Considerations on the application of podded drive on dredgers

Following recent developments of podded drive, IHC HOLLAND NV Dredgers (IHC) started in September 2001 a feasibility study of the application of this type of propulsion on hopper dredgers. Being convinced that clear conclusions can only be made via direct comparison, it was decided to study this new concept in conjunction with two existing concepts, the open-shaft and twin-gondola concepts. In this paper three concepts for driving the propellers and the pumps are first compared with regard to their implications for general arrangement and payload. Next the hydrodynamic performance of the three huil shape variants is evaluated by CFD analyses and model tests. Although the investigations have not been finished yet, the conclusion seems justified that in spite of a higher payload, the less favourable hydrodynamic performance in shallow water and the high costs make the podded drive concept not (yet) competitive with the twin-gondola design.