Oooh... That is a fine lot of nerdy goodness. I was able to scare up some images searching for "watt engine boiler"- a good set is at:
http://www.egr.msu.edu/~lira/supp/steam/wattengine.htm
And an earlier Newcomen engine at:
http://technology.niagarac.on.ca/people/mcsele/newcomen.htm
I was mainly interested in the brickwork, since there was some speculation that the Charlotte Dundas had a brick stack. Not really possible-see what happens to brickwork in an earthquake- but my best guess is that the idea came from viewing her derelict carcass and there was some kind of brick structure on the deck, maybe a brick smokebox at the base of the stack. The boiler was definitely set in brick as in land-based practice. The question is whether it was fully below deck, on deck or somewhere in between. There are references showing all three, and there were at least two Charlotte Dundases... Since I am working with an existing solid hull, this version will have the boiler mainly below deck.