it all depends on how you define F4.
I merely want to point out once more that wind estimations, purely based on the visual, can be really deceptive. Yesterday, we had unbelievable wind variations, because of SW wind combined with a lot of showers. When I arrived at my spot, my first impression was 6Bft. Yes, there were gusts up to 25 knots, deluding the water state with magical white caps. But these were merely gusts. 80% of the time or more, the average was only 15 knots, sometimes dropping to hardly 12 knots.
I've seen a lot of guys shlogging in the lulls with too small sails 5.xm2.
IS87 / IS101 / IS122 / US147