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Carantoc said..

Skyron said..
Does anyone has-knows a way to suggest, for trimming the sail with a non Duotone extension?

+


www.surfsailaustralia.com.au/product/ezzy-stainless-tack-pulley

Ah yes I get this now , dam I've got the ezzy pulley blocks so would mean changing them for a new faster loop and go style extension.

I have a mixture of Superhero's from different model years.

The 22 & 23 model year sails have the pulley has the blue ring.

BUT for 25 model year, they now have 3 pulley block with a larger central pulley to align the rope when you are using the 2 pulley loop & go system (as shown). So everyone is a winner.....and they say windsurfing innovation is dead

Haha now I was told the two pulley is the only way to go
hmmm

So now people with newer style extensions and older extensions (or too stubborn to try something new) are all happy.

It's a bit more fiddly with newer extensions compared to the plastic separator but probably a compromise they made based on feedback from the second group with older extensions lol.

Or maybe just physics.

They physics don't matter for sails that don't require much force to downhaul like wave and freeride sails. The 16% difference in force won't be noticeable while you have to pull 16% more rope with 3 pulleys. This is the difference between pulling once or twice so give me 2 pulleys anytime.

16% (2/6th) is not even considering the increased friction as a result of the extra pulley so the practical difference is probably much smaller even. Based on my experience, the 2 pulley system feels more smooth so would potentially even require less force in reality.

I know people who use a hand winch to downhaul all their sails. Some use Duotone sails. They are all 65+ years. For them, the blue plastic would have been a PITA.

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ptsf1111 said..
The 16% difference in force won't be noticeable while you have to pull 16% more rope with 3 pulleys. This is the difference between pulling once or twice so give me 2 pulleys anytime.

That doesn't sound right to me, or perhaps I'm misunderstanding the writing.
The required force, neglecting friction, would be the following:
0 pulley in the sail: 1
1 pulley in the sail: 1/2=0.5
2 pulleys in the sail: 1/4=0.25
3 pulleys in the sail: 1/6=0.167 (approximately)

The required force when using 2 pulleys compared to 3, would thereby be: 0.25/0.167=1.5
So the required force when using 2 pulleys is 50% more than when using 3 pulleys.

With well lubricated pulleys, and large enough pulley wheels, I cannot see how friction could remove that advantage.

it's beginning to look a lot like Toe-in-anglefest

Can't wait for the Shimanotone Ultegrhero Di2 extension & outhaul system to make the sport more accessible

I don't have any of theses issues cause I use simmer

Thankyou Kris

the friction increase is very little.
otherwise cranes, engine lifting pulley blocks, boat rigging blah blah has all been wrong for thousands of years.
more pulleys - less force. The friction increase does not offset that much otherwise all the engineers are wrong.

yes you need to pull more rope thru but so? This was all about selling a new extension but disadvantages kids, women, people with a crook back etc who now suddenly need to buy a power XT that they didn't before.


physics - 2 pulleys = harder than 3. Simple.

anyone who doesn't believe can go get their 3pulley sail and downhaul by only threading thru 2 times. I bet you'd like 3 times better

Yeah it doesn't really translate like that. Let's use some examples for a wave sail (e.g. 60 kg of down force required) and a camber sail (e.g. 120 kg).

wave sail - 2 pulleys: requires 20 kg of down force, something that most people can easily do

wave sail - 3 pulleys: requires 15 kg of down force, only 5 kg less (8.3% of 60 kg)

There's not much benefit in having that extra pulley, especially when considering the extra rope length which means you'll have to pull two times when extension is over 20 cm.


camber sail - 2 pulleys: requires 40 kg of down force, pretty hard work

camber sail - 3 pulleys: requires 30 kg of down force, still a lot but most people would be able to do or use a tool to assist. The benefits of a third pulley becomes relevant when forces increase.

I think everyone who still believes there's a benefit in a third pulley for a wave sail, find me or someone with a modern sail on the beach and you can try it :D I'm sure you'd agree that the difference in pull force is negligible and as mentioned earlier, you mind find it feels more smooth due to less pulleys.

If you haven't tried, well you can't know.

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ptsf1111 said..
Yeah it doesn't really translate like that. Let's use some examples for a wave sail (e.g. 60 kg of down force required) and a camber sail (e.g. 120 kg).

wave sail - 2 pulleys: requires 20 kg of down force, something that most people can easily do

wave sail - 3 pulleys: requires 15 kg of down force, only 5 kg less (8.3% of 60 kg)

There's not much benefit in having that extra pulley, especially when considering the extra rope length which means you'll have to pull two times when extension is over 20 cm.


camber sail - 2 pulleys: requires 40 kg of down force, pretty hard work

camber sail - 3 pulleys: requires 30 kg of down force, still a lot but most people would be able to do or use a tool to assist. The benefits of a third pulley becomes relevant when forces increase.

