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.
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