VPP-Driven Sail and Foil Trim Optimization for the Olympic NACRA 17 Foiling Catamaran

The Nacra-17 is the current Olympic catamaran sailed in the Olympic Games since 2016 by a mixed crew. Over the years, the boat has undergone some changes. The initial design of the boat featured a set of appendages that only rarely allowed the boat to foil. Today, Nacra-17 features semi-L-shaped daggerboards and T-rudders, all of them independently trimmable. This allows the boat to foil at wind speeds of 9 kn and below on an upwind tack and even earlier on a downwind tack. Trimming flexibility comes at the cost of increased complexity in sailing the boat. This project addresses this challenge by assisting sailors in identifying an optimized set of trim parameters using a proprietary velocity prediction program, which, beyond solving the equilibrium of all forces acting on the boat, searches for a combination of daggerboard and rudder rake, rudder angle, heel angle, and platform trim that maximizes performance. The method and selected results are also discussed. Keywords sailing; Nacra-17; VPP; foils; optimization