I think everyone who still believes there's a benefit in a third pulley for a wave sail, find me or someone with a modern sail on the beach and you can try it :D I'm sure you'd agree that the difference in pull force is negligible and as mentioned earlier, you mind find it feels more smooth due to less pulleys.

If you haven't tried, well you can't know.

Yup

Anything on my 430 or below (which included up a 6.3 freek until I destroyed it), I use a cyclops extension with the two pulleys. Just feed the loop through, put that on the base retainer and pull with the hosing sheethed handle and it's done. Much much easier than fully threading 3 or 4 loop extensions.

Even with 4 loops on the big SDM 530 for the 9.0HGO, it still is a big pull compared to the 460rdm or 490sdm I have. But with those I use a clam cleat or if on the water my harness hook.

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SurferKris said..
That doesn't sound right to me, or perhaps I'm misunderstanding the writing.
The required force, neglecting friction, would be the following:
0 pulley in the sail: 1
1 pulley in the sail: 1/2=0.5
2 pulleys in the sail: 1/4=0.25
3 pulleys in the sail: 1/6=0.167 (approximately)

The required force when using 2 pulleys compared to 3, would thereby be: 0.25/0.167=1.5
So the required force when using 2 pulleys is 50% more than when using 3 pulleys.

With well lubricated pulleys, and large enough pulley wheels, I cannot see how friction could remove that advantage.

Nah , you just misunderstood the concept of these threads .
Commonsense and facts have no place here . What on earth were you thinking ?

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ptsf1111 said..
Yeah it doesn't really translate like that. Let's use some examples for a wave sail (e.g. 60 kg of down force required) and a camber sail (e.g. 120 kg).

wave sail - 2 pulleys: requires 20 kg of down force, something that most people can easily do

wave sail - 3 pulleys: requires 15 kg of down force, only 5 kg less (8.3% of 60 kg)

There's not much benefit in having that extra pulley, especially when considering the extra rope length which means you'll have to pull two times when extension is over 20 cm.


camber sail - 2 pulleys: requires 40 kg of down force, pretty hard work

camber sail - 3 pulleys: requires 30 kg of down force, still a lot but most people would be able to do or use a tool to assist. The benefits of a third pulley becomes relevant when forces increase.

I think everyone who still believes there's a benefit in a third pulley for a wave sail, find me or someone with a modern sail on the beach and you can try it :D I'm sure you'd agree that the difference in pull force is negligible and as mentioned earlier, you mind find it feels more smooth due to less pulleys.

If you haven't tried, well you can't know.

But those examples are mathematically wrong.

20kg using 3 pulleys would require 30kg when using 2 pulleys, there is no way around that.
That is a substantial difference even if they are both lower than what is required on race sail and 4 pulleys.

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SurferKris said.. But those examples are mathematically wrong.

20kg using 3 pulleys would require 30kg when using 2 pulleys, there is no way around that.
That is a substantial difference even if they are both lower than what is required on race sail and 4 pulleys.

No, it's 15kg for 3 pulleys, which is indeed 20kg for 2 pulleys.
But my wave sails are hard enough with 3 pulleys, I wouldn't want to try with only 2. admittedly they're about a decade old.

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ptsf1111 said..

If you haven't tried, well you can't know.

Don`t need to try a square wheel to know it`s going to be alot bumpier than a round wheel .
Kris has made it simple to understand , 3 pulley blocks have 50% more pulleys than a 2 block pulley system .
How could you possibly argue that is negligible ?

And Mark has made some great examples of the advantages of more pulleys , so go on , tell us , argue against that , tell us that those multi million dollar cranes have it all wrong , that they only need 2 pulleys because anymore is "negligible" .

Those cranes deal with tonnes of weight, not small loads like in our case.

What I know is based on real life experience using both 3 and 2 pulleys on wave sails. You don't have to agree but I do challenge you to try it out yourself and you will understand what I mean.

Edit: here is the reason: the extension acts as a third pulley. I didn't even realise it was there lol as you don't need to loop through it. Mystery solved Everyone happy now?

