SPP™ ... uses regression analysis to calculate hull forces without existing VPP data


SPP (Sail Performance Prediction) is used to predict relative sail performance between different sail designs or trims quickly. Using SPP, designers can instantly compare the performance of a new sail design relative to a baseline mold. This allows a designer to test up to 10x the number of shapes compared to running individual designs through a large matrix of runs in Flow then coupling these results into the VPP.

Additionally the SPP can be used in cases where the sail designer was not able to acquire enough data to run the North VPP.
Chart showing increasing hydrodynamic resistance as boatspeed inceases© North Sails
Here is a plot of windage vs. Apparent Wind Speed.© North Sails
This chart demonstrates the increase in DF necessary to increase Vs by 0.1m/sec© North Sails
Here are depowering test results in 6, 8, 12 & 16kts True Wind Speed. The Driving Force slope of each test varies relative to the curve formed by sails trimmed to match a target Heeling Moment at a specific true wind speed.© North Sails