The first steamboat, tested in 1807, was heralded as "the wonder of the age". The technology was developed and refined until a powerful steam engine, mounted on the light frame construction of a shallow hull, drove a side or stern wheel vessel. This became the pioneer form of river transportation in many parts of the world.
Steamboats convert water into steam in the boiler and it travels through pipes to the engine where the heat is converted into mechanical energy. A closed cylinder contains a large piston which moves back and forth depending on changes in pressure on each side of it. A crank and connecting rod (or pitman) attached to the paddlewheel converts the reciprocal motion of the piston into rotary motion to power the paddlewheel.
Paddlewheelers had little room in the hull for mechanical systems so almost everything was mounted on the deck. The boilers and cylinders were placed in a horizontal position to accommodate the space. The machinery and firewood on a large boat took up enough space that another deck was needed to accommodate the crew and passengers.
The boat was navigated from the wheelhouse where the pilot could see to negotiate shallows and snags.