The new Schottel VarioDuct SDV45 high-performance nozzle is now available in the Rudderpropeller range from the German propulsion specialist. Schottel says it offers provable higher efficiency at open-water speed combined with ‘very good bollard pull’ values.

Model test of the new nozzle Schottel VarioDuct SDV45 in the towing tank

Model test of the new nozzle Schottel VarioDuct SDV45 in the towing tank

In conjunction with optimally designed propeller geometries, and the same propulsive power, it has a greater bollard pull than the thrust of previous nozzles and, at the same time, offers considerably greater efficiency in the medium and high speed range. The system, consisting of a Rudderpropeller and the new nozzle, thus contributes significantly to fuel savings.

The VarioDuct, with its compact geometry, offers considerably greater power than standard nozzles, such as the Wag-19A; it can also be optimally adapted to different vessel designs and applications. The small outer diameter also makes the nozzle ideally suited to shallow-water operation.

This improvement in efficiency is largely due to the latest computer-based CFD (computational fluid dynamics) methods which Schottel applies for flow simulation. During the development of new products, CFD calculations are used to investigate hundreds of geometry variants and thus determine the optimum design. This geometry is then tested by means of model trials to demonstrate the operating characteristics. Schottel uses CFD and other computer-based, three-dimensional calculation methods for the in-house development of custom-tailored and optimally coordinated propulsion systems for virtually all vessel types and applications. On the basis of extensive experience, hydrodynamics specialists optimize the systems in terms of power, durability, compactness and fuel savings in accordance with customer project requirements.

By Jake Frith