Selecting a Keel Appendage for a Cruising Yacht From a Standard Keel Series

The purpose of this paper is to describe the results of model tests for a series of three keels; two at constant draft; two at constant aspect ratio; all at constant taper ratio and thickness ratio. These keels form part of a standard series developed by Pierre De Saix at Davidson Laboratory, Stevens Institute of Technology in 1974 and originally tested on a 5.5 meter hull (1). The three keels were all tested on the model of a small cruising yacht over a range of heel angles, leeways and speeds. An analysis is made of the expanded model data and a comparison presented of the forces and moments operating on the deepest keel and the two keels of constant draft.