for 2 to 1 or not 2 to 1
Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Technique
Forum Discription: 'How to' section for dinghy questions and answers
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=8199
Printed Date: 08 Aug 25 at 12:25am
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Topic: for 2 to 1 or not 2 to 1
Posted By: Alto-Tim
Subject: for 2 to 1 or not 2 to 1
Date Posted: 23 Aug 11 at 7:07pm
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Question: On a 2 to one main halyard, what are the benefits? for 1- you have a 2 to one purchase. 2- it is easier to hoist the mainsail. 3- less compression force within the mast. against 1- a lot more rope in the boat. 2- considerably harder to drop as due to the length of the rope it gets tangled easier. 3- more expensive, plus more weight. don't knows 1) because there is only an inch of rope from the shackle, does this make it 2 to 1? 2) if you use good quality halyard the mainsail should not drop down the track?. 3) has anyone had problems with a two to one halyard breaking around the shackle area at the top of the mast?
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Replies:
Posted By: JimC
Date Posted: 23 Aug 11 at 7:42pm
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1) Even if there was 1mm of rope it would still be 2:1.
2) If the rope stretches it stretches. If you use decent rope it shouldn't drop anyway. 3) Any rope will go if you lead it over sharp edges or otherwise mistreat it. An issues with the 2:1 is that the end is rarely inspected. |
Posted By: olly_love
Date Posted: 23 Aug 11 at 7:43pm
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best thing to do is to make the rope thicker where it goes over the shackle, we have a removable tail to our halyard so less rope
------------- TWO FRANK-Hunter Impala |
Posted By: craiggo
Date Posted: 23 Aug 11 at 9:11pm
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I have never been sold on the idea. For one most sails are generally cut assuming a given mast bend profile. By reducing the compression force you reduce mast bend and may find the mainsail doesnt match the mast! The shackle at the top prevents you from ever getting the main fully up to the top of the mast. On boats eith measurement bands this isnt normally a problem, but on SMODs it generally pays to get the main right to the top.
Looking at the mechanical advantage, you only have 2:1 while the halyard turns through 180°. But when it is fully tensioned the angle is significantly reduced. Assuming you really tension the halyard, you'll probably end up with someone appraching 90° and hence much of the claimed advantage is lost. The extra halyard length is expensive and a pain to store in the boat, and makes dropping the main on a lee shore a bigger pain due to having to strighten out kinks and knots. I always use a 4mm kevlar halyard 1:1. The other option is to use a halyard lock at the top of the mast like the OKs or tip the boat a la Cherubs and tie it off at the top! |
Posted By: Paramedic
Date Posted: 23 Aug 11 at 9:30pm
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I found 2:1 halyard made a massive differance to the feel of the boat and the respose on the mast. On a carbon mast i think it's a must.
I now have a halyard lock. I didn't notice a huge differance from the 2:1 initially, but i am using more kicker than i ever have before, so something is going on!
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Posted By: timeintheboat
Date Posted: 23 Aug 11 at 10:48pm
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It seems the norm of RS400s - why is that?
------------- Like some other things - sailing is more enjoyable when you do it with someone else |
Posted By: Skiffman
Date Posted: 23 Aug 11 at 11:22pm
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Not to give all the secrets away but for a start rope shackles are a very good replacement for your normal shackles. The main will only come down due to the rope not being good enough, never a problem in the 49er. Best stuff is SK78 Max by Marlow, it will not creep or stretch under the loads we put on it in our 49er. As for the compression on the mast, I think this is down to the individual boats/masts. Yes it does compress the mast less but do you want less compression? We have the option of 1:1 or 2:1 in the 49er and most people use 2:1 and rope shackles. Just try both and see what you like but the main should always be at the top and never pull down whichever way you decide. ------------- 49er GBR5 http://www.teamfletcherandsign.co.uk - teamfletcherandsign.co.uk Team Fletcher and Sign campaign site |
Posted By: G.R.F.
Date Posted: 24 Aug 11 at 8:48am
Yep, mine went at the head of the Alto last week, I've just replaced it spent all saturday jiggling a bunch of bolts on the end of whipping twine which ended up with me having to abandon one of them at the bottom of the mast. It was crap halyard material anyway and nearly four years old, don't know what it is about boat builders and crap rope, it was stretchy, quite smooth so didn't cleat off properly, kept slipping, exactly the same stuff I got supplied with my RS500. It must be a price thing. I've replaced it with 4mm braided Marlowe stuff we use for downhauls, it cleats off better. No idea what you mean re 2.1 how else do other systems haul a sail up the mast from down below? ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: AlexM
Date Posted: 24 Aug 11 at 9:55am
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[/QUOTE] No idea what you mean re 2.1 how else do other systems haul a sail up the mast from down below? [/QUOTE]
One end on the halyard is fixed at the top of the mast then goes thro eye/shackle on the top of the sail and then goes down the mast------------- |
Posted By: alstorer
Date Posted: 24 Aug 11 at 1:01pm
2:1 halyard is seured to the top of the the mast. Runs through a shackle that attaches to the headboard, back up to the top of the mast and back down. Requires a halyard length approx three times the height of the mast.
