If so i'd appreciate some clues as to how you attach the loose end to the top of the mast. A photo would be good if possible

Thanks a lot!

Is the idea not that generally one has a single halyard going through the mast with a 2:1 system hooked onto its tail once it exits the mast as seen in the link?

Not in this case no. I want to reduce the compression through the mast itself.

Hi Chris, 3606 has 2:1 halyard. The top fixed end is spliced with small loop. You have the pin going through the head of mast with running block. What you'll need to do is use a slightly longer pin so you can attach a metal loop to it either side of the mast head. The loop will have to be bent to fit correctly, and that take the halyard. By metal loop I mean the thought of thing you screws blocks down to the hull, e.g. the spinny blocks. Sure they have a proper name but not sure what it is....

It has never jammed and works a treat.

I can send a pic if needed

Ross

Does the compression make that much difference Chris? The main advantage is there is less slip in the main sail coming down (though modern ropes seem to be better at not stretching).

Chris - I use what you are proposing.  I put a long bolt through the sheave and tie the halyard (3mm Excel racing)to the long bit sticking out of one side with a fisherman's bend. Put a washer on the outside so the rope can't fall off.  Has worked really well on my last two boats.
However beware - top tip: Bend a large flat shackle over the mast head and put the bolt through it.  This stops the halyard jumping off the sheave which it can do if you have to lower your sail at sea (to adjust top batten for example).  
Final tip - cleat the halyard round a horn cleat rather than a clam cleat - it won't slip.
Good luck!  John

Jacko has a neat mod to reduce compression and apparently it makes a lot of difference. (sorry jacko for letting your little secret out)

I've spoken to jacko about the mod but just want to try this first. Part of me thinks that compression through the mast is a good thing in certain circumstances because you can depower easily sooner. But I was also thinking that if you can take out (or in this case halve) the compression through the mast then you should get a power boost in the medium stuff, which you can then control if necessary by pulling on the cunningham which is a string i have not used since we deckstepped 3399 about 11 years ago!! 

Of course i could be thinking and talking utter rubbish so i'd like to try it out relatively cheaply first. Also you have the jib halyard operating at considerably higher load, abeit lower down, which will restrict any benefit.

Thanks for the replies, that was the only way I could see of doing it too. One further question, does this deck eye/shackley thing go over both sides of the mast or do you just bolt it onto the side?

Thanks.

Sorry John, just reread your post which looks like exactly what i had in mind!

Cheers

One final point - I found that the thin halyard pulling not quite in line knackered the rim of the plastic sheave.  So I changed it for a SS one.

Ta :)

Why not use a haliyard lock and reduce the compression totally?

Becasue to fit it is enormously more expensive than a relatively simple 2:1 and the lock may be no better becasue you can't lose the jib halyard compression, though that may be less significant being lower down.

Jacko has given me a guided tour of his super halyard lock. It is impressively well engineered.  It is however, as Chris says, expensive.  Also, those of us who have used halyard locks in other classes are nervous about not being able to release them when you need to. The 2:1 solution is, in my view, the best compromise.

Use a bolt and washer though Chris ; pins wear quickly and without the washer the halyard just jumps off.Both of these from personal experience :((

Please report back on the results, Chris.  In theory it should affect mast bend particularly above the hounds.  I doubt it will really make a lot of difference below as the tension of the main halyard (1:1) even with the cunningham pulled on tight is not going to be much above 100Kg (1000N approx for the engineers) as opposed to the rig tension at over 5x that, so taking 50kg of compression out of the mast may not really do a lot.  But it may helpfully stiffen the top section as there isn't any other compression there.

well, it's fitted so we'll see.

Manana has the same 2:1 as Ross describes but when the splice started wearing I just used a stop knot instead - self tightened by the loop and doesn't obstruct the running part of the halyard.

Are you going to go for the jib halyard a la White Whale too?  I had to get a sleeve put in the mast when I went carbon though so it could take the T recepticle...... :(

Urm, surely, as the mast is still seeing the entire load of the halyard, you are not reducing the compression on the mast itself. Having a 2:1 halyard will only reduce the load on the last tail of the rope, thus reducing the cleating load required and the turning block at the mast head. Of course, you will also double the length of the halyard in the first place.

Personally, never managed to find a non-stretch rope. We have a thin stainless wire onto a hook, then cleated to the kingpost under the deck.

No Andy, you are reducing the compression load in the mast as one end of the halyard is attached at the top of the mast so half the tension of the bolt rope of the main goes here not down the mast.

so why not 3-1?

