Outdoor Model Tests for the Evaluation of the Manoeuvrability of an „Inland Waterways Container Ship“
As part of an industrial project for the American Patriot Holdings LLC (APH) dealing with a new concept of an inland waterways container carrier (designed by NaviForm Consulting & Research), outdoor manoeuvring tests were conducted to complement the standard resistance and propulsion tests.
The manoeuvring tests were performed in a sheltered little bay of the Berlin part of the river Havel in the city of Spandau. The approximately 9 m long ship model (scale: 20) was manufactured at SVA Potsdam and, in accordance to NaviForm specifications, equipped with modelled superstructures and stylized containers. The ship was propelled by 4 VSPs, of which 2 were used solely for propulsion and the others mainly for manoeuvring purposes. The drives were provided by Voith Turbo GmbH & Co. KG. In the manoeuvring tests straight line, turning on the dime, turning circle and dock moving sidewise tests were conducted.
The tests were performed for a single draught. The thrust distribution scheme for the 4 drives which was identified as the best during previously conducted towing tank tests was also used in the outdoor tests. For full scale speeds of 8 kn and 12 kn straight line and turning circle manoeuvres were demonstrated.
The model tests were documented with video recordings. Beside a stationary camera a quadrocopter drone was used that provided recordings from different views of the manoeuvring behaviour of the ship.
The results showed that the targeted speed of 12 kn in straight line test could easily be achieved with the optimized thrust distribution scheme for the 4 VSPs. A turning circle with a diameter of less than 7 ship lengths can be achieved for a velocity of 8 kn and a thrust direction of 10°. At 12 kn the diameter of the turning circle spans about 7 ship lengths.
Due to the utilization of a purpose built wing system at the ship’s bow a considerably reduced wave system could be observed even at a speed of 12 kn.
In general a very good manoeuvring performance could be demonstrated for this inland waterways container carrier.
Author: Dr.-Ing. Matthias Fröhlich, Schiffbau-Versuchsanstalt Potsdam GmbH