Josef Ludvík František Ressel (in Czech) or Joseph Ludwig Franz Ressel (in German) or Josip Ressel (in Slovenian and Croatian) (June 29, 1793- October 9, 1857) was a Bohemian forest warden and the inventor of the ship's propeller.

Ressel was born in Chrudim, Bohemia, and worked as a forest engineer in Motovun , Istria (modern-day Croatia). He worked in Kostanjevica on the Krka river (modern-day Slovenia) where he tested his ship propellers for the first time. He relocated to Trieste (modern-day Italy) where his tests were successful. He was awarded the propeller patent in 1827. He modified a small steam-powered boat "Civeta" by 1829 and test-drove it in the Trieste harbor at six knots before the steam conduits exploded. Because of this misfortune, the police banned further testing.

In 1836, the Englishman Francis Petit Smith tested a screw propeller similar to Ressel's. The first cross-Atlantic journey of a ship powered by a screw-propeller was in 1839, with Ressel's screw improved by the Swedish engineer John Ericsson. The propeller screw design stabilized in the 1880s.

Among other Ressel's inventions are pneumatic post and ball and cylinder bearings. He was granted numerous patents during his life.

External links

• Short biography
• History of propeller inventions