Wärtsilä Evaluates Course-Keeping Capability of 300m Bulker Vessel

As part of the OPTIWISE vessel design activity, Wärtsilä has evaluated the course-keeping capability of the 300m bulker vessel. The baseline case is a conventional semi-spade rudder. The rudder effectiveness has been analyzed with full-scale CFD simulations, where the propeller loading has been reduced gradually. Due to the expected WASP contribution, the target vessel speed will be reached with reduced propeller loading. In line with existing theory, the effectiveness of the conventional rudder reduces due to the lower propeller wash. 

The alternative rudder configuration is based on Gate-Rudder concept. It has been found that the effectiveness of the Gate-Rudder remains constant and thus independent of the propeller loading. This is attributed to the undisturbed inflow to the rudder blades, which is related to the vessel sailing speed. As long as the vessel speed remains at target, the Gate-Rudder contribution to the course-keeping will remain constant. This is a clear synergy between WASP and Gate-Rudder concept.  

Norbert Bulten PhD

Senior Product Performance Manager, Wärtsilä