at some point in the late '30's early '40's but the case became notable after December 7, 1941 and was saved by someone astute, to eventually be reworked in 1971. By then though, almost all USN Chelsea clock cases were made of a impact resistant "Bakelite" type material, were larger and had white or black faces and very different works. This could be a special situation since the only brass face/case Chelseas I remember were a very few in senior officer's shipboard living quarters and they were never sent out during overhaul. Where was this case for 30 years and how, why and who, reworked it? If not done by a USN facility for a senior officer it would have been a very expensive proposition. Sorry this is long but this timepiece has a story to tell and is very interesting.