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Can I ask a genuine question?

 

Other than the "mylaska", everyone - both the manufacturers and the DIY options - seem to have moved away from moving parts (in the form of a block/sheave that would have been the case a few years back). To the eye, that seems to result in a smaller turning radius for the halyard and also potentially more friction/abrasion.

 

Clearly I have missed a chapter but the new lines are up to it?

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What is the size of the shackle pin Sam ?

 

shackle on prototype is Harken HR 6mm.

sorry made mistake on the SWL its actually Max Working load 1256.4kg, either way should be fine for a 8.5.....

http://www.harkenstore.com/uniface.urd/ ... MEB9Y989J8

http://www.convertunits.com/from/lbs/to/kg

the manufacturer will probably make 3 versions with different mwl and different prices from $79.99 to $149.99RRP

 

testing taking place on the new to NZ Formula28 cat

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Normal s/s pin of 10mm has SWL of 1520 kg.

If made by a reputable manufacturer. Some Chinese made can be as low as 700kg, knot all but some. If a mission critical use, use a good manufacturer. I didn't use the word 'brand' on purpose as that tells you squat these days.

 

1250kg but at a 2:1 safety margin. Using the way more common 4:1 margin used by most the SWL is 620kg. Gotta watch for that smoke and mirrors game a few are playing.

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Can I ask a genuine question?

 

Other than the "mylaska", everyone - both the manufacturers and the DIY options - seem to have moved away from moving parts (in the form of a block/sheave that would have been the case a few years back). To the eye, that seems to result in a smaller turning radius for the halyard and also potentially more friction/abrasion.

 

Clearly I have missed a chapter but the new lines are up to it?

 

blocks with this type of working loads are big, expensive and heavy. people with race boats would rather wear out the line a bit quicker than have a big heavy block up there.

you can also chop half a meter off the line where it wears every 6 months or so to stop it wearing out.

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Can I ask a genuine question?

 

Other than the "mylaska", everyone - both the manufacturers and the DIY options - seem to have moved away from moving parts (in the form of a block/sheave that would have been the case a few years back). To the eye, that seems to result in a smaller turning radius for the halyard and also potentially more friction/abrasion.

 

Clearly I have missed a chapter but the new lines are up to it?

 

The whole point of a 2:1 halyard is to reduce the compression down the mast from the main halyard.

It has the added benefit that as the main halyard is under less load the main stays up higher (closer to the top) and the halyard stretches less.

 

So in an ideal world what you want is an easy to pull up halyard and also once its up, a good amount of friction under load to reduce the compression on the mast, reduce stretch, keep sail at the top etc.

With these Tylaska styles once the main is right up, you can wail on the cunno and the main barely slips down from the very top.

It also reduces the load that the main halyard jammer is under (and in many cases the wear of the rope at the Jammer will be the biggest factor in needing to replace the halyard).

 

The design of the head shackle still needs to prevent excessive rope wear.

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To the eye, that seems to result in a smaller turning radius for the halyard and also potentially more friction/abrasion.Clearly I have missed a chapter but the new lines are up to it?

 

KM can probably answer this one better than I but it seems to me that the modern fibres being used for halyards on racing boats can probably a) cope with a slightly tighter radius and B) seem to be somewhat more slippery.

 

just an observation

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To the eye, that seems to result in a smaller turning radius for the halyard and also potentially more friction/abrasion.Clearly I have missed a chapter but the new lines are up to it?

 

KM can probably answer this one better than I but it seems to me that the modern fibres being used for halyards on racing boats can probably a) cope with a slightly tighter radius and B) seem to be somewhat more slippery.

 

just an observation

 

a) Nope they actually prefer a larger radius than pure polyester or nylon. But as most aren't using them anywhere near max loads a little tighter is usually OK. Too tight and you start losing strength, increasing wear and drag. Way too tight while moving under big loads it could generate enough heat to actually damage the rope. Dyneema/Spectra start to go bad at only 155 degrees odd. In an ideal world working on a radius of 8 times diameter and you're good as to go with minimal strength lose. 8 times isn't that hard so don't panic. Basically bigger is better.

 

B) Many are a shite load slipperier than Polyester or Nylon. Dyneema/Spectra is real slippery so do quite love the solid thimbles. Vectran knot so, it's knot as slippery, can be quite abrasive and more likely to 'saw' thru something than dyneema/spectra. To most average users the difference is minimal.

 

So when looking at load numbers you do have to keep in mind the application and how that will affect those. It would be very unusual for 99% of boats to be able to get within approx. 20% of the published breaking load without the rope on the boat breaking 1st. Many reasons for that which is a long story we won't go into here but it is something to bare in mind next shopping trip. Just mentioning that as we are seeing more people push their ropes into loads they really shouldn't be in. It's all good dropping a size or 2 with these grunty fibres but that does have it's downsides.

 

But as we all often check our halyards and lines we will notice that before it becomes dangerous.... won't we ;)

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What is the size of the shackle pin Sam ?

 

shackle on prototype is Harken HR 6mm.

sorry made mistake on the SWL its actually Max Working load 1256.4kg, either way should be fine for a 8.5.....

http://www.harkenstore.com/uniface.urd/ ... MEB9Y989J8

http://www.convertunits.com/from/lbs/to/kg

the manufacturer will probably make 3 versions with different mwl and different prices from $79.99 to $149.99RRP

 

testing taking place on the new to NZ Formula28 cat

 

static Main halyard load on an 8.5 cat is 684 kg

 

Shock load could be just a tad higher.

I would normally use a 6mm s/s pin on 460 kg or an HR pin on 800 kg.

 

In this case you should be quite ok but I wouldn't be too surprised if the pin bends a bit.

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