Performance prediction for sailing dinghies

This study describes the development of an approach for performance pr ediction for a sailing dinghy . Key modelling issues addressed include sail depowering for sailing dinghies which cannot reef; effect of crew physique on sailing performance, components of hydrodynamic and aerodynamic drag , decoupling of heel angle from heeling momen t, and the importance of yaw moment equilibrium. In order to illustrate the approaches described, a customised velocity prediction program (VPP) is developed for a Laser dinghy . Results show excellent agreement with measured data for upwind sailing , and correctly predict some phenomena observed in practice . Some discrepancies are found in downwind condition s, but it is speculated that this may be related at least in part to the sailing conditions in which the measured data was gathered. The ef fect of crew weight is studied by comparing time deltas for crews of different physique relative to a baseline 80kg sailor. R esults show relatively high sensitivity of the performance around a race course to the weight of the crew, with a 10kg change contr ibuting to time deltas of more than 60 seconds relative to the baseline sailor over a race of one hour duration at the extremes of the wind speed range examined.