You need an extra sheave at the masthead, weight and complexity, more to go wrong, for little overall gain, particularly as I doubt the 2:1 is actually going to make a lot of difference.

I've never believed in this compression reduction thing either - the load has to go somewhere....but I certainly cant spare the brain-power to comprehend it, so don't worry about explaining it!!!

If I remember my A level applied maths:- (big if)

The force required to keep the luff taught is normally (single sheave) the same as the force in the haliyard. I.e. the compressive load on top sheave is 2 x luff tension.

If you use a 2:1 pulley arrangement, then the luff tension is the same (by definition). The load on the top sheave is exactly the same (2 x luff tension) otherwise the sail will fall down - however, the haliyard has only 1:2 load.
The "missing" part of the load is taken by the fixing at the top of the mast (remember the 2:1 is anchored somewhere - from what I read by a bolt through the top sheave).
The compressive load on the mast is the same (ignoring friction):-
Case 1 = luff tension + haliyard tension

Case 2 = luff tension + haliyard tension + "fixed point" load.


Colin (3387)

The compressive load on the mast will always be the same as pointed out.

Andrew talks about the load on the bolt rope, well most of the time I hope you all sail with virtually none, I don't see cunningham pulled on hard except in F4++ or choppy water.

The biggest load comes from the kicker pulling the headboard down, through the tension leach.

The biggest benefit of this type of 2 to 1 is to
1. reduce the stretch by halving the load over the long bit
2. reducing to possibility of the cleat slipping, as the cleated load is halved (althoug this can be done at the bottom of the mast with a 2 to 1 hook into a splice, as per the standard winder setups)

Arguably, the halyard does not run straight down the middle of the mast, and hence creates a 'bow and arrow' effect making the mast bend more than you want it to. This means that whislt the compressive load is the same in total, you have an load which may become a problem due it its offset, the out of line load can be halved by a 2 to 1 (but not the total load). In reality, when you put a lot of kicker on, you want the mast to bend. I haven't heard of a mst breaking due to too much kicker - unless the lowers have been left off.

When you ease the kicker (and the cunningham if you have it on, and maybe the rig tension too) as you go 'off wind' the mast straightens and the load on the main halyard neraly completely disappears (you never get a problem unjamming the cleat when you come ashore and have let everything off do you?)

I have sailed with both systems (2 - 1 at the top and 2 - 1 at the bottom) and haven't noticed any difference except you have less halyard in the boat with the second system.

p.s. if you do go the 2-1 at the top - check the stopper knot every few races - the halyard wears through and if it breaks it tends to ruin the race

Whereas if you use a haylard lock at the top of the mast the compression is only 1 x luff tension.  

The reson I like 2 to 1 is that the tension in the rope is 1/2 and less likely to slip in the cleat at the bottom of the mast.

"if you use a haylard lock at the top of the mast compression is only 1 x luff tension"

But the haliyard lock has to push down on the mast - otherwise we could use skyhooks....

The overall compression in the mast can't change - what will change is how the force changes as he mast flexes.
With a lock, the force is fixed at the masthead. With a haliyard, then as the mast flexes, the Haliyard will change it's pull (slightly) because it's inside the mast cavity. 

I'd agree with the less slip in the cleat, but you can get that effect with a 2:1 (or whatever) on the tail after it leaves the mast.

Colin

I have thought about this especially before I posted but... With a haylard lock if I freeze everything and look at the loads then remove the main (virtually) then there is no additional downward pressure.  

Alternatively imagine the main suspended without a mast (bear with this one.. ).  Effectively the bolt rope round the sheaf at the top of the mast and down the halyard gives a two to one pull toward the ground  - the compression.  If I tie the sail to the sheaf (use a halyard lock) then pull down on the bolt rope I only pull once i.e. 1 x compression.

Actually the more I think about it that way of thinking works.  If i use a lock (tie it at the top of the mast) and pull on the bolt rope it is 1 pull.  If I put it round a block at the top of the mast and back to the ground and pull I get 2 to 1 so double the compression!

Tired of thinking now so of to watch the recorded rugby :-)

Still thinking.

The benefit of 2 to 1 at the top is that the tension in the rope is less so you can use thinner rope which gives less weight up top :-) very minor though I would think.  I would swap to 2 to 1 at the bottom if I could easily create a loop that could go up and down the mast without snagging.

As others suggest the fixing at the top tends to wear and that reminds me mine need inspection and possibly a replacement soon - which uses a lot on string!

Anyway since I use a Supaspar mast bend may not be my problem...

