ABSTRACT
Formulas to determine scour depth development caused by propeller induced jets strongly depend on empirical parameters. An earlier review of existing data revealed important gaps which have to be filled before improved equations can be derived. For example information for short load-periods are missing. This study is aiming to fill this gap and to compare the results with data of manoeuvring experiments. The effect of two propulsion units typical for inland vessels was investigated in laboratory experiments with a moving vessel. Scour depth development for two underkeel clearances was measured as a function of the number of transits over a sand bed and a fine gravel bed, respectively. The propulsion unit influenced the shape of the longitudinal scour profile. The underkeel clearance determined the effect of propulsion unit and bed material on scour depth. Comparison of transit and manoeuvring experiments revealed overestimation of scour depth by the latter.
