System-based modelling of a foiling catamaran

Abstract

In the last decades, the use of foils on sailing yacht has highly increased. Whether they are mono or multihull, yachts are using foils to reduce their drag forces and then, to increase their speeds in a large range of wind and sea conditions. Several CFD-based studies have already been carried out in order to optimize the foil's shape and location on the hull, but feedbacks on the yacht's behavior is mainly given by the crew when sailing at sea. The aim of the present paper is to propose a complementary and faster approach that could help to predict and quantify the yacht behavior in calm water and in waves while sailing under foil's action. This approach is well known as a system-based modelling and is a mathematical method that leads to understand the complexity of a system from the study of its interactions in their entirety. The paper will present the ability of the system-based approach to predict the attitude of a catamaran while performing maneuvers such as turning circles with 35 degrees of rudder deflection and zigzag tests 10-10 and 20-20 for different initial Froude numbers and foil's shapes.