I really depends what sort of sailing you are doing. I'm either sailing in the waves or doing freestyle so I always use the smallest sail I can get away with, regularly i'll be 2m^2 or more smaller than others out there but am still planing around quite happily. Sure, if it comes to a drag race I don't have a hope but it's just not the sort of sailing I do. If you are looking to sail fast or sail extreme angles (formula) you need as much power as you can hang onto, hence the big sails. It's horses for courses, if you're happy sailing with what you have, sweet, you probably won't win a drag race but you might be able to bust out some rad freestyle

Went sailing the other day after checking the forecast. Took down the 7m as the forecast looked grim, I wish I had something bigger. But what do you know when I got there it was blowing so I downhauled the hell out of it.

Some lucky guy I've not met before had a 5m.


____

I rigged too big on Boxing Day and had a *fantastic* sail, on the Gold Coast Broadwater. As said above when powered up with both a big sail and fin you can get some crazy angles happening. I was easily running from the bridge at Labrador down past Shearwater (stradbroke side) and back. The guys on smaller gear where doing the usual 300m run at Shearwater.

PS I appreciate efficiency, but sometimes being overpowered, screaming downwind and not being able to sheet out can be exciting.

Thanks decrepit, the winds down here do tend to be on the gusty side and that may be the reason some guys use the larger, flatter rigs.
I prefer to use a lighter sail and will stick to what I am comfortable with. I was just curious what advantages were had with the other rig set-up.
By the way, CJW, a few good gybes would be good enough for me.

stehsegler said...


In regards to wave sailing I have to agree with CJW. Going bigger isn't always better... for example going from 5.6 to 6.2 will mean bigger mast (= more weight), more sail weight, more drag. That alone will probably kill any advantage of using a 6.2.

On the other hand going from a 4.5 to a 4.0 is a big difference. Something to do with the force of the wind increasing exponentially... but I won't bore you with the details of that.

Yes there certainly seems to be a diminishing return when you get to certain sizes in wave sails. I'm yet to find a wave sail over 6m that I feel offers any advantage over say 5.7, but the disadvantages are there.

Not sure this is true for race sails however.

stehsegler said...


On the other hand going from a 4.5 to a 4.0 is a big difference. Something to do with the force of the wind increasing exponentially... but I won't bore you with the details of that.

Stegs, I'll help you out, because I don't think you would be able to explain it on your own.

It's interesting stuff, give people some credit, I don't think anybody would get bored.

But it was probably best you didn't provide any details because it's too hard to explain aerodynamics in sentence form. Here is the Formula.





As you can see, the Lift (force) of the sail goes up or down in a linear fashion with sail area, when you have the same type of sail, in the same wind, at the same angle of attack.


This formula also answers the OP. It's all about the lift coefficient (CL). You can generate the same lift from a smaller sail by sheeting it in more, but you loose efficiency, this is why Slalom sailors always run a larger sail at a lower angle of attack, they have a better lift to drag ratio. That floppy leech is good..

Iceman said...


I noticed that they were using a great deal more downhaul than I was. I was setting my sail as per what I imagine the manufacturer recommends, loose at the top but not overly floppy. Their rigs were very loose and so they would only be using half of the power available for them, the rest being exhausted in the loose leech.

With the leverage we have over the rig, it's imposible to utilise any extra power generated at the top of the sail. The top is there to hold the bottom up, the bottom generates the useable power..

You get more lift with less downhaul because the sail is fuller all over, your not really getting extra lift from loosing less out the exhaust.

barn said...
Stegs, I'll help you out, because I don't think you would be able to explain it on your own.

Yeah... I guess the 6 years of physics at uni was a waste.

AUS02 said...

These bigger race sails can handle it if it does get windy as they have a huge range, so it's OK to rig a 7.0m in 15-25 or a 6.2 in 25-35, even though a smaller sail on a free-ride board will feel totally powered up in the same conditions.

What I think you are saying Dave is that it is not so much the way the sail is tensioned, it is the type of sail you are running. My sails are wave sails and they will not respond in a similar way to a race sail when tensioned in a similar way. In other words I should not just really wind down my 6 metre and venture out in 30 knots of wind.
Oh by the way, no I'm still not getting a GPS.
Catch you at Stanley.