ships sundial marked capt. willis green

i found this solid bronze sundial in west mystic ct where the man said it had been in the yard for 60 years or so.... im hoping someone knows something about these things... im not even sure if ships have sundials on them... w mystic had tons of boats come throught there either built or repaired... a quick search of capt green says he came from st john so he could have been in mystic at one time or a boat of that name came through.. any help would be totally appreciated
6 lbs.. 12 in dia... cast bronze