Overkill?

I guess its not for me as i couldnt make it to the end of the video.

I wonder if the luderitz edition of the Mach sails are already cut this way?

In any case if you do that, what is the sail like on open water chop?

Someone i heard got their new Loft slalom sails altered for free after they arrived.

I think it was the same alteration but not his idea the sail makers idea.

Not sure if it made any difference but i will try and find out.

Good video. Windsurfing equipment has large tolerances; the cutouts not cut properly in the factory, defective battens, or not shaped to spec etc. Then you have large tolerances with masts. Error + error + error. This guy is a sail designer, and obviously knows what a race sail should look like. I interpret what he is doing as reworking the sail to make it perform like the manufacturer's concept sail. This guy's demonstration is another possible tuning method in the toolkit before pulling the sail up in buy/sell section and moving on.

I like what he said at 11:30 - if a sail is working for you, don't get rid of it. The latest model may not be better. Only get rid of old sail once the new sail performs better than the old sail.

He is a very competent sailor and he used to blow away the competition in Formula racing at several occasions, I'm sure he is onto something. ;)

Perhaps sailmakers prefer to error on the side of too loose leach, rather than risking a too tight leach (due to manufacturing margins).

Those diagonal wrinkles always bugged the heck out of me. And like he says, for all of us using 1000 grit or higher on our underwater foils, to see those big wrinkles just felt uncomfortable.

Is there also an implication that some sails open too much at the leech? I know that a couple of years ago, at least one pro used his foil sails on fin (at least in practice) and I'm wondering if that might be why.

Bloody 'ell. Now the cats out of the bag!!

3cm on one panel. Thats ridiculous. Were they designed that way? Are they designed for sailing in choppy water then he sails in, mainly in flatter water? Or designed for heavyweights, he looks 'normal' build.
Or just really bad workmanship on that sail? I wouldnt be happy after paying GBP1200 then another 100 on fixing them.

I thought seams were glued/taped before stitching, so more work than trimming a bit of monofilm off and stitching up again.

He also makes his owns fins. Of course he does. The sail does look nice on the water. He also uses seat harness. How unfashionable

This is like custom tuning the sail for a certain downhaul setting and a certain mast.

Ideally it needs to be done under load and not just static. The sail manufacturer should account for all of this though anyway

In 1982, John Bertrand and Australia II's sail maker made seam adjustments to both the forsail and mainsail after every race from photos taken during the race.

Tight leeches, the new in thing? We're going around in circles.
Would I be right thinking that 10 years ago, race sails had that much downhaul and they were so solid we needed a looser leech to get the sail to twist. Now they are made with less downhaul the same masts are effectively softer letting the top of the sail twist more. Is that why a tighter leech is becoming a thing?
Different but kind of the same, my NP V8 8.7 (luff 524), can use either a 490 or 520 mast. Two totally different feeling sails. Exactly the same mast just different sizes. The shorter mast is softer and twists much more, less power , feels lighter, better for high wind. The longer mast which is stiffer makes a tighter leech and is better for low wind.

Yep going around in circles, hopefully this time they will stick with smaller sails and tighter leeches as that's just a better way to do things.

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Ben1973 said..
Yep going around in circles, hopefully this time they will stick with smaller sails and tighter leeches as that's just a better way to do things.

Twist and loose leach the same thing?

Who remembers the sails that had a string down the leech that you could pull tight and wrap around the round thingy?

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Imax1 said..
Who remembers the sails that had a string down the leech that you could pull tight and wrap around the round thingy?

Yep..
Cripes that guy refers to the 73 wide isonic and 7.8m as his medium gear. That would be equivalent to formula gear gor me..
He makes the big sail look like a 6m the way he throws it around.

His sail is still twisting off., but it doesnt look like massive twist. Do Severne race sails suffer from flappy leeches? I dont see many of them where I sail.

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choco said..

Ben1973 said..
Yep going around in circles, hopefully this time they will stick with smaller sails and tighter leeches as that's just a better way to do things.

Twist and loose leach the same thing?

They absolutely DON't have to go together.

IMHO, it's a nice Dynamic twist of the upper leach that is ideal. Opens up to reduce power in the gusts and lower centre of effort. Closes up for better power and efficiency in the lulls.
Also allows a smaller sail with less drag and weight.

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PhilUK said..
His sail is still twisting off., but it doesnt look like massive twist. Do Severne race sails suffer from flappy leeches? I dont see many of them where I sail.

