Sun Mar 30
I have a physics question for all you sailing geeks.
We all know the relationship between body weight and boatspeed in a small racing sailboat like a Laser, right? Or we think we do.
In heavy winds, let's say over 25 knots, the heavier guys do better in the races (other things like overall ability being equal). Generally speaking, in these conditions someone of 200 lbs will beat someone of 150 lbs in a Laser because the big guy can hike the boat flat upwind and will still be surfing downwind, while the little guy is struggling all the way upwind and would be better off in a Radial.
On the other hand in lighter conditions, let's say 5-10 knots, the little guy will probably be faster around the course. Upwind he may well be hiking flat out while the big guy will be simply sitting on the side deck and going slower, wallowing in the hole his heavier mass makes in the water. And downwind the lighter sailor will be soooo much faster. It's all to do with displacement and drag and Newton's Second Law, F=ma and all that.
So far so good. Please don't bother to argue with the above, because I know I'm right. I can even look at the results of the racing at my old frostbite fleet and make a very accurate guess of what the wind conditions were like based on the relative finishing positions of two (both excellent) sailors of very different body weights.
The question I have is what happens at the very light end of the wind spectrum, say 0-3 knots? I know that no race committee in their right minds would run races in these conditions... but sometimes they do. I've noticed on a number of occasions that the heavier sailors start doing well again in these conditions.
There was the time my (heavier than me) son beat me in the 2006 Laser regatta at Hunterdon Sailing Club in New Jersey, in a very light patchy easterly wind.
And it happened again on the last day of the Kurt Taulbee clinic in Florida last month. There was one other guy on the clinic who said he weighed 150 lbs while I owned up to 200. (OK, I rounded down, but who's counting?) On the Saturday in 5-10 knots he beat me easily in every practice race. But on the Sunday in a dying gradient breeze fighting the new sea breeze, shifty, patchy, and dying away to zero occasionally, I did a horizon job on him in every race.
So my question is, why? Is it a matter of these heavier sailors actually having very good light air skills (relative to the opposition that day) that overcome any weight disadvantage they may have? Or does weight actually become an advantage again in the very light stuff? Is there some kind of inertia effect which means that the heavier sailor somehow keeps coasting through the lulls, maintaining flow on the sails and foils, until the next little puff comes along?
Answers please. Do no attempt to write on both sides of the paper at once. Credit will be given for references to any physicist other than Newton and for the use of second order differential equations. Bonus points will be given for anyone quoting Stuart Walker and being able to explain the quote in less than 500 words. Anyone referencing Nietzsche, Sartre or Rilke will be awarded a failing grade.