Hardware in the loop experiments with ship propulsion systems in the towing tank: Scale effects, corrections and demonstration

Standards for environmental impact, safety and operational performance of ships are becoming increasingly strict. In order to meet these standards, the performance of new ship designs must be predicted with an increasing level of detail and confidence. As present prediction methods lack realistic, dynamic behaviour of the ship's propulsion plant, there is a need for more advanced methods. In this paper, an open water test with Hardware in the Loop (HIL) functionality is proposed. HIL open water tests combine software and hardware components to emulate realistic behaviour of the ship's propulsion plant in the towing tank. It is known, however, that experiments in the towing tank are subject to viscous scale effects. In addition to this, shaft dynamics are distorted by a number of scale effects occurring inside the scale model propulsion system. In this paper, it is demonstrated with measurements that if corrections for these scale effects are applied, the dynamic interaction between the propeller and simulated engine system can be accurately emulated in the ship model basin.