There are lots of these around, running beautifully after a hundred years. Mine was born in 1903, serial #7243. It is visiting my favorite clockmaker/compass adjuster for lube and adjustments. He is generally very admiring of Chelsea clocks, but had this to say about it --
"The real annoying thing about this clock is that it was not equipped with a back door for observing the hammer. If it doesn't hit the gong properly a wild guess adjustment has to be made, return the movement to the case, and hope for the best. All other Chelsea ship's bell clocks I have worked on have a back door."
So I wonder when it was that somebody decided that the back door would make life easier? Who has one, when was it made, and does it have a back door?