The JIB® propeller (named after the triangular staysail that sets ahead of the foremast of a sailing vessel) is a propeller whereby each blade consists of two separate sections, reminiscent of a compound or tandem propeller, but here the sections and chord lengths of the two propellers are distinctly different.
Studies were done by the Technical University of Delft and open water tank tests were carried out by MARIN in Wageningen, showing that the JIB® propeller performs considerable better compared to an open propeller at highly loaded conditions and is rated as good. The propeller outperforms an open propeller at heavily loaded conditions by about as much as 14%.
The JIB® propeller is a good alternative to a nozzle. In particular for applications where nozzles cannot be applied or preferably are not used, like in shallow draft application on for instance ferries and workboats.