Schottel’s new DP-optimized rudder propeller

With an aim to meet the growing requirements for walk-to-work (W2W) vessels to operate efficiently and reliably, German marine propulsion specialist Schottel has developed a new rudder propeller optimized for dynamic positioning (DP) use. The SRP-D (Dynamic) is a further improved variant for highly demanding DP operations in service operation vessels.

The SRP-D rudder propeller for dynamic positioning applications. (Photo: Schottel)

“With the SRP-D, we have significantly increased the DP performance of our rudder propellers, resulting in a product that meets the requirements of today’s offshore wind industry even better,” said Manfred Heer, VP Technology at Schottel. “Based on the proven principle of the Schottel RudderPropeller, a cost-efficient yet powerful solution has been developed that greatly improves the positional accuracy of the vessel for the special DP requirements of these applications. For customers, this means a significant increase in safety and possible operating times on offshore structures, especially in difficult weather conditions.”

Highly dynamic thrust allocation

Schottel said the new SRP-D variants, which were developed using extensive CFD simulations and calculations, are most characterized by reduced propeller acceleration/deceleration times. In combination with a high-speed azimuth steering system with reinforced gear components, the SRP-D enables faster thrust allocation than conventional rudder propellers, the company said. With shorter response times, it is possible to react faster and in a more targeted manner to external forces from wind, weather and currents, thus achieving a higher positional accuracy of the vessel, the company said. At the same time, fuel consumption is reduced.

In addition, the SRP-D is marked by its extremely low profile, vertically integrated LE-Drive (embedded L-drive) as well as an additional 8º tilt of the lower gearbox. It also helps reduce fuel consumption, the company said.

Despite its integrated design, the LE-Drive allows a free choice of motor for electric-drive vessels. With a compact design, the LE-Drive opens up more freedom in vessel design, Schottel said, and the SRP-D is optionally available with drive train in Z-configuration.

Thanks to the additional lower gearbox with the 8º downward tilt, the interaction between the propulsion unit and hull is reduced, as is the propeller flow interaction are reduced. This, the company said, results in increased thrust efficiency in DP operation and minimizes “forbidden zones.”

In addition to recently delivered service operation vessels such as the Wind of Hope, the Bibby WaveMaster Horizon or the installation vessels Voltaire and Les Alizés which are currently being built for Jan De Nul, Schottel said it has delivered propulsion systems for more than 600 offshore vessels.