Publication Detail


Jan Holtrop, Patrick Hooijmans
5 pp.

Several past ITTC committees dealing with powering performance and propulsors have advocated the load-variation test as a valuable addition to the more usual speed-variation test. This loadvariation test is even essential in complex propulsors and it can certainly not be dispensed with when hybrid propulsion concepts are studied by model experiments. At MARIN the load-variation test for one test speed has become a standard addition to every propulsion experiment and, indeed, the information about the effects of the varying load is analysed to enhance consistency and accuracy.

At MARIN it was investigated whether the usual test procedure could be simplified and the loadvariation test can be fully dispensed with by carrying out propulsion experiments in a quasi-steady manner. In the quasi-steady method described here, a gradual variation of the rotative speed of the propeller(s) is imposed, while the forward speed of the ship model is kept constant. Thus, the load of the propellers continuously changes during the measurement run.

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