Main halyard, knot or splice?

Robin

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OK I saved my pennies long and hard and finally bought a new Dyneema main halyard on special offer £175!!! We have a big mainsail a 50ft plus mast and the halyard goes back to the cockpit, so a long length heavily loaded and prone to stretch, hence our change from 12mm braid to 12mm Dyneema.

My question is how best to join the halyard to the headboard shackle? The existing halyard has a hard eye spliced in it, this results in a fairly long join which limits how high it can be hoisted before the splice gets into the masthead sheave, we normally do final tensioning at the bottom via a cunningham eye. I recall some years back a rigger showing me a knot like an angler's half blood knot which he said was as strong and could be made direct to the shackle, a much shorter and compact join which would allow several inches more halyard hoist. The rigger who supplied our new Dyneema halyard however said a splice was better and he has provided one end with a soft spliced in eye that is cow hitched to the shackle.

What does the panel think please? Strength is not really an issue, we could have swapped our 12mm halyard for a 10mm in Dyneema and still had a much greater break resistance, but it might not hold as well in the clutches.

Robin
 

john_morris_uk

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Perhaps its a bit late now for your new halyard, but I have stitched an extra cover on the dyneema where it goes through the clutch before now. Its a trick that some race boats use. The clutch tends to chew the cover up sometimes, so an extra layer not only gives improved grip, but can act as a 'sacrificial cover' for replacement when it wears out. It needs to be through stitched for its whole length though.

Ref the knot - its shown in a few knot books.... Perhaps someone can hav a go a describing it?

Are you sure the new splice will jamb - he might have made it a bit slimmer than the old one.
 

Robin

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John

[ QUOTE ]
Perhaps its a bit late now for your new halyard, but I have stitched an extra cover on the dyneema where it goes through the clutch before now. Its a trick that some race boats use. The clutch tends to chew the cover up sometimes, so an extra layer not only gives improved grip, but can act as a 'sacrificial cover' for replacement when it wears out. It needs to be through stitched for its whole length though

[/ QUOTE ]

Not too late yet because it is still in the lounge! Presumably the sacrificial bit would be made out of the outer from a regular braided line?

[ QUOTE ]
Ref the knot - its shown in a few knot books.... Perhaps someone can hav a go a describing it

[/ QUOTE ]

I know how to tie the half blood knot, I just wonder if that was actually the knot I was shown, Dyneema is stiffish stuff too so does it work with it?

The new splice is completely different, he has removed a long section of the outer cover and whipped this several times to the core, then the core has a soft eye spliced in it which threads up through the shackle and back over it to make the connection. So yes the effect is of a thinner and shorter link that woul enable another few inches of hoist. Maybe it is the bare core that I'm questioning as well, it just seems if a knot works it is both very simple AND easily done again if I needed to remove a bit that was chafed.

Robin
 

fireball

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The way most dinghies connect their halyards now is simple, allows changing the fixing point (and therefore cleating point) and allows the sail to be pulled right to the top:

Just fix a bobble onto the tail end of the halyard (the end that is going up the mast) and to attach it to the sail you just loop the line, poke it through the eye in the head and then poke the bobbled tail through that loop. The loop can then pull back through the eye safe in the knowledge that it won't come undone because the bobble won't pull through the eye.
I'll try and find a picture ...!!
 

Ships_Cat

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Our Spectra main halyard just has a small eye spliced in the end with no thimble. The D end of the shackle (a Wichard Keypin one) just sits in the eye (the genoa halyard is exactly the same).

There is no wear in the spliced eye after more than 8 years even though when the boat is berthed we take the main halyard to the end of the boom and pull it up tight to stop it rattling on the mast (and as you are aware, it gets a really good workout when so set, because of the frequent high winds here).

John
 

Stemar

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It may not be relevant, but I've seen a flogging sail pull a splice out of braided polyester. It was blowing a hoolie bang on the nose, with big seas, and none of us really wanted to go on deck to get it down...

It didn't take long, either.

Could you use an anchor hitch - a round turn & 2 (or more!) half hitches with the first half hitch through the round turn?
 

Robin

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Hi John

Yes that sounds how the rigger supplied ours except he suggested cow hitching it to the shackle (Wichard like yours) rather than just putting the shackle through the eye.

Robin
 

Robin

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Hi Duncan

I'm not sure it really was a half blood knot but it sure looked like it. I've got a very good knot book which shows the half blood knot but not anything else similar.

Why do you think it would pull out, desn't it tighten more under load or is the reason that it is stiff so doen't pull tight like it should?

Robin
 
A

angelsson

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Hi
I recently changed my main halyard with a top quality product, but had problems connecting to shackle.
I fellow boatie moored alongside helped and did the knot as previously decribed by other subscribers here, but soon as we put weight on it it undid-- up the mast again to rethread-- did same knot but this time tentioned it fastened to deck with a line to save it if it undid again, this time it didnt undo but certainly slipped to a very tight position, so we then stiched it through the not, and the bitter end to prevent further movement.
re-tested with lots of tension via the winch, much more than would getting a tight luff, and all as perfect.
This left room at masthead with sail fully up of about 6 inches.
Hope this helps,
Mike
 

JimMcMillan

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I used a half blood knot on my main (dyneema) for several seasons with no problems. Indeed the the biggest problem was loosening same from the shackle at the end of season.
 

Ships_Cat

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Hi Robin

Can't remember exactly how big the loop is in ours but is very small - too small to cow hitch or anything. Basically one pin end of the shackle will just fit through it - small enough that I have never had to take any particular care about the shackle falling out when the pin is unkeyed.

(Come to think of it our runners are done the same - they are Spectra and shackled to the block for the tackle that goes back to the winch).

So I wouldn't have thought there would be any worries about just having the shackle through the loop, cow hitched in your case as you say.

Regards

John
 

Robin

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Thanks one and all

It seems I have multiple choices! Since I already have a soft loop spliced one end that doesn't result in a thick section that will jam in the sheaves, I might try that first, if not I now know I can trim that off and go with a half blood knot or similar. That also allows for some chafe control later by trimming a bt off that will put a different section in the working part of the clutch.

Thanks for some useful suggestions.

Robin
 

alan_d

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The knot you are thinking about is the buntline hitch (you will find it on Google), but I don't know if it is any good in Dyneema.

Alan
 

salamicollie

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Not with most dyneema cored line e.g. Marlow D2 - the cover is polyster (or polyprop) and the construction is unbalanced i.e. the tension is taken by the core and the outer is for protection and handling. You can stripo the core off those bits that go through the clutches and are not exposed to chafe to save weight!

Different matter with other materials and constructions...
 

gandy

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Dinghy method is here :

http://www.wayfarerinternational.com/TJhalsheet.html

Suits frequent removal/reattachment of halyard, as in dinghy sail handling. Probably weakens the line more than a splice round a shackle, because the line is scrunched up in the stopper knot and around the cringle. For a small boat, the halyard is sized more for low stretch and handling, so loosing a bit of absolute strength doesn't matter.

So it may not suit larger craft.

Tony S
 
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