Thanks for the kind comments!
Is this completely covered wheel a trick for not having to build it or is it more real than suspected, due to protect it from gunfire in wartimes?
In period illustrations, you see a lot of wheels that are covered almost to the surface of the water. Until now, I never asked myself why they built it that way… I guess protection from gunfire was the main reason, the notion 'timberclads' was at first an ironic pun on 'ironclads', but those boats were quite sturdy.

This is the Tyler, together with her sister boat the Lexington she was involved in numerous fights, even supporting the Union troops in the Battle of Shilo. Also, in the later years of the war, Union steamboats were constantly threatened by snipers and hidden batteries, so additional protection for the paddle wheels makes sense.