Previous generations did. M2 (7.8), had to play with set up a bit to get it setting correctly, there was a lot of pointless loose leech up there on the recommended settings. The new m5s ive found rig well on the recommended sail settings. Provided you don't over do the downhaul, the leech lays off the perfect amount. Just the odd flit from the leech on occasion.

Loki at the fastest sail craft, no floppy flappy leeches there and hardly any sort of twist

Why don't they just make the sails right in the first place?
It will good to see the end of the pointless flappy leech era.

The Code Red racing sails were less "floppy" but the Mach sails are much better to sail. :)

A tuneable leech would be fun to try, if it can be made lightweight enough.

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SurferKris said.

A tuneable leech would be fun to try, if it can be made lightweight enough.

I reckon the raceboard guys could tune it on the go.

Welcome to the toe-in thread v2

They're "floppy" for a reason (perhaps lay off or twist is a better way to put it, they shouldn't flap incessantly )Not everyone rides flat water, and unless you're on a foil or in flat water, a tighter leech is unstable for a windsurfer, because it moves the centre of pressure further up in the sail that we hook ourselves to. You hit a gust and a piece of chop simultaneously, that tight leech at the top suddenly turns into the business end of a lever and pulls you onto your toes quicksmart. you and your rig will be ultra fast for about 0.5 of a second, then you'll stop. It will also add more pressure at the mast base, which can make for a nose heavy board.


other craft that carry tighter leeches also have a different way of managing/altering sail shape. they attach strings to everything, so they can adjust on the fly. They also sheet the mainsail in and out constantly to keep the boat flying on the correct amount of heel, and deal with gusts. Believe it or not, that's actually less efficient than having a leech with twist, that allows us to not have to sheet in and out. They are actually starting to put square tops on sailboats now (actually, they started the trend quite a number of years ago) because they've come to realise that it's better to be able to let the leech twist off and let the sail breathe, rather than constrict it with a tight hooky leech.


Im sure Wojtek knows what he's doing if he's a sailmaker and quality sailor as well, but I'd be very cautious about taking a well functioning sail to a sailmaker for leech tightening. It could turn a good sail into a dog of a sail.

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Mark _australia said..
Welcome to the toe-in thread v2

Where's that one at?

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Subsonic said..

Mark _australia said..
Welcome to the toe-in thread v2

Where's that one at?

Never mind, found it

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sailquik said..

choco said..

Ben1973 said..
Yep going around in circles, hopefully this time they will stick with smaller sails and tighter leeches as that's just a better way to do things.

Twist and loose leach the same thing?

They absolutely DON't have to go together.

IMHO, it's a nice Dynamic twist of the upper leach that is ideal. Opens up to reduce power in the gusts and lower centre of effort. Closes up for better power and efficiency in the lulls.
Also allows a smaller sail with less drag and weight.

Didn't one of the sailmakers try for something like that once a few years back, with a a mast with an ultra flexi tip, and extreme luff curve at the top of the sail?

I think we need slowboat to post on here to de-bunk Wojtek and all his sail theories.....

Slow boat comes across like he knows his stuff - if only he could sail too i might fall for some of his theories

I prefer using a much smaller sail than i can hold as its so much lighter and faster in the gusts.

Not many i see now using 8.6m sails when years ago they were all the rage - a bit like wind foiling lol.

Even 7.8 and 7.0 usage seems to have dropped off somewhat.

5.6m is mostly about as big as i go now. Rigged with little downhaul and a stiff mast it planes almost as good as a 7m without feeling like i am holding up the QE2.

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Subsonic said..
Im sure Wojtek knows what he's doing if he's a sailmaker and quality sailor as well, but I'd be very cautious about taking a well functioning sail to a sailmaker for leech tightening. It could turn a good sail into a dog of a sail.

Yeah but, you wouldn't do this mod on a good sail. It would be something to try as a last resort on a disappointment that won't dial in; especially 2nd hand sails, where you have got nothing to loose.

When I watched Wojtek's video, to me, the theme was improved laminar wind flow, and improved even pressure on sail, which without that, he mentioned caused instability effects during gusts. Is the tighter leech a design goal ?, or an effect of the design goal ?

The goal isn't a tighter leech, as I have understood it, but to remove any diagonal wrinkles in the sail between the battens.

Following his recommendations regarding sail changes, one would need at least two sails in the same size. Modify one until it is the best sail, then try to improve the other one to be even better, and so on.