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Best rope for main halyard

Printed From: Yachts and Yachting Online
Category: General
Forum Name: Repair & maintenance
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URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=5307
Printed Date: 20 Oct 20 at 5:33am
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Topic: Best rope for main halyard
Posted By: rs600
Subject: Best rope for main halyard
Date Posted: 15 Mar 09 at 4:53pm

   The time has come to replace the main halyard on my RS600. I did have excel racing 4mm, but this seemed to stretch with the massive cunningham loads on the 600 even after pre-stretching the halyard. Does anyone know of any other ropes apart from a kevlar one which would do the job better. Is Maffioli - 4mm Evolution 78Race any good?

Thanks,



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Oliver   (RS600   982)



Replies:
Posted By: Paramedic
Date Posted: 15 Mar 09 at 6:40pm

Vectran maybe, but rather pricey!

Personally i'd go for the Kevlar or a 2:1 halyard if you're allowed one.



Posted By: Villan
Date Posted: 15 Mar 09 at 7:21pm
Wire and a rack?

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Posted By: Lukepiewalker
Date Posted: 15 Mar 09 at 7:56pm
Dyneema will always creep, this is particularly noticeable over longer runs such as a halyard.
Vectran is the answer, if you can afford it.
Or a masthead halyard lock.


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Posted By: craiggo
Date Posted: 15 Mar 09 at 8:49pm
Put up with the Kevlar !


Posted By: rs600
Date Posted: 15 Mar 09 at 8:51pm
Thanks,  when you say vectran do you mean something like excel V12, will this cleat in the cam cleat? With kevlar how often do you have to cut some of the top off?

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Oliver   (RS600   982)


Posted By: Ross
Date Posted: 15 Mar 09 at 9:18pm
Kevlar has a tendancy to snap without warning.

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Ross
If you can't carry it, don't sail it!


Posted By: Lukepiewalker
Date Posted: 15 Mar 09 at 9:24pm
Kevlar not keen on going round corners.
You can get vectran as a 'conventional' covered rope, ie

http://shop.pinbax.com/index.asp?selection=detailed&uid= 10723&itemtitle=Vectran%20(4mm%20Dia)


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Posted By: alstorer
Date Posted: 15 Mar 09 at 9:50pm
Could I recommend cheese wire? It seems to be what we've got for the main halyard on the new mast.

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Al


Posted By: MRJP BUZZ 585
Date Posted: 15 Mar 09 at 10:48pm
Originally posted by Lukepiewalker

Kevlar not keen on going round corners.
You can get vectran as a 'conventional' covered rope, ie

http://shop.pinbax.com/index.asp?selection=detailed&uid= 10723&itemtitle=Vectran%20(4mm%20Dia)


Seconded

Its what i use now and i find it brilliant lasts yonks and it shows before it snaps i have found


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Posted By: Smight at BBSC
Date Posted: 15 Mar 09 at 11:20pm
http://www.ldcracingsailboats.co.uk/index.asp?selection=detailed&uid=9742 - 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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RS600 988


Posted By: craiggo
Date 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.


Posted By: Medway Maniac
Date 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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Posted By: farc anal
Date Posted: 16 Mar 09 at 10:44am
.


Posted By: rs600
Date 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,



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Oliver   (RS600   982)


Posted By: craiggo
Date 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.


Posted By: farc anal
Date Posted: 17 Mar 09 at 10:32am

Very simplified.

 



Posted By: Medway Maniac
Date 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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Posted By: farc anal
Date 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



Posted By: craiggo
Date 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


Posted By: Medway Maniac
Date Posted: 17 Mar 09 at 1:22pm

How can I put this?

Farc anal, imagine you are an angel holding up the sail by its head. You are supporting only the loads in the sail, which as you say are induced by kicker, mainsheet & cunningham. This is the halyard lock situation. Mast locks do reduce compression (as well as stretch as you say)

Now, instead of holding the sail-head, you're holding a pulley which has a main halyard running from the sail head and back down to the ground. You will have to pull twice as hard as before as the sail now has a 2:1 purchase on you.

Reduce the halyard tension by putting a block on the sail head and dead-ending the halyard end at your hand, and the overall load on you will go down as there will be less total loading in the elements connecting you and the ground (sail + halyard).

I call a halyard 2:1 if I have to pull the halyard twice as fast as the sail goes up the mast. This is what most people mean, but it is a matter of definition, as you demonstrate.



