gps-speedsurfing

Hi all

A quick question for all you veteran speed sailors. How much of a disadvantage is a lower weight when it comes to going fast?

I weigh 53 Kg and I've looked at the speed returns for those in my catagory and it seems the lighter ones don't seem to be able to carry the speed of the heavier. My initial goal is 30 knots but it seems this isn't too far off the top speeds achieved, not that this will stop me going for it. What do you lighter guys do to achieve these speeds? Obviously I understand the general dynamics of weight against rig size etc. and I usually have to drop half a meter or so against my fellow riders on any given day but I can generally keep up with them.

To me it would seem logical that I should be able to achieve the same speeds as the heavier guys only with a smaller rig and possibly even on lighter wind days or is this just wishful thinking.

Please excuse my naivity but I only started sailing three years ago and at 57 I don't have years to spend learning how to go fast so shortcutting via others greater knowledge seems the best option.

Cheers.

hi, paul very interesting subject hope we get some more comments ,

im no speed expert by a long stretch of anyones imagination but i must add my 2 penthh worth. and i do sail quite regularly with a very light weight mate who often says the same "im not as heavy as you i cant hold the board down to go fast enough" i know to be rubbish cause he does go fast when hes a mind too.

also his jybes are usually much better than mine .i often remark to him that hes so light that his board does'nt even know hes on it . so  he keeps pulling out sweet jybes   , but when i plant my size 11s on the board to turn i have to be pricise as i can .

As far as the speed i do belive up to a certain wind speed i will be usually be 1/2 of a metre bigger sail approx than him but not always he has gone bigger than me on occasion also my board oviously will be bigger than his usually  .so i think conditions play an important part as well as wind strength.

once you get winds in excess of 30knots it seems to go out the window . hes on his smallest sail im on my smallest sail and board 80 litre if i can ride it and i believe i have an advantage due to my wieght but not much because skill level does play a big part and i think in the end skills rule. unless im talking rubbish as well ha

At 53Kg you are very light, the lightest guy I know of other than Paul's freind, is Johny Walker, he's 68Kg on his log on here but looks like less, he mixes it up with the big boys and is one of the rare guys to go over 40knts in a more open water location (ie not Southend ot WK). 5.0 and a 68L board seem to be weapon of choice whilst guys 30-40+Kg heavier are only on the next size up (5.6 & 75) so really shows that with skill and well tuned equipment you should have some great top end potential.

See a session 4 guys logged at St Johns Lake on 6th Jan this year, high averages and high top speeds, 4 skilled guys, 3 of them over 90Kg  http://www.gps-speedsurfing.com/default.aspx?mnu=forum&forum=2&val=61359

Observation of the speeds of very dedicated and skilled riders over many years has confirmed to me that 'all else being equal' the taller and heavier you are, the faster you can go on a windsurfer.

It is my understanding that physics priciples applied to the windsurfing stance confirm that observation. Essentially, larger heavier sailors have more efficent leaverage and develop a better power to drag ratio.

Of course, in practice that is not the whole story, as many lighter/smaller windsurfers have regularly gone faster than heavier/taller sailors in tne same session. That some guys can beat the odds and regularly excell for their size points to them being able to reduce the theoretical disadvantage with better skills and equipment selection and tuning, not to mention pure guts to go for it when some others decline.

When conditions are perfect for high speeds, the wind is steady and the water flat, smaller sailors will be at a disadvantage more often. When conditions get tricky, excellent gear selection, sailing skills and a go for it attitude, and the ability to spot the right time to make a run can often close the gap a lot. smiley A great example of this at Luderitz last year was a very nice young Frenchman, Gautier Bourgeois, who used all the above qualities to make some outstanding speeds and puch well above his weight class. cool

It is interesting to note that in Kite speedsailing, there seems to be no clear advantage based on sailor size.

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.
 

Fantastic replies and thanks to those who have taken the time to do so.

Looks like I'm going to have to work on tuning my equipment (read as spend a lot of money on new gear, wife permitting) to achieve my initial goal of 30 knots and do a lot more research into the whole sport of speedsailing in all it's various forms. Oh, and grow bigger balls!

One of the problems I get is air getting under the board at speeds above 25 Knots, especially in chop and the only real place on the island to achieve almost flat water is at Matas Blancas and as close to the shore as the fin will allow. Hopefully by changing the entire rig I may be able to reduce this effect and one day might be able to give you bigger guys a run for the money. Even at these relatively slow speeds it is still one of the most wonderful feelings in the world and look forward to achieving my goal with a little help from you guys.

Thanks. yes

Of course, the upside to all this is that if you check out the rankings for my age and weight you'll see that I am number one in the world in all catagories. You'll probably notice that there isn't a lot of competition though as it's a one horse race!!!  Still, as my son says, first is first whichever way you look at it. Ain't kids great.

cheekysmileycool

Great attitude Paul, thumbs up!

Hi Paul, Been thinking a bit about this, not too much to add apart from, you need some smaller kit! 91 ltrs is big for speed if you're 53 kgs. I'm 95kg and use a 63ltr. Also you've only been sailing 3years and i'm not sure how much experience you have but would guess you need more time on the water just getting a better feel for the dynamics of water and wind. One big advantage you have is that you can get more planning time on the water in moderate winds so should be able to progress quicker the us heavies! Above all enjoy it for what it is. One more thing, try and get used to using a bigger sail than you're comfortable with, you need power for speed.

Hi Tony, thanks for that and with only three years under my belt i know I've got a steep learning curve to negotiate before I can get anywhere near you vets. I'm fortunate enough to have given up the rat race (highly recommended) and live the only life I'll get on the windsurfing paradise of Fuerteventura so I get out on the water just about every day. Mostly I surf the big swells a few kilometers out and then play in the reef break on the way back in which doesn't make for much speedsurfing but is heaven on earth. I've got to use the smaller board a lot more and work my way down as I think this will give me the edge I need to achieve my goals and, as you say, get used too and comfottable with the feeling of being overpowered. In theory I should be able to achieve good speed in lower wind conditions with the right kit than the bigger guys. Bees can't fly in theory but it don't seem to bother them too much. Keep an eye on the rear view mirror!

Full moon tide, big swell, lots of wind. Guess what I'll be doing tomorrow as fast as I can!

Nice one, keep shredding and 30knots will be just a memory soon when you're pushing for forty in sotovento! 

P7