Ludwig Kort (1888 - 1958 [1]) was a German fluid dynamicist known for developing the ducted propeller, or Kort nozzle. In an attempt to reduce canal erosion, Kort discovered that directing the wake of a propeller through a short, stationary nozzle also increased thrust.[2] He submitted a U.S. patent for this technique, which was awarded in 1936.[3] His research showed that the performance of ducted propellers heavily depended on the cross-section and thickness of the duct.[4]