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Posted By: farc anal
Date Posted: 17 Mar 09 at 1:37pm

Thank god Craiggo,  thought I was bashing my head on a wall there .

EDIT oops just read above ----   apparantly after reading the maniacs reply I am ,

 

Not to worry I'll leave the maniac alone with his Angels

 

think the rest of the world knows what we are on about .

 

 

 



Posted By: Medway Maniac
Date Posted: 17 Mar 09 at 1:39pm
Like flat earthers, you guys are entitlted to your views. Just be sure to let me know if you build any aeroplanes or bridges...

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Posted By: farc anal
Date Posted: 17 Mar 09 at 1:43pm

Hey buddy ,

 

we are the folks that build planes and bridges

 

enjoy the ride .



Posted By: Medway Maniac
Date Posted: 17 Mar 09 at 1:45pm

Heaven help us all.

For what it's worth, I'll probably use 4mm Excel Vectran on the 3k when the current Selden Kevlar runs out. Presently it's doing very nicely having an inch or so cut off the top before each Nationals!



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Posted By: farc anal
Date Posted: 17 Mar 09 at 1:50pm

Heaven ------   Angels

 

 

you having a divine moment ???

 



Posted By: Medway Maniac
Date Posted: 17 Mar 09 at 1:54pm
Apparently I'm turning religious in desperation. But this is getting too much like a banter thread - we need some more tech input, preferably from someone who designed the existing generation of bridges and planes.

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Posted By: Medway Maniac
Date Posted: 17 Mar 09 at 3:43pm

Alright guys, here's another exercise to free up your thinking.

If I put a multi-block at the top and bottom of the mast, and instead of cleating the halyard at the foot of the mast as usual, I ran the halyard betwen the multiblocks N times then cleated it. Do you think that might increase compression on the mast?

Now go back to our earlier examples and have another think. The mast lock means there need be substantially no tension in the run of halyard coming down the mast from the mast lock, remember...



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Posted By: craiggo
Date Posted: 17 Mar 09 at 5:12pm
Medway, sorry to go back to what I was saying before.

Your analogy that an angel is holding the head of the sail up, and then you provide a pulley is all very well and good when you assume that the other end of the line is terminated at a rigid and isolated point with no degrees of freedom.

In the real case of a halyard the other end is terminated on the mast tip, and usually on the same pivot/pin that the tail runs over, and therefore it is all tied into the system which has degrees of freedom and is not ideally constrained.
As such regardless of how many blocks you have at the top of the mast ultimatly the total compressive forces are being reacted by the mast and the rigging, they are not miracleously halved by a pulley.

The load transmitted between the bulkhead and the boom in the kicker arrangement is not reduced by the purchases, simply the effort needed to increase the force is reduced.



Posted By: craiggo
Date Posted: 17 Mar 09 at 5:21pm
Medway, referring now to your latest question, the overall compression in the mast would increase if you ran the halyard back up to a multiple purchase on the mast because you have reduced the amount off effort required to install tension in the halyard.

I can sort of see where you are going on this therefore I will provide my answer.

Having a halyard which runs down the length of the mast will lead to compressive force acting on the mast, when no other controls are applied, however this force will be small when compared to cunningham and kicker loads applied when sailing. Changing from a 1:1 to 2:1 halyard will not change the compression forces acting on the mast, as ultimately the fully tensioned halyard will run down the mast, and once the sail is fully up the mechanical advantage is all gone, you have the same force tension in the line as a 1:1.

Obviously the luff curve on many classes is cut to allow for a given amount of mast compression caused by halyard tension. To remove the static mast compression from the equation the sails can be shackled to the top of the mast or use a halyard lock.
But as said above the compressive loads will ultimately be driven by cunningham and kicker controls not halyard.

Aaarrgggg my head hurts.

Back to designing aircraft I suppose!


Posted By: Medway Maniac
Date Posted: 17 Mar 09 at 5:48pm

But with a 1:1 halyard, the tension in the halyard running down the mast is by definition the same as the tension in the bit of halyard tied to the sail-head (less any minimal losses due to friction in the pulley). You will therefore have 2xT compressing the mast at least between the mast-head pulley and the gooseneck area, assuming the cleat is at or below the gooseneck.

