Steamships propulsion

Paddle steamers, steamships with a paddle wheel on each side of the hull

Most paddle steamer had the wheels mounted on the same shaft and was driven by one common steam engine. The paddle wheels efficiency was very dependent on the steamship's draught, if they got too deep their efficiency was reduced. Even the ships rolling reduced the paddle wheels efficiency.

Stern-wheelers, steamships with one big paddle wheel by the stern

This paddle wheel could be raise a little if the ship entered the shallow water. Stern-wheeler has a control system that differs from other ships. The stern-wheelers have a steering system that is very different from other ships. On screw propelled steamships, the rudder is behind the propeller. A stern-wheeler has its very large rudder ahead of the paddle-wheel. This makes these steamships more manoeuvrable in astern than ahead goingt.Later stern-wheelers have also been built with the rudder aft of the paddle-wheel.

Screw-propelled steamships

In the end of 1850 the screw propelled steamships become recognized as superior to paddle-wheelers and after that the steamships began to supersede the sailing ships.
Steamships with screw propeller has a number of advantages and these steamships are better in rough sea since the screw is continually submerged.

Navy steamships

Navy steamships was originally propelled in the same way as the merchant marine steamships, but son they become provided with water tube boilers with higher steam-pressure and nowadays they are equipped with nuclear reactors for steam generation. Especially large navy steamships like aircraft carrier.