gennaio 2011

SCHOTTEL Combi Drive for Svitzer’s ECOTUG®

Environmentally friendly solution with an electric azimuthing thruster


360 degree steerable propulsion units are increasingly being used in diesel-electric powered vessels. Even tugs with relatively high bollard pull ratings are now being equipped with diesel-electric systems. With the Combi Drive, SCHOTTEL is offering a compact and reliable solution that sets a trend in terms of its ecological standards.


The Danish shipping company Svitzer is one of the pioneers in the field of environmentally friendly tugs. Among other things, the company’s environmental policy already includes an annual reduction of CO2 emissions.

The two ECOTUG® are currently being equipped with a dual system in the stern, comprising SCHOTTEL Combi Drive SCD 1515 thrusters. To meet the application requirements, the single propeller version of the SCD with nozzle was selected. This version of the Combi Drive lends itself particularly to situations where static thrust and part-load operation are required. Each of the SCD thrusters has an input power of 2100 kW at a speed of 700 rpm. Three independent generators supply the propulsion system with energy. If sufficient for the task in hand, only one generator is used. Additional generators are then activated as required during operation.

The SCHOTTEL Combi Drive is based on the SCHOTTEL Rudderpropeller, a concept that has already proven itself over many decades. In addition, a frequency-controlled electric motor is vertically integrated into the support tube of the Rudderpropeller. This means that the Combi Drive, like the L-type Rudderpropeller, has just one reduction stage, resulting in increased mechanical efficiency. At the same time, the SCD offers the same compact design as a Z-type Rudderpropeller. The result is a powerful azimuthing thruster that eliminates the need for an above-water gearbox and shafting, and sets itself apart due to its slimline and maintenance-friendly design. The shipyard also benefits from implementation of the SCD: the propulsion system is easy to install and no motor foundation is required.

The thrusters are operated in conjunction with SCHOTTEL steering and control systems (SST), which allow the course direction and azimuth angle to be set, and various operating and control modes to be selected.

The ECOTUG® is equipped with a SCHOTTEL Transverse Thruster of type STT 110 with fixed-pitch propellers powered by an electric motor. This manoeuvring aid enables the thrust direction to be reversed without the need for an additional reversing gearbox. The input power is 190 kW at a speed of 470 rpm.