Producer's Notes: Physics of sailing
Editor’s Note: Guest blogging for Producer Joan Johnson is QUEST team member and sailing fanatic Sandy Schonning.
The real physics of sailing are so deep and so complex, people
are still debating it.
It was another average Tuesday. I was sitting at my desk, looking at my calendar. Another day of budget meetings, returning emails, reviewing contracts, yawn. The usual buzz of production was going on around me, a crew going out to do a story about… sailing. Ah sailing, my favorite topic. My husband and I had recently moved both ourselves and our Tayana 37 up the coast from Long Beach. Okay, a well-qualified captain had actually moved the boat to San Francisco for us… but since Polaris had gotten here, we had become a bit obsessed about Bay sailing. Sailing in So Cal had not prepared us for the currents, tides and winds of the Bay, so we tried to get out there as much as possible.
Okay, back to Tuesday morning. The buzz moved over to my desk… the shoot was supposed to show a group of beginners on a sailing lesson, but the family that was booked for this purpose had suddenly cancelled that morning. Could I fill in? I considered my clothes… skirt, heels, not really sailing clothes. And moving all those meetings… but a day on the Bay… the beautiful, sunny, windy Bay. Plus, sailing with an instructor, there is always something to learn about sailing, how could I pass this up? Okay when are we leaving? No wait, what am I going to wear… isn’t there a West Marine near the sailing school. Can we stop to get me pants and a pair of shoes? Yes, that’s how much I really wanted to go out that day, I bought new clothes to do it.
It was a great day on the Bay. Stan, our instructor from the sailing school, was great at explaining the physics behind why a boat sails. At the direction of the producers, I asked every sailing question I could think of. Who has the right-of-way, what is this line for, what do we do when the wind blows harder? Okay, I knew many of the answers, but I babbled on anyway. Was I having fun? In much of the segment, I have the goofiest grin on my face. I wish I had a job that took me sailing every day…
Anyway, it was over too quickly - and then it was back to my meetings. But I’ll tell you the biggest surprise of the whole experience: I though the physics behind sailing were pretty simple - a little Bernoulli Principle, a little lift generation. But what I learned made my head spin. It turns out that most of the simple explanations of sailing physics are ‘helpful models’ that make sailing understandable to sailors. The real physics of sailing are so deep and so complex, people are still debating it. If you’d like to see what I mean, check out Arvel Gentry’s website. Gentry was an aerodynamicist for 40 years, is an avid sailor, and an America’s Cup boat designer. His technical papers will give you an idea of what’s really going on:
Hi!
Did just watch this TV-episopde, great! But does it explain how a plain can fly upside-down? :p
plane, not plain, of course :D
Sure. The only problem is that the wings need to be at a higher angle of approach due to the non symmetric wing shape. The up-side-down wing does however give lower efficiency as the wings are usually optimized for best lift/drag ration in the normal flight situation :-)
Sorry I didn’t respond earlier, I have been out of the country. But as the second blogger points out, aerobatics planes have symmetrical wings, so can generate lift in either orientation. However with symmetrical wings a greater angle of attack is required for it to generate lift. And that’s about all I know about that. ;-)