The paddlewheelers on the U.S. inland rivers have a very broad and flat hull. This gives the boat a great buoyancy. So even the very big boats have a very low drought. This was a most important characteristic of the boats, because they had to go far up the rivers even in the summer months, when there were only few water in the rivers (at this time there had been no locks to regulare the water, of course).
The second, also very important advantage of the flat hull was the fact, that there was usually no damage, when a boat hits a sand bank. This happens very often, because the rivers, especially the Mississippi was not a single day the same as a day or a week before. Even in 1995 this happend to the brand new American Queen (Delta Queen Steamboat Co.) on her inaugurational cruise. It took some days to bring her back to deeper water, but the hull was not damaged at all.
One big problem in building a steamboat, especially when building a wooden construction, was the heavy weight of the boilers, the engine and the paddle wheel. Only massive bracing with a difficult-to-build hog chain system all over the boat prevented the boat from braking in two or more parts. Later, when hulls were built from steel, this problem was almost solved .