Here's a very interesting note re sailor weight from one of the fastest guys.
It was on another forum several years back.
No offence to the big guys claiming that size doesnt matter... but the physics of it show quite clearly that weight and leverage => higher speed (or should). Really- its pretty hard for big guys to prove this since its harder for them to take 10% of their weight off and go for another run.
All the top speedsailors (including Dave "size doesnt matter" White at 125kg) wear extra weight when speedsailing- especially during competitions, and even when the wind is light. hmm if size didnt matter then why do these highly skilled and well trained athletes wear weight? Let me assure you its got a lot to do with proven testing.
Every time I put weight on for the same gear, I go faster. Sometimes as much as 3 or 4 knots for only 8kg of lead-based leverage. I wouldnt have gone as fast as I have if I were smaller. I wouldnt have gone as fast as I have without extra weight. If you are not going faster with lead on it means you are underpowered or something is not balanced with your equipment. Its as simple as that.
Some reasons:
1) forward accelleration/forward force is proportional to leverage
2) leverage is proportional to weight.
3) drag is *not* proportional to weight
The problem lies here. A given board trimming at a given angle with a given wetted area generates a fixed drag. That given board requires a certain weight to balance the nose lift, and the tail lift (which is required to balance the upward aerodynamically induced pitching moment of the nose). This has nothing to do with rider weight- ie a heavier rider needs to apply the same weight to the tail of the board to balance it, as a lighter rider. That means the board drag is a relative constant. Smaller boards => lower drag.
Fins: With any significant laminar flow the drag is relatively constant up to a certain amount of lift (shown as the "drag bucket" in lift/drag graphs). Now we are limited by fin length due to the tail width of the board- this balance needs to be maintained. So we generally choose the fin based on its length for a given board to keep it balanced. Huge guys tend to use roughly the same fin size (+/- 5%) as even the really small guys in proper speed conditions, meaning the bigger guys (requiring more lift from the fin) are getting more lift for roughly the same drag as the small guys due to the drag bucket. Another win for the heavy guys.
So far thats the board and fin giving approximately constant drag regardless of rider size...
The sail is the only part where the drag scales with lift. And this is the only area where small guys can scale with the big guys.
Dynamics: Another thing that favours the big guys is not only is their accelleration greater, but because of the extra mass, the board impacts with chop (which produce the same forces for everyone- big or small) are easier to control. Also, the decelleration is also lower (due to the higher momnentum for the same drag). So overall a heavier guy is going to accellerate more, and hold speed for longer through lulls and chop.
Light guys who chuck on a weight jacket notice immediately the increased control in chop, and the exrea power in their hands. The only problem with weight is its a lot harder on the body to move around, and sailing is very dynamic, so you get tired quickly unless you are fit and have trained with weight on.
Accelleration is proportional to leverage (height*weight).
Decelleration is inversely proportional to weight.
Sail drag (ideally sized and rigged for the rider) is proportional to weight.
In constant wind and flat water conditions, tall with high leverage is king (accelleration).
In gusty conditions, heavy is king (if the rider has the skill to keep weight off the board and on the rig) due to the lower decelleration in lulls and chop.
Weight jackets increase leverage and weight.
So there ya have it. If you are a lightweight, dont be upset if a big guy keeps stomping on your speeds. He/she SHOULD be faster. If you are a light guy keeping up or passing the gorillas then you should be proud. Because it means that you are sailing with better tuning and balance than they are. If you are a big guy getting beaten by Daffy, then its time to HTFU and use a bigger sail
What matters is that we are challenging ourselves to do better. Faster is more fun, and we can all go faster. Its the never ending quest... The feeling of flying over the water relates to finding that optimum board loading where the board drag is minimised and the rig supports our weight. The more we feel that, the more fun we have, and the faster we go.
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