There are still a few steam-powered riverboats running today, although they do have increasing problems. One can see how they
function in the above picture. Best of all, is to start with the two boilers on the left and on the right, the water in the piping is heated through coal firing and the exhaust gas escapes through high funnels. Mounted in the center, between the two boilers, is the actual engine, horizontal pistons drive a transverse mounted crankshaft. The crankshaft-ends protrude from the hull at about midships and carry enormous paddle-wheels.
One can only be amazed by the 'fuel consumption' of steamships. For example, if they work hard upstream the whole day, as tugboats, they can easily consume up to 1,5 tons of coking coal. 05/10