Yesterday's wind forecast was light, but it predicted a slight increase in the late afternoon. When the local wind meter readings increased to 11 mph, Nina suggested to try foiling with her 7.5 m longboard sail to find out how low she could go. Here's yesterday's wind graph:
By the time we were rigged and ready to go, meter readings were down to 8 mph. This may be foilable for PWA pros with huge sails and foil boards, but Nina only had 3 or 4 foil sessions on our gear, and fewer than 15 sessions overall. For more than an hour, her board stayed solidly in the water, except perhaps for a couple of seconds after vigorous pumping. But then, the wind picked up just a bit, and for 20 minutes or so, she was foiling most of the time, getting nice, long, controlled flights. When we got back home, we looked at the wind graph:
The highest wind average reading was 10 mph, gusting to 12, for about 10 minutes (9 knots gusting to 10.4). To plane on windsurfing gear, she usually needs at least 13 mph on the big slalom kit, and perhaps 18 for her freestyle gear.
Foiling in 10 mph with pretty limited experience is pretty impressive. The sail certainly helped - it's extremely light, has a deep profile and a tight leech, and soft cambers. But it was not rigged quite right, and Nina has not yet figured out how to pump it really well with the foil, so there's some room for improvement. We also just ordered a Slingshot Infinity 84 foil, which is larger and should lower the planing threshold a bit more. Hopefully, though, the larger foil will mostly help to get me going in similar light wind. Even on foils, bigger guys need a bit more power...