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Dinghy main halyard


cep32

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I'm sick if having to lay the Javelin on it's side to put the sails on so am wanting to put a main halyard on the mast and a block for the forstay. For the masthead fitting I'm a bit lost. The Jav guys can't help as they don't use them. The only things I've seen are the mast head blocks made by seldon and c-tech which cost a fortune. Are there any cheaper ways of doing it? I was going to use a halyard block to keep the mast compression down.

 

For the forstay, there is the through-mast block for the spinnaker that is unused now that I run a gennaker. It is about 100mm above where the forstay connects to the mast now and about 50mm above where the sidestays connect to the mast. Could I use this instead of putting in a new block or will the mast bend be too unstable if it's above the sidestays?

 

Cheers,

Chris

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On the forestay use a 2.1 to reduce the load on the block plus compression on the mast use the existing forestay point as the dead end and then the old spin halyard block as your mast exit you will just need a grunt block to attached the FS to use vectran for the halayrd also.

 

mast halyard block just try and buy a sheave and make it fit or use a exit box

 

cheers blair

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I have a spare mast head halyard/lock fitting sitting in my box of bits looking for a home. It is (nicely) home made, plastic/stainless steel. Off a NS14 so would be ok for a Javelin. Wire halyard however currently. Probably easily modifiable with a hacksaw if you like cutting a wider slot in ss for a vectran halyard. No use to me.

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Thanks heaps for the offer and advice. I had half an hour to spare over the weekend so just drilled a hole in the mast and fitted a sheave. Just have to work out a way of stopping the halyard from slipping off the sheave now.

 

Thanks again,

Chris

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I checked the swage hook and have found that I can't change the angle that the forestay pulls at without creating an ugly point load in the mast. Can I get away with just riveting a saddle on the front of the mast and running the forestay off that? It would only be carrying half of the load as the halyard will go from the saddle to a block on the head of the jib and then to the old spinnaker halyard block further up the mast before going down to the base of the mast.

 

Given that it's only carrying half the load can I get away with using dynex dux instead of wire? I'm a little worried that if I use wire it will shred the spinnaker old spinnaker block. I have dynex on the prod stays but find that I need to sail in a good breeze 2-3 times and retighten before it doesn't stretch any more.

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Is the swage hook as you say a hook or what we calkl a T bar with a slotted hole as if it is a t bar you can get a t bar with a loop on the end.

 

I woul definately use either Dynema SK75 or Vectran if I was doing it I would use Vectran as it doesn;t creep and this is what you want this looped onto the T bar would be a real nice combo.

 

Cheers

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Thanks for the tips. I've put a mast hound on instead as I found one cheap and solves any hook issues. As for what rope to use, I was looking at using either Challenge Braid or Superbraid from Donaghys. The Challenge braid is vectran and comes in smaller diameters so I was looking at using aroun 4mm for a total load of 1400kg breaking load. I figure I should never get anywhere near that but would be interested if you thought it was not enough given I'll also be putting a few knots in it to hook in a halyard lock.

 

The Superbraid is Dyneema but only comes in sizes greater than 6mm.

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Use carbon rod. Damn close to the same price as wire yet a fraction of the weight.

 

One of the Javs up here is doing a set now. The 12's have some in use for over season with very good results. We have just done some load testing and it looks like it'll also be stronger than wire once the ends fittings are tuned a tad. Far better option than a SK75, even a heat-set one like Dux.

 

2.5mm carbon rod, $6.50 odd a meter inc GST. PBO ends. Simple to do.

Close as 1.4kg for the 2 sides which is less than the wire forstay alone, can't argue with that weight.

 

Having better access to super flash ropes than most of NZ, including stuff far superior to Dux in creep and loads, I'd still use the Rod. I really don't think a Dux like product will work that well on a Jav.

 

PM me if you'd like more details and I'll put you onto the Jav dude who is doing it now. He has time as his boat just got packed into a container heading the Aussie for the Inter-Doms.

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I'm guessing the carbon rod is solid (like stainless rod) so won't do too well running through the halyard block.

 

I've just looked up what load the 3mm SS wire rope (1X19) can take and it's around 760kg. I figure then that if I use 4mm Challenge Braid that is good for 700kg and it is at 2:1 then it's breaking strain is around 1.8 times that of the wire in the luff of the jib that has successfully handled the jandel up until now.

 

I figure I should be at a low enough percentage of the breaking load that there shouldn't be any creep.

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Oh you talking the halyard, I thought you were onto the shrouds sorry.

 

The forestay can be any old crap as that only holds the mast up until you get your headsail on, which takes the load while you are sailing. A few of the boats up here use a 2:1 SK75 3mm for the halyard. Were on 4 but recently moved to 3mm.

 

Uncovered but coated stuff, knot over braided like Super or Challange braids. Bigger loads on the uncovered obviously.

 

Correct Superbraid 6mm is the smallest from the Donaghys stable but Fineline make the same stuff down to 2mm. Donaghys Challange braid is made down to 3mm and Fineline does a 2mm version, no 3mm but a 4mm. No idea why.

 

Don't use Dux, going around a sheave will kill it's loads quick, heat-set SK's aren't fans of that sort of application. Use a unheat-set 75 like Dynex (the silver version), Ocean 12, Amsteel, Superround, all of which are unhest-set or have unheat-set versions.

 

Heat-set verse Unheat-set.

heat set a tad stronger

heat setting does reduce flex fatigue resistance by a LOT, an awful LOT.

heat set usually costs quite a bit more, which is strange as it should only be 'a little more'.

 

Heat set if in straight lines, none if going around corners a lot like a sheave for example. The strength difference at WLL is minimal. Did a job this arvo and at WLL the difference between the 2 on a 5mm is 235kg plays 270kg using a 10:1 safety margin. You could push that down to 6:1 or even 5:1 on a application like yours i.e. if something breaks it's unlikely anyone will die. You can go even less but that will just mean replacement will have to happen sooner.

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Question for KM:

 

Where do I go for this $6.50/m carbon rod?

I won't be replacing my stainless wire just yet as it is fairly new, but it would be good to know...

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Mr Ginge at C-Tec I believe. Also believe very limited supply at the moment but could be wrong so the next shipment may change the price.

 

Looks very interesting. That was for 2.5mm.

 

Did some load testing the other week and with some terminal tweaking it looks like loads will easily exceed that of the same size Dyform wire. Terminals being PBO or Zylon as it's being called more these days.

 

Just knot to sure what would happen to it if the crew got loose and smacked into it though. Having been said wayward crew on many occasions, I know we can hit it hard after one of those never seem to end Skipper cock-ups :) I'm sure with a few boats using it at the moment we'll soon know :)

 

But so far so good.

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I know that Brownie has a bit of rope on the side stays where the boom hits them to provide a bending point...

Perhaps with the knowledge that he might drop the rig, the skipper will be more careful?

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