Everyday Scientist

the physics of sailing

February 21, 2008 at 7:39 pm | sam | journal club, science@home

The cover story of February’s issue of Physics Today, the publication of the American Institute of Physics, is the physics of sailing. I like sailing: grew up on the coast of Maine sailing Lasers—and eventually and Ensign—every summer. Obviously, I can’t afford to sail out here in San Francisco, but I get to go home every summer and sail in Casco Bay.

I thought the cover of Physics Today was a little cruel: “Hey you, in that dark laser lab, check out what these smart people are doing: Sailing!” But the article was actually pretty cool. The basic stuff was in there, and it even had equations (like Reynolds number). But really, I just looked at the figures.

This is a helpful one: you can go faster on a beam reach than when running downwind. If you don’t realize that a (modern) sailboat is wings on the water, going directly downwind is what you would intuitively want to do. And going upwind is mind-boggling.

But my favorite figure was this image of sailboats racing in the fog:

The beauty of vortices trailing off in the fog for thousands of feet was stunning. I also like that you can see that the third boat from the top is tacking and temporarily interrupting the trail. Cool.

Well, here’s a PDF of the article if you’re interested.