I assume that with steam paddlers both wheels can only go in the same direction and at the same speed as they are on the same shaft.
I have read somewhere that with at least one of the diesel electric paddlers on Lake Geneva that each paddle wheel is powered by a separate electric motor which might allow theoretically, if not practically, one wheel to go ahead and the other astern or some variation thereof.
I can't find the reference now but some good person here on SN might be able to confirm this (or alternatively hit me with spread of torpedoes).