Now, move your cleat up to the masthead (to effectively provide a halyard lock) and there's only 1xT acting between the mast-head and gooseneck area, namely that efected by the sail (we're neglecting standing rigging loads etc. here, obviously).

Put a 2:1 on the sail head and dead-end it at the mast-head and we'll have a lower tension in the halyard. Thus the compressive force will be that produced by the sail plus the lower tension in the 2:1'd halyard, hence lower compression than with a simple 1:1 halyard.



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Posted By: alstorer
Date Posted: 17 Mar 09 at 6:09pm
If a 2:1 didn't reduce compression compared to a 1:1, it also wouldn't make it any easier to pull the sail up- the force involved, after all, comes from the same source...

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Al


Posted By: craiggo
Date Posted: 18 Mar 09 at 8:21am
Yes & No.

Moving the halyard cleat up the mast reduces the exposed length of mast over which the force is acting. However multiple purchases will not reduce the overall force between the head of the sail and the block at the top of the mast, they simply divide the force up over all the runs out of the blocks. The overall force holding the sail up is still the same.
Once the blocks are all block to block you loose most, if not all of your mechanical advantage and the load on the tail of the halyard running down the mast will become almost the same as the force holding the sail up.

Your theory works absolutely fine assuming that you dont pull your main all the way up, however in doing this you expose much larger lengths of halyard to stretch.



Posted By: Medway Maniac
Date Posted: 18 Mar 09 at 9:45am

In practice you don't get the 2:1 halyard "block -to-block" (there are no blocks, of course), and there are exposed lengths of halyard between the mast-top pulley and the sail head (I've never seen otherwise), so the halyard  tension and compression remain reduced.

But I think you've now got the point.



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Posted By: Peaky
Date Posted: 18 Mar 09 at 9:58am

MM is right. 

A cat-style halyard lock does reduce mast compression, as well as eliminate halyard stretch/slip.

A 1:1 halyard has twice the compressive load of a halyard lock.

A 2:1 halyard has 1.5 times the compressive load of a halyard lock, or 0.75 times the compressive load of a 1:1 system.  Some of that gain will be lost due to system inefficiency, but there is still a gain.  However, you do end up with another 6m of rope to stow!

 



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Posted By: Jamesd
Date Posted: 18 Mar 09 at 11:11am

all this is confusing and im struggling to understand.

I mean Peaky, since when has a halyard been used in compression? rope would buckle almost immediately in compression. i know, you mean the mast has compressive forces.

with 100kN acting downwards on a mast from the sail you then have 50kN running down the mast in the halyard (if 2:1) therefore to resist the force the deck must produce a reaction, of 150kN, or the sail and mast will come out the bottom of the boat. the mast acts as a compressive member. thats all very well and good.

but what about the 50kN acting downwards at the dead end of the knot at the top of the mast, that brings the total downward force to 200kN thus the compression in the mast must be 200kN which is the same as a 1:1. the 2:1 will be easier to pull up and would require less of a reaction to hold it up there (think of a mainsheet and the difference of 1:1 and multiple purchases), but mast compression does not change.

locking the sail at the top of the mast reduces the compression as you can neglect the halyard loads acting downwards and therefore a smaller reaction is needed.

I think thats all right, my head is spinning to be honest.

Lol ive just confused myself even more.

in reality though, though the compression forces acting down do not run down the centre of the mast. they are offset (the sail at the top) causing a moment and initiating a buckle in the mast and thus the trailing edge of the mast carries compressive load and the front edge will be under tension.

plus there are many many more factors to think of, such as the fact the force on the sail is a vector not just a parrallel force



Posted By: Medway Maniac
Date Posted: 18 Mar 09 at 11:39am
Originally posted by Jamesd

all this is confusing and im struggling to understand.

