Danish/German ferry operator Scandlines has installed new propeller blades on its ferries serving the port of Rostock, thereby optimising the vessels for their current operating profile, and resulting in improved propeller efficiency and a saving in propulsion energy of some 11%.
In 2016, Scandlines introduced two new hybrid ferries on the Rostock-Gedser route. The ferries were specially designed for the route and for a speed of 20 knots with three engines in operation: two on the centre propeller and one for the hotel load and thrusters. As part of the company’s green agenda, the speed has been reduced to 16 knots and therefore only one engine is needed on the centre propeller. The propulsion machinery of the vessel was not optimised for this speed and operating on a single main engine did not provide sufficient torque to rotate the propeller at the designed pitch. In order not to overload the engine, pitch is reduced and propeller efficiency decreases significantly.
The former centre propeller with a diameter of 4.6m was thus not being used optimally, and Scandlines therefore decided to replace the five propeller blades with smaller blades, so that the centre propeller now has a diameter of 4.2m. In addition to improved efficiency, this also reduces vibration and the risk of bottom damage.
With a crossing time of two hours, Scandlines reduces the propulsion energy and CO2 emissions by 11% thanks to the new propeller blades.
- Before: Centre propeller with a diameter of 4.6m
- Now: Centre propeller with a diameter of 4.2m
- Number: The centre propeller has a total of five blades
- Weight: Each blade weighs 1,223 kg
- Propulsion energy saving: 11%
- CO2 reduction: 11%