Dinghy development: RS600: stretchy halyard?

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RS600: stretchy halyard?

Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Dinghy development
Forum Discription: The latest moves in the dinghy market
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=11529
Printed Date: 12 Jul 25 at 11:09pm
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Topic: RS600: stretchy halyard?

Posted By: dohertpk
Subject: RS600: stretchy halyard?
Date Posted: 26 Jun 14 at 10:53pm

Hello hive mind,

I'd appreciate your advice once more. Whenever I pull the downhaul on my 600 (and I pull it on hard), my sail slips down from the top of the mast about 6 inches. Could this be due to a stretchy halyard, or am I rigging wrong? As always, many thanks for your generosity and patience.

Peter

Replies:

Posted By: Null
Date Posted: 26 Jun 14 at 11:15pm

Could be a number of things, what rope are you using? Secondly is the cleat slipping slightly? They don't last forever. Finally are you not meant to pretension the Halyard by pulling sail up then pulling loads of Cunningham on then release and pull sail up again? To take out the stretch? Could be wrong but seem to remember this from years ago when I borrowed one?

Posted By: craiggo
Date Posted: 26 Jun 14 at 11:21pm

Russ is correct, a certain amount of pre-tension is desirable on the 600.

I used to pull the halyard until the sail was fully up, then take the tail and tie a loop in it where it exited the mast. I would then take the loose end and run this around the boom bolt and back up through the loop I tied. You can then graunch the halyard up the last bit pre-tensioning the rig. This last little bit as well as inducing the right mast bend, also pulls the stretch out of the kicker as it should only just allow the sail fully up when fully released.

Posted By: dohertpk
Date Posted: 26 Jun 14 at 11:25pm

I don't think the cleat is slipping no. Embarrassingly, I don't know what rope I'm using (still relatively new to the sport). What kind of rope should I be using? The method you describe at the end of your post does ring a bell, but I think it's meant to be hard on the sail and I've spent 200 euro on sail repairs in the last 6 months so trying to avoid anything too onerous on the sail cloth. I'll have a look at that technique again though - I had thought it was optional and not a necessity.

Posted By: craiggo
Date Posted: 27 Jun 14 at 12:01am

I used to have a standard 1:1 kevlar halyard. Still run the same on my 700.

I never noticed any extra wear on the 600 main as a result of halyard tension. The only wear I suffered from was the usual batten ends on the boltrope.

Posted By: dohertpk
Date Posted: 27 Jun 14 at 12:26am

Yeh I'm having the batten ends fixed at the moment actually. If you wouldn't mind, could I ask you to explain the method of 'pre-tensioning' the halyard with the downhaul in a bit of detail? I've had a read of the 2002 rigging guide but the instructions as to how to raise the sail and use the downhaul with halyard aren't detailed enough for me.

Posted By: Rupert
Date Posted: 27 Jun 14 at 8:39am

All you have to do is pull the sail up, then put the downhaul on as tight as you can. Once you've let it off again, you'll find you can pull the halyard up more. Do this a couple more times until you are geting no more movement at the top of the mast.

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Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686

Posted By: iGRF
Date Posted: 27 Jun 14 at 9:00am

I've just tried to correct this very same problem, 1st off it was worn cleats, so I changed them, then it was diagnosed as stretchy halyard, so yesterday took myself off to the Chandlers via an hours traffic hold up and asked for their recommendation.

Dyneema core and its a£1 a metre came the reply, so 14 mtrs later and a lot of pfaffing around with fishing line and plumb weights (we'd already pulled the old one out by accident the race previously). Did it work? No, there was still a couple of inches, I'm hoping it was just new line 'stretching in' but am going to be gutted if it happens again on sunday.

The other thing we had problems with whilst I'm on, was spinnaker hoist going all curly then jamming in the block, we re roped that as well, but used some cheap stuff which seems to be ok so far, I've found that dyneema cored stuff to have more of a propensity for twisting than just plain 8 plaid, but would love to know the views of the hive mind.

