VOR boats, why not double headsails all the time?

Aug 2, 2010
502
J-Boat J/88 Cobourg
Watching the various bits on the internet, I see the boats flying two headsails fairly often and it looks to be fantastic. The sails seem both to be drawing well and the main is also drawing well, so I wonder why they don't do it all the time? I can understand downwind conditions might not suit this set-up but more sail area should be better than less if everything is working properly, shouldn't it?
BTW, it is nice to have friends to discuss this stuff with so thanks!

Dan
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
I wonder why they don't do it all the time?
The simple and straightforward answer is that is not as fast. They do it only when its faster.

The reason why is complex. It will generally work in certain apparent wind angles, and when the boat is going fast. Most mortal boats do not see theses angles with their spinnakers up, so never get the chance. But most racing Asym-boats (J/70 Fareast28r) do, and on those boats the simple rule is, if the boat is planing the jib stays up.
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Here's a fun chart to show where it can happen. This is a Sail Chart, then shows what sails can be used in what wind speed and angles. Its actually a graphical view of VOR65 data that is fed into the weather router, so the SW can use the correct sails in its calculations. You can see the overlaps in the 90TWA ranges once the wind comes up.

sail-chart.jpg
 
Jan 1, 2006
7,039
Slickcraft 26 Sailfish
I'm not used to reading charts like this but I'm interested in that all the sail combos start at a little over 30 degrees. I can't read the bottom which show which sail combinations correspond to the chart colors. But I find it interesting that all combinations provide close winded to off winded sailing at around 150 degrees. I'm used to thinking of upwind and downwind sails. But the yellow band, for example, is a very versatile set up and I would expect that to be used quite a bit. I guess the speed of the boats makes less of an upwind/downwind gradient analogous to the foiling catamarans.
 
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Aug 1, 2011
3,972
Catalina 270 255 Wabamun. Welcome to the marina
Gee, that foil sticking out of the deck is lifting the boat almost out of the water. :) Maybe they should make them cant above the waterline too.
 
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Oct 19, 2017
7,732
O'Day 19 Littleton, NH
Gee, that foil sticking out of the deck is lifting the boat almost out of the water. :) Maybe they should make them cant above the waterline too.
What a concept. Solid foil sail when on one tack, dagger board when on the other. :thumbup: That way, the wind foil being more to windward, there would be a shorter heeling force while still getting that foil up into the air. Of course all the righting force is gravity reliant not buoyancy reliant. Or is there a keel too?
Will (Dragonfly)
 
May 24, 2004
7,129
CC 30 South Florida
I think he is referring to a Stay Sail and not a Spinnaker. You all know what they say, "take it up and gain half a knot or take it down and gain half a knot". Some love them, others would not have them. They have limitations to optimal wind speeds and optimal points of sail. The most common set up is as a second headsail and can be used to store a light air or heavy weather headsail and used accordingly.
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
I think he is referring to a Stay Sail and not a Spinnaker.
Ah, I could see that. This is not done now because long ago NAs learned that the fastest practical sail combination for small boats was Bermudian sloop (single stayed headsail + main). Other combinations upwind (cutter) are old solutions created to solve problems that modern boats don't have.

Off the wind (as noted), different story.
 
Aug 2, 2010
502
J-Boat J/88 Cobourg
So, is it too simplistic to compare this to a sail trimmed fuller rather than flatter? More power can be generated but the boat may well be slower.
In addition to this question, is that chart True Wind Angle? Can they really point to low 30's true?
Thanks, Dan
 
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Oct 19, 2017
7,732
O'Day 19 Littleton, NH
I have been told that biplanes and triplanes began to lose lift efficiancy with the addition of each new wing. They generated more lift to a point but the upper wing took away from some of the lift of the lower. More modern biplanes have more offset because of this. The upper wing is much more forward.
- Will (Dragonfly)
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
In addition to this question, is that chart True Wind Angle? Can they really point to low 30's true?
Thanks, Dan
Yes.
Well, all the jibs (J0-J3) are staysails, and the codes (FRO and MHO) sure can, thats shown on the chart. The true flying sails (Gennakers) come into play (as the chart shows) at a wider wind angle.
 
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Feb 14, 2014
7,399
Hunter 430 Waveland, MS
Well that clears things right up.
Yep!
If I got caught using that graph on a school test....

CHEATING!!!

I use think I could compete in a race from just seamanship.:badbad:

Prediction: Auto pilot from the marina bar using an iPad app to race.
Jim....
 
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Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Yep!
If I got caught using that graph on a school test....

CHEATING!!!

I use think I could compete in a race from just seamanship.:badbad:

Prediction: Auto pilot from the marina bar using an iPad app to race.
Jim....
Oh please. Sailor have used charts and cheat sheets with angle and sail choices as long as I’ve been sailing. Nothing new here. Everyone does it. The fastest still win. Every race boat I know has its polar chart taped to the bulkhead.
 
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Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
That’s what Lance said.
Nope. Now you're implying it’s cheating, just hidden.

This behavior is clearly and explicitly allowed by the RRS.
 
Aug 2, 2010
502
J-Boat J/88 Cobourg
Interesting today to see the VOR 1300 UTC Daily Live – Saturday 18 November showing Turn The Tide and Scallywag running right together and on a parallel course. Scallywag carrying 3 head sails and TTOP with 2 (as far as I could see) and in one picture looked like only 1 head sail. Clearly a subtle, but important, distinction with quite little impact on speed given their proximity to each other. They referred to it as two boat testing!
 
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Oct 19, 2017
7,732
O'Day 19 Littleton, NH
Nope. Now you're implying it’s cheating, just hidden.
Sorry I can't remember his name but, there was a scientist (physicist) who turned his attention to chemistry and made Some significant contributions. When life long career chemists complained about him not putting the time in to actually learning chemistry, they pointed out that he didn't even know the periodic table of elements. His response was, something to the effect of, "why waste my time learning something that is right there hanging on the wall?"
- Will (Dragonfly)