Hello,
when I fist saw the picture, I was also astonished about the similarity with paddlesteamers on African or Asian rivers.
May be, it is possible, to get some drawings or plans when connect the server of the site?
A more European example of sternwheeler is found on the german site about "Dampfer Elsa" on river Fulda in Hessen.
The stern wheel was driven by chains through steamengine until the beginning 60s, with diesel engine until mid 70s!
regards
Thomas