Resistance and Economic Speed of Ships and Tows in Inland Waterways

The resistance of commercial vessels in inland waterways is an essential and widely investigated problem. Depending on vessel and channel shape and size, many empirical equations were developed in the past to determine the resistance of vessels. In order to obtain an accurate relationship to predict the total resistance of inland vessels for variable channel and vessel dimensions, numerous model resistance tests with motor ships, push tows, and barge convoys were evaluated. If the speed of the vessel is limited to a defined economic speed, which is usually not exceeded in inland waterways, it is shown that the resistance from model tests of both ships and tows can be determined well by a resistance equation, which is based on a formula derived by van de Kaa for canals. A satisfactory agreement of the calculation results can be demonstrated for motor ships with measurements in field tests. It turns out that the adopted resistance equation of van de Kaa provides good results for inland vessels in a wide range of inland waterway dimensions.