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Best rope for main halyard

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Smight at BBSC View Drop Down
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Post Options Post Options   Quote Smight at BBSC Quote  Post ReplyReply Direct Link To This Post Posted: 15 Mar 09 at 11:20pm
This is what i'm using atm and it seems too do the job really well. Grips well and doesn't seem to stretch too much, it also looks pretty cool which is also a plus.

I usually chop off about and inch from where the halyard attaches to the mainsail every month, this seems to prevent the big bang until you run out of string 
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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 09 at 8:50am
Kevlar indeed doesnt like going around tight corners but as long as its loaded along its length it is incredibly strong and doesnt stretch. It makes Dyneema look like elastic!

I use a standard 1:1 halyard on my 700 as I did on the 600 and at the head I tie a figure of eight in the end of the halyard thread this through the head of the main and then tie a half hitch, the figure of eight stops the halfhitch from undoing itself and the only tight turn in the rope is the figure of eight. Every month ish I tie another figure of eight about 1.5cm further along the halyard and they last for ages.

On my 49er both main and job halyards were Herzog with loops in the end that fitted over a conventional halyard rack. I liked the simplicity of that arrangement, but getting hold of Herzog seems nie on impossible now. I'm guessing the nearest replacement is Holts own brand vectran, which I now use for my kicker cascade.

In both the 600 and 700 there has been a midfleet trend to go for 2:1 halyards but to me it doesnt make sense. Sure it makes pulling the sail up easier but once its at the top the mechanical advantage disappears, and if you cant quite get it all the way up then you effectively increase the amount of rope able to stretch. Not only does the halyard cost more (its longer) but you have a massive bundle of rope to stash away when sailing (Not so bad on the 700 now we have a halyard bag on the spinni sock.

Its also important to check the cleat on 600s as they tend to wear. Its not uncommon to see 6s 7s & 8s with two sets of cleats one above the other in order to reduce the likely hood of slip.
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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 09 at 10:04am

The total length of rope under load with 2:1 is hardly greater than with 1:1, and it's only carying half the load = half the stretch per unit length, so movement of the sail head due to stretch/creep is certainly reduced.

Also, compression loads on the mast caused by the halyard (substantially equal to the kicker+mainsheet loading on a 1:1 - the pulley at the masthead gives the sail loads a 2:1 effect) are also halved, meaning only approx 3/4 of the total compression loading, I guess, with a 1:1. Always assuming you don't want compression loading to bend the mast of course.

But you're right about the massive bundle of rope with 2:1, Craiggo - dropping the sail is a series of delays to untangle the halyard (if you're as sloppy as me). I've gone back to 1:1, but the loads on a 3k are hardly huge!

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Post Options Post Options   Quote farc anal Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 09 at 10:44am
.

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Post Options Post Options   Quote rs600 Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 09 at 9:46pm

Kevlar it shall be! Can you use the stopper ball way to attach the halyard to the sail or would this put to much bend on it.

Do you use the 4.5mm evoltion kevlar rope that LDC sell?

Thanks,

Oliver   (RS600   982)
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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 09 at 11:02pm
rs600,

You can use the stopper ball method of attaching the halyard but be careful, its difficult to see if you have any chafe leading to failure, and if the stopper ball isnt exactly straight or if the rope is slightly to tight a fit then it will crack the kevlar.

Anyway you'll have to tied a figure of eight or alternative in the rope to hold the stopper ball and the knot will be big enough to hold the halyard so save yourself the expense of the stopper ball!

Medway Maniac, I'm fully aware of all the arguments for 2:1 halyards including the theoretical loads cases, but they dont stack up. Its 11:00pm I've had a tough day including a trip to the Physio and my bain has packed up for the day so cant remember the reasons why its not all its cracked upto be, maybe I'll remember in the morning.
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Post Options Post Options   Quote farc anal Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 09 at 10:32am

Very simplified.

 



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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 09 at 12:02pm

Nice drawings, farc anal, but wrong figures.

With a simple 1:1, if the sail takes 100kg to hold up, there will be a further 100kg compression loading from the halyard running back down the mast unless you use a halyard lock (with all it's amusing whims).

With 2:1, you halve the load in the halyard, so that there's only an addtitional 50kg going back down the mast instead of 100kg.

So compression's 200kg for 1:1, 150kg for 2:1, or 100kg (and good luck reqd) for a halyard lock.

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Post Options Post Options   Quote farc anal Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 09 at 12:59pm

perhaps you are miss- interperating my simplified crappy sketch above .

put more less   simply , compression is product of down force generated on the mast tip , through combination of downhaul/cunningham tension , halyard tension , kicker,mainsheet , rigging , gravity ,  all acting together . to create a compression force .

once rig is set up doesn't matter how many purchase you use - you are only trying to create the SAME compression on the mast for set conditions , the loading on each individual purchase is less as you add purchase , but together add up to the same sought after compression .

 

off course you can increase compression by adding more purchase , but as  above you are only looking for a specific amount of compression at any time, as you say yourself adding 2:1 halves the load on halyard - actually most halyards are two to one think you mean three to one if you want to nit pick .

The max compression is when tack /cunnigham is pulled down as far as it will go with head as high as it can be .

 

Mast locks work not because they reduce compression- they don't  , but because they eliminate halyard stretch , no less load on mast at all . they can be a pain to use at times , but they  work ,thats why they are used in top competion where possible/allowed  , VOR , Americas cup , Finns , Etchells , humble cats ,Ok's etc etc

PS My Bad , figures are wrong above , the example of the 3:1 halyard on right should show 33.33333333333 kg pull on each leg giving the SAME 100 kgs Compression , in all cases compression generated by factors expressed above



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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 09 at 1:14pm
Farc Anal, has just provided my explanation that I couldnt think of last night, and I couldnt agree more with it.

Therefore 2:1 only benefit is the ease of pulling the main up. Once up there is no benefit although I find it can lead to loss of tension as the head moves along the line slightly. And when lowering it you end up in a tangle.

Oh and it costs a lot too
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