It might be fast but sorry Peiter it is simple proven physics that more pulleys makes it easier to pull

thus changing to 2 is a speed advantage only.
only that

so small folks might prefer 3.
might

thus, I smell a marketing rat. Them going back to 3 pulleys is suggestive of poor reaction from customers.

I'd like to chime in from an engineering point of view. The math says that the third wheel doesn't increase by a third , but goes better and increases the ratio by half again. So if your pulling 20 kg over one pulley your creating 40 kg. Do it over the second , it's 80 kg. Over that third wheel it increases to 160. That's not counting the other two pulleys at the base. We're talking lots of tension. Yes we lose lots , bending rope over a wheel that really doesn't spin easy or at all. That's where dyneema rope is better , cos it just slides when the wheels don't spin. Friction costs energy, but no where near what an added wheel produces. It doubles what the last wheel did. I did the maths once after downhauling an old 8.6 m race sail and as an educated guess , was pulling at least 80 kg trying to get that last cm. Probably more.I'm a big guy and veins on my forehead wear popping.My calculations got me close to 900 kg of stress my poor sail and mast had to put up with. That's calculating with a massive 30% off for friction. There is no way in hell I could have achieved that with two pulleys.
ps, if your wheels are ****ty and don't spin , more wheels will produce more friction. It could be a factor. A big factor. That's the only reason why dyneema rope is an easier pull. Not because it bends easier , probably opposite, but that it slides over wheels that don't spin. Those little wheels don't like to spin. I've given up trying to unjam them. I just use the third wheel , or better still a power EX.

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decrepit said..
No, it's 15kg for 3 pulleys, which is indeed 20kg for 2 pulleys.

Well, then lets check the maths for that, the load on the luff would then be:
15kg (for the 3 pulleys) x 6 lines = 90kg on the luff.
20kg (for the 2 pulleys) x 4 lines = 80kg on the luff.

Also I might pull twice but I rig once. So the saving of some 10-20sec while I am looking at the waves and making small talk really dun bother me. Loop n go is a notional advantage only. If the current forecast works out in the next few days, I'm going to try an only pull once if I can, just to see. But usually I pull twice and dun care about re-setting my downhaul puller tool thing and pulling for a second time.



I have an extension that works. It has no bits that might fail in the desert and can't be replaced or dodgied up simply. Its simple AF like they all have been for 40yrs and the pulleys line up with the sail part. Can borrow another one exactly like it with about 5mins notice. I have sails where the small blue thingy won't turn to crap in the sun (that a euro company didn't think of) and fall off.
I have an Ezzy sail pulley bit in the spares box so if I broke the standard one, I'd re-install in 30sec and be on the water again if I wanted.


I like easy, durable, fixable, same as all the others for consistency. Not "a little bit harder to pull, and BTW you need our extension too".
Oh and after a couple of years we go back again. Its marketing rubbish.


I'm out now but will reaffirm to the OP - nothin wrong dude your rope lines up good enough and if you get pulley to pulley contact, you're golden go sailing. Formuline might be better like others said.
I think I need to also go sailing

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ptsf1111 said..
Those cranes deal with tonnes of weight, not small loads like in our case.

What I know is based on real life experience using both 3 and 2 pulleys on wave sails. You don't have to agree but I do challenge you to try it out yourself and you will understand what I mean.

Edit: here is the reason: the extension acts as a third pulley. I didn't even realise it was there lol as you don't need to loop through it. Mystery solved Everyone happy now?

Not me , I`m never happy ... tired maybe ...
But I can`t stop thinking about the 3 pulley off the luff and 2 on the mast extension performance equation .
But still though , more pulleys the better .

There's been no wind.

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Imax1 said..
There's been no wind.

Yes, that's why people are arguing semantics over how many pulls they need to do. For me it's a couple and it's all over red rover. No need for more than that.

Oh wait, what are we discussing here? I think I might have my forums mixed up

Hehe, isn't a forum meant for discussions? I enjoyed it and there is no wind anyway. Let's keep the Seabreeze forums active over winter

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Mark _australia said..
I'm going to try an only pull once if I can, just to see. But usually I pull twice and dun care about re-setting my downhaul puller tool thing and pulling for a second time.

Yeah , we're off topic

Well I believe there is a mechanical device some blokes use, I'm happy with just the two pulls

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Mark _australia said..
Well I believe there is a mechanical device some blokes use, I'm happy with just the two pulls

I tried that only once. In the emergency ward they had to cut me free from my Power XT. They all laughed. Not so much laughing after they realised how much it cost to replace the rope.