Simulating sail forces when free pumping in the Olympic Finn-dinghy.
Note: Tripling the sail force does not mean tripling the boat speed. All the simulations were done at a similar speed range, varying around 4 kn (the boat speed is not constant). In reality, with free pumping boatspeed will be higher, which means apparent wind speed will be lower, which means the sail force will be less. The problem is circular, a more accurate solution for boatspeed would need iteration rounds.
A few iterations with a VPP suggest that the boatspeed with free pumping will be around 5.5 kn, or an increase of 37%.