while this looks very nice, I very much doubt the large circular engine room around the paddle wheels and the bulkheads around it, could you explain what exactly that space is?
other then that, nice work, and my only remark would be that the underwater hull could use some shading to represent it's actual shape
as it looks a bit flat right now.
EDIT: and I just noticed, something wonky is going on with the propeller, 2 of the 4 blades are more forward than the others.