Steamships propulsion

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.

Sternwheelers, steamships propelled by a big paddle wheel positioned at the stern
This paddle wheel could be raise a little if the ship entered the shallow water. Sternwheeler has a control system that differs from other ships. On screw propelled steamships, the rudder is behind the propeller. A sternwheeler has its very large rudder ahead of the paddle wheel. This makes these steamships more manoeuvrable in astern than ahead goingt. Later sternwheelers have also been built with the rudder aft of the paddle wheel.

Some people claim that the American Ship Savannah was the first steamship to cross the Atlantic Ocean in 1819. The Steamship Savannah was on of the sailing ships fitted with a steam boiler, a steam-engine and a pair of side-wheels. During her twenty-nine days voyage they used the steam-engine less than four days. I don't consider that a steamship voyage. After that voyage the engine was removed and the steamship Savanna continued her days as a sailing ship. The Steamship Curaçao, a Dutch mail steamship crossed the Atlantic Ocean several times, mostly under steam power, in 1826-28. That I call steamship voyages.

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.