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You have a lot of catching up to do. A lot.
Bend has almost nothing to do with it. Bend is more important on a masthead rig where you use bend to increase headstay tension and flatten the main. With a frac rig you get headstay tension with runners or swept spreaders. And, if you sweep your spreaders 20 or more degrees you are not going to be bending the mast much.

This of the rig as one big foil. The jib is just the leading edge.
With a big main and a small headsail you no longer have to change headsails for optimal performance, theoretically anyway. There are heavy weight jibs and light weights jibs but the LP will remain about the same.

The photo you posted is misleading. Only one boat is flying a masthead foresail and this sail is a code zero. It is not their working headsail. It is a reaching sail. The other boats in the pic clearly show frac rigs. Look closely.

Tomorrow I race FRANCIS. Big, tall frac rig and I will make it sing.

In the end we know that one, articulated wing sail is the best sail for speed. The frac rig comes close to replicating the "one foil" approach than does the masthead rig.
 

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That guy has never sailed a modern frac rig. As I said in my post, with spreaders often swept to 30 degrees there is no mast bending to the degree it was some in old masthead IOR rigs.. You can bend the small top proportion if you want to but below the hounds the mast will be dead straight. I know becuase I design and sail these boats. I don't hypothesize or speculate. You can tune in a little pre-bend if you like. But once sailing there is little you can do with bending the mast. That doesn't always stop us from trying.

My Flying Tiger 7.5 meter.

My Flying Tiger 10 meter

ICON my all carbon 63' frac rigged lifting keel racer/cruiser
 

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The other huge variable that I forgot to mention is modern sail fabrics.

The modern racing matrix type sail does not stretch the way dacron stretches. The shape you want is there from the get go. You can adjust halyard tension, outhaul and cunningham to increase the draft of the sail but you can;t stretch a modern sail with mast bend the way you could with a dacron sail.

Take a look at a modern racing boat in light air. You will most probably see creases in the luff. Years ago this would have been unheard of. But with modern fabrics that one of the few ways you can play with draft.

Like so many "advancements" it takes a combination of factors to make it all work together.
 

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Stumble makes a very good point. The basic modern frac rig is a much bigger rig than the masthead rig of 20 years ago. A typical SA/D today could be 21.00 while a typical SA/D of 20 years back could be 16.5.

Tako:
I'll give you something to believe in SA (and I don't mean Sail area). Yesterday we raced FRANCIS with it's tall frac rig and got a First to finish and a First in Corrected Time win. We did this with a crew of four on a 63'er. Believe in that.
 

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Oma;
Boy, you are a snide little guy.

Time you educated yourself. All the info is out there. Lots has been presented here. We can't "make you" understand. It's not our lot to educate you. That's your job. You seem determined to stay in the dark when the light switch is right at hand.

Reach for the switch. Most of us did, years ago.
 

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I just can't do it. It would take a book to carefully go over all the varaiables here. I think it's a mistake to divide the the subject into two groups, i.e. masthead and fractional. There are so many sub-groups involved and that's without even mentioning hull shapoe differences in older masthead boats and movdern frac boats. I don't have the time to do it justice. Not sure I really know enough either.

I think there has been a lot of good material presented here and yes it has been clutterred with some less than accurate comments. But that's life and par.

With modern sail fabrics the entire picture has changed. The masthead rig of the old racer with its in line shrouds ansd super bendy stick was perfect with dacron sails as the rig could be shaped to change the draft characteristics of the sail relative to the conditions. With new, high tech sails, the shape you want is sown in from the start. You cannot stretch the sail to change the draft. If you need a fuller jib you can play with halyard tension and sheet lead but if you are seriously racing you'll put up a fuller jib. The LP may be the exact same as the flatter jib but the draft will be deeper. With the main you have halyard cunningham and outhaul to play with but with spreaders swept as much in some cases as 30 degrees you are not going to bend that "tripod" rig.

But if you go back 15 years you still had frac rigs that were effective but in those days mast bend was used and shrouds were in loine or almost in line. That's an entirely different situation.

Probably the biggest single factor to the success of the frac rig is we have come to learn that masive genoa overlap is not nearly as efective as additional luff length. Today it's all about leading edge.

Years ago the first of the Aphrodite 101's came to Seattle. About ten of theswe were ordered in Seattle. They came with a standard 100% jib. The class felt the boat would be underpowered in the light Seattle breezes. An overlapping genoa was built and two boats, one with 100% and one with genoa went out for two full days of testing in light air. The result was the 100% jib was just as fast as the boat with the genoa.

With squatty old CCA proportion rigs overlap was seen as a way to increase the SA/D. With the new frac rig the SA/D is much higher to begin with so there is little to gain from relatively inefficient overlap. Pragmatic advantage being you no longer need an "inventory" of genoas. I sail my frac rigged boat for 15 years with two jibs.

In summary (I hope) pretty much everything has changed. The question masthead or frac is multi dimensional and not just two dimensional geometry.

Racing FRANCIS last weekend we had a jib hal lead block failure resulting in a long beat in up to 30 knots AWS with an ugly looking, baggy jib. I was driving. We did the best we could with the jib and I tried to sail the boat mainly on the mainsail, our big sail, our driving sail. We did exceptionally well, walking away from the fleet upwind despite out jib hal handicap. This would not have happened with a masthead rig. Wewould have been crippled.

Sorry about being snotty. It's my vile nature.
 

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Thanks muchly Christian. I'm jammed today or I would have taken more time. Off to San Francisco tomorrow to give a talk at Saint Francis YC where I will have to act like an "expert". Getting ready today. Also doing my SAILING reviews today where I will once again have to convince myself that I am an "expert". No always easy to do. I'm still learning like everyone else.
 
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