NavList:

David McN asked "so what was noon?"

I would say that in the nineteenth century noon was approximately equal to the time of LAN. The ship's time was set to 12 hours when observation showed maximum altitude of the Sun. Eight bells were struck when the Sun started to descend. Later on, early twentieth century, the practice was to adjust ship's time in the morning with the aim to get ship's time to show 12 hours at LAN. Then the noon sight observation was made at 12 o'clock exactly, not caring whether the altitude was increasing or decreasing. A typical example of this practise is an entry in the log book of the four masted barque Abraham Rydberg, in March 1930: "time aboard according to 72°30' W." To facilitate computing daily average speed (for steam and motor ships), tables of co-logs for every minute of time between 23 hours and 25 hours length of day can be found in e.g. Burton's nautical tables. Even later, starting between say 1925 and 1940, zone time was getting used, and noon then corresponds to 12 hours zone time.