SCHOTTEL’s SRP-D rudder propeller optimizes dynamic positioning for offshore wind applications

ATA designed a gear solution for a very special axle angle

With a new rudder propeller optimized for dynamic positioning, SCHOTTEL is meeting the growing requirements for the specialized Walk-to-Work offshore support vessels equipped with motion-compensated gangway to operate efficiently and reliably. These vessels can serve as mobile accommodation, workshop and warehouse, safer and more efficient than helicopter or crew boat transfers. The SRP-D further improves the highly demanding DP operations in these service operation vessels. When developing the SRP-D, SCHOTTELS’s specialists utilized and relied on extensive Computational Fluid Dynamics simulations and calculations. ATA’s Gear Doctors contributed by designing a gear solution for a very specific 98-degree axle angle.

Thanks to the lower gearbox design of the SRP-D with an additional eight degrees downward tilt, the propeller flow interaction between propulsion unit and hull and also the interaction in between the thrusters are reduced. The 98-degree tilted propeller shaft improves thrust efficiency in DP operation and minimizes “forbidden zones”.

“Based on the proven principle of the SCHOTTEL RudderPropeller, the cost-efficient yet powerful SRP-D vastly improves the positional accuracy of the vessel for the special requirements of offshore service applications,” declares Martin Schneider, VP Technology at SCHOTTEL. “In demanding weather conditions it is a matter not only of performance but first and foremost of safety and operability.”

Highly dynamic thrust allocation

The SRP-D is mainly characterized by reduced propeller acceleration/deceleration time. In combination with a high-speed azimuth steering system with reinforced gear components, the SRP-D enables faster thrust allocation than conventional rudder propellers. Shorter response times enable faster, better-targeted reaction to external forces from wind, currents, and other weather phenomena, thus ensuring a higher positional accuracy of the vessel. At the same time, energy demand is reduced.

Compact and efficient: LE-Drive

The SRP-D has an extremely low profile, vertically integrated LE-Drive as well as an additional eight-degree tilt of the lower gearbox. Thanks to its compact design, the LE-Drive allows more freedom in vessel design. The SRP-D is also available with optional drive train in Z-configuration. And ATA’s design met these requirements, too.