Images © Van Oossanen & Associates b.v.

Late in 2003 we completed an extensive study into the possibilities for further optimization of a Lemsteraak. This was done for the case of maximizing the absolute speed and the case of maximizing the speed under the rating rule in use.

For this study we made extensive use of the vast amount of data we have obtained from towing tank tests with a systematic model series and examining various rigs and the influence of the rig's dimensions in the windtunnel.

The research was started by analyzing the design and performance of the best yachts currently in the fleet. These yachts were analysed using a VPP, combined with the results from the towing tank and wind tunnel experiments. This gave additional insight into the various parameters most important in the design, and their influence on the performance.

The second stage of the project was to make a systematic variation of these parameters, and again doing a large number of VPP runs. For these runs, use was made of the mathematical models derived from the obtained experimental data. Also, a sensitivity study of the TVF rating factor was made, to look at the influence of the various parameters involved.

The results were very promising, as the graph above points out. Depending on wind speed, a rating gain of over 50 seconds per nautical mile is possible, relative to the best current yacht, on an olympic triangle.