It is relatively easy to create a loop that won't snag in modern rope. Ideally you need a device called a fid, they come with instructions too. The difficult I have found is finding a fid the right size, you need quite small one for the core of 3.5 mm or 4 mm rope.

Basically you strip the cover back to expose the core, the you use the fid to loop the core back up the middle of the core, then pop it in and out a few times to lock it. The bring the cover down but not over the open loop. Then tightly whip the cover => you have a loop that is pretty much close to 3.5mm (assuming that was you original halyard) that will pop in an out of the mast no problem.

I am told you don't need a fib but you can do it with the inside of a biro, I havent tried but it would be about the right size.


Bit like below, but simpler and but dont put the cover on.

What bought all this on in the first place was borrowing a superspar when my chipstow broke and the boat feeling a lot less temperamental. The superspar had a 2:1 halyard.

Having tried it on the chipstow on sunday the sail does look differant, but i think i've been pulling it up too tight because you lose about 3mm of height with the shackle on the 2:1 so you can't overtension the luff like you can (and it seems i have been) with the pull up hook.

I still certain the theory stands, but how much differance it makes is debatable. On sunday we had an excellent 1st race and a less good result in the second, but this was at Shustoke and there are more variables to worry about than the tension in your main halyard!

I moved over to a 2 to 1 because I found with a single purchase I was having to set the halyard up really tight to avoid stretch and the consequent sail-slipping-down-the-mast syndrome.  Why do I mind a tight halyard?  Well I don't think the extra compression is very significant compared with that imposed by the stays but I have another concern.  Because we set our masts up with a little prebend the halyard inside the mast will usually be snug up against the rear side of the tube.  In conjunction with a lot of tension in the halyard this acts like an archer's bow and induces more bend in the mast. The extra bend induced can be very noticeable and under certain circumstances not what I wanted to see.  The 2 to 1 keeps the sail up with a much reduced tension (it's probably less than half because of the friction at the head of the sail) and allows the mast to be straightened up when required.
Dan

Chris,
Do you REALLY mean 3mm (or was it 3cm) of height loss - didn't think that would be really critical and how much stretch in the halyard would there be to take that up?

Doesn't the tension in the LUFF come from the cunningham?

Only if the head does not drop.

The point I was making is that if you pull the sail up the mast until it stops (as in the earlier post about pulling it up until the shackle hits the top) then any further pulling on the halyard will only tension the halyard more and will have no further effect on the luff, which should stay nice and wrinkly until you apply cunningham. This leads me to think that Chris's problem doesn't come from overhoisting his sail as the halyard really only controls the height of the sail (on a loose footed sail) and the luff tension comes from the cunningham. I just think he should look for the solution to his problem elsewhere.

It's about 3-5mm lower, i haven't measured it. Releasing a small amount of halyard tension has made a significant differance with some sails (older 90's vintage Hydes especially) i've used in the past in certain circumstances, and in my experience it's better to have the luff a bit loose than too tight. 

If you pull the sail too high you often get a crease from the tack up towards the outer edge of the top batten especially if you place the tack strap below the lowers and the tack is held down. If you release the halyard to clear it it takes very little movement to do so therefore, yes, i beleive that 3mm may be significant in certain conditions.

If anyone has a moment, lets see some photos taken along the mast, to show the shape change that comes from the 2:1 (jib or main halyard).

I was just wondering whether the ultimate loss of compression from the main halyard has had a race losing effect - I think Dave Winder had the boat on its side before one of the champs races tying the main up to the top of the mast after a halyard broke, did it vastly affect his finishing position and does anyone remember which race it was (I have a feeling it was the last day)

More and more classes, Skiffs especialy, are doing away with the main haliyard altogether.

I think any race loosing effect would be due to the stress of trying to sort it out!!

Believe it was the last race of the champs, about 20 minutes before the start as we had a look due to curiosity of why Dave and Pipa were swimming.

If so he then posted the best result of his week with a 7th after a 9th on the race before and 2 11th's earlier in the week

Thus proving haylard induced compression is an issue. 4 to 1 anyone

A couple of places doesn't really prove anything to be fair, 20th to 7th would be a bit more convincing.

I think the theory is correct though and will be interested to see what happens this year.

4:1 i don't think would have any advantage over a 2:1 becasue if the set up involved, 5 miles of main halyard and a awkward tackle on top of the mast. If you're going to go to that trouble you might as well go for the lock.

was said tongue in cheek :-P

Lidle are doing 16:1 hoists for under £4.00 this week.

That was last week they were on offer - £3.40 each - the rope is pretty terrible nylon and rips your hands and very springy  but the blocks are fine for the intended job.  I can see my Firefly up in the joists next winter!!