Kaplan Propeller:

The Kaplan propeller is designed especially for hard working Trawlers, Pushers, Dredgers and Tugs in which a nozzle is located to give greater thrust then open propellers. The large tip chord lengths of this propeller create higher thrust than conventional propellers. These propellers are best for fuel economy & excellent for fishing boats & Tug boats up to 14 knots speeds. Typically Kaplan Propellers with Nozzles derive 25-30% greater thrust for Trawlers and Dredgers, while harbor tugs can easily deliver 30-40% more thrust versus open or free propellers.