Quick question just seeing how much power difference there is between a 6.6 sail and (say) a 7.4, both being Freeeride flat water sails. My biggest sail is a 6.6 and I've worked out I need a steady 12 knots to plan comfortably, so would a 7.4- or there abouts- get me up and planing in say 10 knots, or will it simply be better for keeping my planing on those marginal 10-14 knot days?
Cheers guys.
Phil, if your 6.6 (I think I know the brand) freeride can crank you up on the plane with 12 knots, the 7.4 will do it as long as you have steady breeze. 10 knots is rather light. My 6.6 wont work unless its around 14-15 and the 7.4 not much use below 12 knots. But yes you wiull get more out of a 7.4 in lighter breeze.
I was given a tip by Guy Cribb, get onto a 2-3 cam sail same size as soon as you can afforrtd same. Freeride are OK but the cam sail sooooo much better
6.6 planing in 12 knots! with a 7.4 you could compete in the formula series.
does thta mean new and mast boom. if so probably not worth it.
I think sail and wind forces work on the square power (surface), so a 7.4 would have a bit less than 30% extra power, all rest remaining equal. On the other hand between 12 and 10 knots there is over 40% power reduction, so you would not be able to plane in 2 knots less wind. This is a very rough estimate, I take no responsibility for what I am saying, i am sure that other scientifically inclined windsurfers can elaborate better. Also there is a handy sail calculator available on the web.
Hi Phil,
yesterday I used a 6.6m and 7.3m sail, my new sails. Initially I used the smaller sail and my smaller board but I kept dropping off the plane. The wind was there but it wasn't enough to get me going all the time.
So I swapped to the bigger board and sail. I was planing all the time and had plenty of power, even on big downwind broad reaches of over a kilometer. Plenty of power coming back upwind too.
It was getting a bit much for me though, the wind was picking up. I'd guessimate about 25 knots. I was sailing overpowered which is fun but gets a bit full on. So went back to the 6.6m. Well powered up again however with a bit more control which was good as I was feeling a bit buggered by then.
So to answer your question, I think if the wind is there but you can't get on the plane and you want to, then a bigger sail is the go. However if you are on the plane and have plenty of power, then you don't need a bigger sail.
Honestly I'm not really sure about wind speeds. I've ordered a wind anometer from an online store. It should arrive this week. I hope the thing works as I'm keen to actually know how strong the wind is when windsurfing.
I think most wind readings are taken from the tops of poles and buildings, so there could be a big difference between the observed wind speed and the actual speed on the water.
Cheers for any info.
Hey Moby,
You mentioned using a 6.6 then a 7.3 yesterday. Are you happy with that size gap- or in hindsight would you have gone a tad bigger / smaller gap?
I sailed yesterday in what I figured was anything from 10-15 knts, (pretty gusty really) with some squals going 20 plus. But who knows, may have been 12-18, or 8-13??? Keen to hear how your anemometer works out- would be good to stop guessing. Can you post something about it when you've given it a run?
Dunko, I'm a bit of a light weight and seem to get going when others are slogging. Perhaps my "12 knots" is really 14....dunno, need one of those wind thingys Moby mentioned.
There's nothing dodgier than the average windsurfer's estimation of wind speed. I always laugh when I see people posting about sailing 7.5m in 20-25 kts, or planing in 15 kts with a 5.2. Almost everyone overestimates how strong the wind is (18 kts becomes 25) or how light it is depending on the story they are telling.
Get an anemometer and have a big reality check. Then, when you've discovered that the wind you told you GF was 25 is really only 20 put it alongside one of a another brand and be amazed at the variations between the two.
then I'll measure it and its 15 - 20kts..
6.6 to 7.5 is the step most people take for lighter wind. I wouldn't choose an interval any smaller than that. It will get you planing in a couple of knots less wind and give you better speeds in 12 knots than your 6.6.
ah good point, i was just thinking in terms of E = 0.5 mv^2, forgot that in this case m = Avp.
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or eat it (absorb) ? tasty and easy in classical physics.
OMG! cant stop laughing!
Poor Phil! He just wanted to know if a bigger sail was worth spending some hard earned on, instead he got a nuclearwindphysicsmathamaticalsciencecomprehensiveanaylisisonrelativewindspeedv'ssqauremeteargev'sterminalvelocity report!
Dear Phil,
Yes the bigger sail will help in lighterwinds, if you are going in light winds already on a 6.6 you will really notice the difference in sail size buy going up to a mid 7m, you will then probbaly use your 6.6 only on stronger days!
Happy uncomplicated sailing!
tasty and easy in classical physics.
Bigger sail, go faster in light wind- got it
On Sunday was struggling to get planning on my 60cm wide sonic and 6.3m in 14-15 knots. Swapped boards to my 69cm wide Fanatic Falcon with 44cm fin,also reduced a little the downhaul on the 6.3m. Was not only planning but pretty powered up.....amazing.
Swapping over from a 6.6m to 7.4 will make a reasonable difference provided you have enough board size to support the larger sail. A 2cm or so larger fin probably needed to,otherwise your board may feel like it's sliding rather than lifting.
sorry..
