Over the last few weeks, San Francisco Bay has shifted from winter to summer conditions. In the winter, we have light to moderate winds unless a storm is passing through. Sometimes we have so little wind, there are no waves and hardly even ripples in the water – the Bay looks like a mirror. In the summer, when California’s Central Valley heats up, the air rises creating a vacuum, and the only place where fresh air can pour in is through the Golden Gate. That brings winds steadily blowing 25 knots (just under 30 mph) and often gusting into the mid 30s. The wind pulls in a cool moist marine layer from the ocean that forms fog as it moves over the Bay creating natural air conditioning for the City.
We often see boats out on summer days with full sails up, no reefs. They are usually heeled far over away from the wind with the rails in the water. That kind of sailing can be exhausting as the boat tries to pull into the wind, a condition called weather helm, and whoever is at the wheel struggles to keep on course. Even though that may also look fast, it usually is a slower angle for sailing than keeping the boat more upright.
My boat has a strong weather helm and when I first got it, I always went out with too much sail up in the summer not realizing that I was making things worse. My mainsail adds to the weather helm, but the jib pulls the opposite way and gives a lee helm, so the trick is to find the right balance when reefing the sails. Now I go out with a handkerchief sized piece of the mainsail up, but more of the jib, sometimes all of it. That gives a beautifully balanced boat with no weather helm that stays on course with virtually no work.