I mean Peaky, since when has a halyard been used in compression? rope would buckle almost immediately in compression. i know, you mean the mast has compressive forces. Yes, it's the mast in compression, under load from the halyard/sail, not the halyard; that's what I understand Peaky to be saying.

with 100kN acting downwards on a mast from the sail you then have 50kN running down the mast in the halyard (if 2:1) therefore to resist the force the deck must produce a reaction, of 150kN, or the sail and mast will come out the bottom of the boat. the mast acts as a compressive member. thats all very well and good. Yes, except unless you run your halyard to the deck rather than to a cleat on the mast, all the main halyard loads are internalised in the mast. The mast foot/deck is oblivious to the halyard set-up, and feels only the weight of the mast, sail etc and the standing rigging, jib halyard etc. loads.

but what about the 50kN acting downwards at the dead end of the knot at the top of the mast, that brings the total downward force to 200kN thus the compression in the mast must be 200kN which is the same as a 1:1. the 2:1 will be easier to pull up and would require less of a reaction to hold it up there (think of a mainsheet and the difference of 1:1 and multiple purchases), but mast compression does not change. The 50N in the two parts of the 2:1 halyard connected to the sail head are merely transferring the sail load to the mast head - they are how the 100N from the sail get to load the mast at all - what the mast-head experiences is the pull of those two runs of halyard, plus of that going down the mast to the cleat, all loaded to 50N, thus the compressive force is 150N

locking the sail at the top of the mast reduces the compression as you can neglect the halyard loads acting downwards and therefore a smaller reaction is needed. Yes

I think thats all right, my head is spinning to be honest.

Lol ive just confused myself even more.

in reality though, though the compression forces acting down do not run down the centre of the mast. they are offset (the sail at the top) causing a moment and initiating a buckle in the mast and thus the trailing edge of the mast carries compressive load and the front edge will be under tension. You're right, but we've simplified it for the sake of discussion - by and large our conclusions are valid

plus there are many many more factors to think of, such as the fact the force on the sail is a vector not just a parrallel force Again, you're right, but it's a relatively small effect on compression that doesn't invalidate the simplified argument, but does indeed induce bend and very significant effects.



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Posted By: Peaky
Date Posted: 18 Mar 09 at 12:34pm

Quite so.

I have drawn a picture - sorry, I'm no artist!

On the left is a standard 1:1 mast.  Centre is a halyard lock.  Right of picture is a 2:1 set up.  Rather than drawing the masts I have assumed the head of the sail is suspended from the ceiling, just for clarity.  So the tensions shown of 2000N, 1000N and 1500N are in fact compression forces own the mast.

 



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Posted By: JohnW
Date Posted: 18 Mar 09 at 1:06pm
deleted - my head hurts


Posted By: Peaky
Date Posted: 18 Mar 09 at 1:51pm

Deleted reply to JohnW



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Posted By: Medway Maniac
Date Posted: 18 Mar 09 at 1:59pm

At least we're in total agreement, Peaky!

For 'floor' there, I guess you could substitute cleat?

Your 'ceiling' was my 'angel' in my earlier explanation. In each case it's the compression loading on the mast, as you say.



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Posted By: Peaky
Date Posted: 18 Mar 09 at 2:08pm

Absolutely right MM.  Angels sound much more poetic than celinings, but I couldn't draw an angel!



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Posted By: craiggo
Date Posted: 18 Mar 09 at 5:09pm
Sorry guys, but I still stand by the fact that if the sail is fully at the top of the mast you have lost your mechanical advantage and therefore the compressive load generated by the halyard is the same irrespective of whether you used a 2:1 to help pull the sail up or not.

I do however agree with the difference between these approaches and that of a mast top halyard lock.

The other thing to remember is that your compressive loads is not constrained as you have shown, as in effect the top of the mast can be considered to be spring jointed and not solidly contrained.


Posted By: Peaky
Date Posted: 18 Mar 09 at 8:17pm

Hi Craiggo,

As you obviously know, the mechanical advantage you get depends on the angle the ropes leave the pulley at.  Anything less than 180 degrees will reduce the 2:1 to something less, but there will still be some advantage.

And your right, the mast tip is able to move, so that it is not fully constrained.  But again, most of the advantage will still be there.

Glad you agree on the mast top halyard lock!  Much easier with a rotating mast of course - another reason to sail a NS14!  Where you down at Chew for the RS Open last weekend?



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Posted By: craiggo
Date Posted: 18 Mar 09 at 9:10pm
No I was supposed to be at the 700 open at Chew but I developed severe man flu towards the end of last week. I then suffered an allergic reaction to the man flu and developed urticaria, so a visit to the docs on Thursday provided me with some anti-hystamine and an appointment for a blood test.

I figured that sailin for a whole weekend could lay me low for a few days or even a week and I knew that this week was going to be a busy one at work so opted out.

I have to say the turnout sounded pretty disappointing, only 8 boats. Can only assume it was down to the poor forecast ie. Howling on Saturday and nothing on Sunday.

