The diesel drive provides the energy, whilst the electric drive line provides optimum load distribution and speed. The combination of these principles has for decades represented the most flexible configuration for a ship’s drive.
Now Sensor-Technik Wiedemann GmbH (STW) has taken the next step. For the first time, a hybrid drive for a passenger ship with two completely independent energy storage systems and engines has been created: with one diesel main drive and a battery-powered electric auxiliary drive as a maneuvering aid and emergency drive. zebotec GmbH from Constance have assembled an innovative, electric drive unit from Sensor-Technik Wiedemann key components, which functions as a 360° bow thruster and is also able to move the entire ship on its own.
The Bohemia Rhapsody, a passenger ship from the Derben dockyard in Saxony-Anhalt, is 45 meters long, displaces 123 tons of water and provides space for 220 passengers. She was put into operation as planned for the 2015 season, and is now deployed at PRAGUE BOATS on the Vltava river. As the narrow river places high requirements on the maneuverability of this large ship, it was clear in advance that it could only be controlled using a 360° bow thruster. The safety assessment revealed that a completely independent auxiliary drive was needed which could keep the ship maneuverable even if the main drive were to fail. It quickly became clear that the best concept for the fulfilment of all requirements would be a pump jet which would be electrically operated on battery power. It is emission-free and energy-efficient; in addition it proved easy to accommodate into the available construction space. The 226 HP main drive is thus supplemented by an electrical 110 HP auxiliary drive which is able to run the ship at full power for 30 minutes thanks to a lithium-ion battery.
“This drive solution, which functions without external units, is unique. In addition, this hybrid approach with the conventional diesel engine and the energy-efficient electric drive contributes directly to environmental protection”, says Dietmar Schrägle from STW.
“The maturity and compatibility of the STW components are the reason why the project could be so quickly implemented”, adds Richard Morris from zebotec. STW supplied the battery management system mBMS for the lithium-ion batteries, the electric motor power MELA C-80 and the drive control unit ESX-3XM.