Comparative Performance Prediction of Historical Thames A Rater Class Designs

Abstract

The Thames A-Rater fleet is a unique class both in appearance and in its combination of historic and modern technologies. With high aspect ratio, carbon fibre rigs fitted onto wooden hulls, many of which have survived two World Wars, the class is a demonstration of the evolution of sailing technology. In more recent decades, various attempts have been made to expand the class with new composite boats. However, due to the strict rules issued by the class association, new hulls must be exact replicas of existing A-Raters, with a 1.5 inch tolerance. Furthermore, as only one linesplan exists in the public domain, the expansion of the fleet is extremely limited. Consequently, in order to ensure the conservation of some of these historic designs, the lines of several vessels were taken off and used to create accurate linesplan and 3D models. The comparative performance of the various crafts was then assessed through a Velocity Prediction Programme, focused on the specific environmental conditions of the vessels' main operating area, eventually ascertaining the hull with the best racing potential by design.