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Posted By: tgruitt
Date Posted: 27 Jun 14 at 11:11am

Also, don't hoist the halyard with the rope through the cleat as it wears them out really really quickly.

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Needs to sail more...

Posted By: Neptune
Date Posted: 27 Jun 14 at 1:29pm

£1 a metre.....yeah that's going to stretch again. Something like Excel elite with the SK78 core should be more like it at nearly £3 a metre (4mm should do it).

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Musto Skiff and Solo sailor

Posted By: bristolmustoskiff
Date Posted: 27 Jun 14 at 2:54pm

you need the black rope with the kevlar in it 4mm last forever when you think you have pulled it up tie a loop in the halyard then tie the cunning ham to it and pull it tight that will take the stretch out of it

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live hard race harder

Posted By: Jack Sparrow
Date Posted: 27 Jun 14 at 5:27pm

One thing to check if your old halyard is Kevlar.

Kevlar doesn't like tight corners and has a habit of breaking at knots. You won't realise as the the kevlar core has broken inside the outer sleeve. You could be getting slip because you are actually only tensioning the sail with the outer sleeve of the rope which then stretches under load.

Dyneema on the other hand creeps and takes a little time to bed in depending on the variety. But yes the SK78 (Excel D12 Max78) or SK90 (Excel Elite 90) minimise this to the Max and would don't the Kevlar sleeve trick as they don't mind corners.

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Posted By: Paramedic
Date Posted: 27 Jun 14 at 9:17pm

Don't buy SK90 for dinghies it has no advantages over SK78 for our purposes and is more expensive.

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Posted By: NHRC
Date Posted: 29 Jun 14 at 10:58am

Paramedic you are completely wrong about SK90.

I have tried and tested it on a number of boats and it is the best product for no stretch applications.

For example when testing a Laser Vang first part of the cascade in SK78 the result after a 20 minute sail in a 15 kt breeze was 65mm stretch

With SK90 it was under 20mm

20mm would have been the splices bedding in.

What I would add to this thread is that to reduce stretch/creep

a). Use a good product, might not be cheap but it will last and wont fail.

b). Work out the load that the line will carry and multiply that by a safe working factor of 4:1 to counter dynamic loading. Buy a rope diameter that will carry that Safe Working Factor

c). Splice ropes wherever possible, knots cause failures, reduce the strength of the rope and degrade it massively

d). Dont run un covered ropes through cleats as you degrade them very quickly

e). Dont use high UV sensitive ropes (Vectran or Kevlar are most common), without checking and replacing them very very regularly.

Posted By: Paramedic
Date Posted: 29 Jun 14 at 9:13pm

Sorry but that doesn't bear out what the fibre manufacturers themselves claim, or what i've found on a variety of boats.

According to DSM (The fibre manufacturer who supplies Marlow and English Braids) SK90 is stronger than SK78, but has similar creep to SK75. So i don't know what was going on with your Laser kicker, but i have found that poor quality rope - even using SK78 - is a waste of dyneema. The fibre is only part of the equation, the lay of the rope and the pre-stretch process have much to do with it and cheap rope is, well, cheap.

Most dinghies will never need this extra strength, and we all want low stretch/creep.

If you want ultra low creep you want DM20 aka Dynastay - i've used this instead of Vectran on a number of boats and it's very, very good.

The rest is good advice tbf :)

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Posted By: NHRC
Date Posted: 29 Jun 14 at 11:39pm

I completely disagree with you. I am a rigger by trade and have been specing ropes for boats from oppies to the worlds largest super yachts.

Sk90 creeps a lot less. It is stronger.
I highly recommend it for all applications where you wish to have no creep in a line.

Dm20 is a good product for stays, shrouds and forestays.

Sk99 is the new product that we will be using for non creep lengths from now on.

All dyneema is produced by dsm.