Devices improving the manoeuvrability characteristics of ships Part II ”Doerffer’s Rudder” – experience learnt from tests carried out on real ships

Abstract

An account of research activities on the devices improving the manoeuvring abilities carried out at the Gdansk University of Technology were presented in Part I of the paper. Experience from implementation of open rudders on real ships is presented in PartII. Open rudders were fitted on two full size ships: a 1000 BHP harbour tug and a 2500 BHP long line fishing vessel. Designs were made for four types of ships: motor sailing passenger ship “Gwarek” (2 x 1.032 BHP and 1800 m² sail area); arctic expedition sailing ship m/y “Polarex” (length 40,4 m, 1200 BHP); rescue vessel R-27 (two engines à 600 BHP with single propeller); harbour tug m/t “Atlas” (2500 BHP). None of these designs was implemented due to financial difficulties of the owners. Further model experiments with a self propelled model of a cargo liner m/s “Hollandia” exceeding 20 knots were carried out on the lake as well as with a model of a twin screw vessel.