You ought to bring the NS14 to Thornbury Regatta on the last weekend in May, and get Chewy along as well. Hopefully the Cherub crowd will be along so could be a sociable weekend.

Paul


Posted By: Ross
Date Posted: 19 Mar 09 at 1:33am
Real boats don't use main halyards.

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Posted By: BBSCFaithfull
Date Posted: 19 Mar 09 at 12:15pm
Exactly ross 

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Posted By: Medway Maniac
Date Posted: 19 Mar 09 at 12:17pm

Originally posted by Ross

Real boats don't use main halyards.

You can explain that to the next RIB driver who rescues you



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Posted By: Peaky
Date Posted: 19 Mar 09 at 12:25pm

Originally posted by Ross

Real boats don't use main halyards.

You mean a Laser, right?



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Posted By: Andymac
Date Posted: 19 Mar 09 at 12:43pm
Originally posted by Peaky

Originally posted by Ross

Real boats don't use main halyards.

You mean a Laser, right?

Touche!  



Posted By: Peaky
Date Posted: 19 Mar 09 at 3:41pm

James, what is mast foot pressure a la windsurfers?
At any rate, you can't have it both ways - if the 2:1 system is pulled right to the top, there is virtually no extra length of halyard able to stretch/creep.  If the 2:1 isn't right at the top, then the angle between the ropes is going to be nearly 180 degrees, and therefore the 2:1 will work efficiently.  And what ever extra length of halyard there is, is in parallel, not series, so the stiffness is increased (hence less stretch).

Paul, sorry to say Chewy and me are one and the same - I lost my login details!  Tempted to do the Thornbury regatta though.



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Posted By: craiggo
Date Posted: 19 Mar 09 at 10:40pm
Aaahhh it all becomes clear now. The mysterious Peaky is in fact Chewy!

Jimbo when I was in the 600 fleet the main reason for going to 2:1 other than peer pressure was a belief that you could use the mechanical advantage to ensure that you had enough tension in the halyard to hold the head of the main at the top of the mast even with yehaaa cunningham applied. In my opinion it didnt work, as you regularly saw mainsail heads 6" below the mast tip even with 2:1. I firmly believe that this is down to the loss of mechanical advantage as you go block to block at the top. Once creep and stetch set in you actually end up with more rope to stretch and creep thanks to the 2:1 and so the sail appears to drop lower.

Best way to rig the 600 was always to make a crude 3:1 purchase with the tail at the bottom of the mast and pull on a load of tension. Even with extreme cunningham you get only a small drop in mainsail.



Posted By: Paramedic
Date Posted: 20 Mar 09 at 7:25am

A well known mast maker tested this out with weights. The results were astonishing in that the halyard running inside the mast operated under a mechanical disadvantage from kicker, cunningham and mainsheet loads so the the rope in the mast actually holds twice the load of the luff on the sail. If you think about how you rig up a cunningham this does make sense.

In some classes you want this to help de power, but in merlins with the flexible carbon spars the "bow and arrow" effect should cause a power drop just when you want it least, ie force 2 or 3. Halyard locks are becoming popular again, but I opted for a 2:1 halyard but haven't really sailed enough since to draw any conclusions. It looks good on paper though.



Posted By: BBSCFaithfull
Date Posted: 20 Mar 09 at 9:27pm
I have a release mechanism in my mast so no worried rib drivers

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Posted By: Medway Maniac
Date Posted: 20 Mar 09 at 11:05pm

Originally posted by BBSCFaithfull

I have a release mechanism in my mast so no worried rib drivers

Sounds interesting. How does that work?



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Posted By: BBSCFaithfull
Date Posted: 21 Mar 09 at 4:35pm
It comes from cst. Its basically a pin attached to a rope on the bottom of it.

Through which the head of the sail is attached

http://www.cstcomposites.com/images/Dinghy%20Mast%20head%20Q .Release.JPG

Alex


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Posted By: JimC
Date Posted: 21 Mar 09 at 5:43pm
Originally posted by Medway Maniac

You can explain that to the next RIB driver who rescues you

If I were on the safety boat I'd be delighted to see it. No wire halyards, no expensive ropes, just 5p worth of string I can unhook or cut with a knife and the sail comes down immediately with no snagging of rope in the cockpit.



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