A numerical method that is successfully applied in yacht design are the genetic algorithms. The computer is used to improve a design in an evolutionary process through many generations. I presented first results of this method at the Second High Performance Yacht Design Conference 2006 in Auckland. The figure of merit was the VMG and the constraint were the costs of the yacht. The validity of the optimum depends heavily on the accuracy of the predicted speed potential of the yacht. The speed must be calculated from the geometries of hull and sails. The resistance of the hull could be predicted at that time only on the basis of the regression factors, which were developed at the TU Delft. All influences on driving- and resistance-forces are still not known though. Of great help were the towing tank test data of a Dehler 33. They were thankfully supplied by the SVA Potsdam. The status of this work as of 2012 is described here.

In the years to follow, a lot of new tank test data became available. Since the beginning of 2013 all individual test results from the towing tank at the TU Delft are available on their website. This is a new invaluable knowledge base. Based on this experimental data and an additional boundary-layer calculation, I developed a new correlation for the residual resistance. A prerequisite for this task is explained here, the theoretical background and the results of the regression analysis can be found in this report. The database was increased by adding the towing tank results for the Delft-372 model. UliTank is a computer program that incorporates all the newest findings. In 2015 the Sailing Yacht Research Foundation published on their website towing tank results that were conducted in 2003. I used these results to increase the database of the regression analysis for the new version UliTank_3.3.This new version computes the resistance with appendages in the heeled attitude and with leeway. UliTank_3.3 can be downloaded  here.