The water surface contours show the pattern of waves generated by the moving hull. A complete yacht is visible in the animation with topsides hull and main and Genoa sails. A physical tow tank test consists of obtaining yacht forces for a matrix of sailing speeds, yacht heel and yaw, rudder and keel tab deflections. Traditional physical model tests in a towing tank are also very expensive and can easily eat away at the limited budget of any design team. Numerical model tests may deal more directly with uncertainties and complications of predicting open water sailing.
Numerical simulation can also yield more consistent results in less time than physical testing.
Yacht performance benefit due to bulb-mounted winglets . Recently there has been a bit of role reversal of CFD simulation over expensive physical testing. To produce optimal performance all these tools work best in complimentary roles. Tow tank simulations require several hundred specific sailing points to be analyzed. Scripting software collects and sorts all of the individual results.