(a 1:2 spinnaker halyard, as found on some boats, would blow your mind. Also, it'd REALLY f*** you off if a rope snapped) ------------- -_ Al |
Posted By: Alto-Tim
Date Posted: 24 Aug 11 at 10:58pm
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If you get less compression forces with a 2 to 1 compared with the 1-to-1,the issue of compression forces is due to the way you tighten the halyard before cleating it off. So if you use a wire and a rack there is less compression forces due to the halyard tension. Tension on the halyard at is applied by the kicker or the Cunningham. So if you have high halyard tension will this mean the top of the mast will respond more to gusts quicker because the top part of the mast is under tension?. So by not having high loads on your halyard must mean the mainsail will power up because the mast will be stiffer and not bend off so much in the gusts. All these questions come about looking for more power out of the rig
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Posted By: JimC
Date Posted: 25 Aug 11 at 12:34am
| Its not just the static tension on the halyard, if any, its the effect of the downhaul loads pulling down on the halyard. Given a stable mylar sail one of the the main effects of the downhaul is mast bend, so in theory I suppose you ought to get more mast bend for a given downhaul tension/amount pulled down the mast. |
Posted By: G.R.F.
Date Posted: 25 Aug 11 at 8:32am
Ah, think I get it now this is an Alto rig right? The Mk2 Sail? My thinking of 2-1 was the combination of a pulley at the head and the foot as mine has. The Alto is underpowered, at least the 2nd generations were imv, it also badly needs a mast head kite and a proper jib. The Solution would be for it to use a B14 rig, again imv. But the design criterion was for it to be used by skilled helms and semi to unskilled crews and it was originally going to be a hiker, which is why it performs so well in strong wind in capable hands. They really need to use the original main sail I'm still using, it wasn't much use on the original boat because they had a crap Gnav, but now it's got a Selden boom with the correct Gnav it works really well. Fantastic light wind performance yet depowers in stronger wind, maybe the designer might read this and take note, not that he ever takes much note of anything I blather on about or they wouldn't still have the silly cloth enclosed chute delivery system behind the forstay.
------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: Alto-Tim
Date Posted: 25 Aug 11 at 4:51pm
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Ah, think I get it now this is an Alto rig
right? The Mk2 Sail? ·
Yes you are right there, I think it's all in
the name.(Alto-tim) ·
We have a standard set of sails for the Alto
which works well in all wind conditions. My thinking of 2-1
was the combination of a pulley at the head and the foot as mine has. ·
????? The Alto is underpowered,
at least the 2nd generations were imv, it also badly needs a mast head kite and
a proper jib. ·
Underpowered??, We have
raced our Alto for a couple of years now. Depending what type of beer is for
sale, we are 30/31 stone and the boat goes well in all wind conditions. ·
Having sailed a 59er for
five years we found it underpowered., considering the 59er was built for heavy
crews. ·
And the mast head kite does not suit most of
the courses sailed at clubs and definitely not any river sailing especially
when the tide is out, nowhere to go deep,(and we broke two masts - no not in the mud (in a F3). The Solution would be for
it to use a B14 rig, again imv. ·
Don't know enough about the
B 14 to comment. But the design criterion
was for it to be used by skilled helms and semi to unskilled crews and it was
originally going to be a hiker, which is why it performs so well in strong wind
in capable hands. ·
I think you'll find that
the hiking idea was very soon discarded in the very early days of the
development. ·
We have had loads of people
test the Alto at different skill levels from novice to competent and found it a
well-balanced well-behaved racing dinghy. ·
I think any boat goes well
in strong winds as long as you can keep it up and pointed in the right
direction. They really need to use the
original main sail I'm still using, it wasn't much use on the original boat
because they had a crap Gnav, but now it's got a ·
I think the designer is
open to very sensible ideas and is not blinkered, we have worked with Mike for
two years. ·
I think the front foredeck
cover works well, covers up the
spinnaker, pleasing to the eye, practical plus economic . This discussion came about
over a couple of beers, about controlling masts bend and main creeping down. Although my name is Alto
Tim I hope coming on this forum doesn't mean to say I have to be talking about
the Alto. I do keep looking outside the box only to find the Alto is the best
well-behaved racing dinghy I've ever sailed. |
Posted By: RS400atC
Date Posted: 25 Aug 11 at 6:17pm
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In RS400's a 2:1 is favoured. It's normal to pre-tension the halyard as much as possible, so that the shackle stays right at the top of the mast, even with a fair amount of downhaul and leech tension. Until the leech and luff tensions exceed twice the preload, the head does not drop at all, even if the mast bend shortens the path the halyard takes inside the mast. In this case, a bit of stretch in the rope is actually good! Even using a kevlar 1:1 halyard, the sail drops significantly as the load comes on. The kevlar halyards tend to be a bit un reliable, 2:1's fail eventually too, due to chafe unless you cut a bit off every few months. It pays to be careful rounding off all sharp edges at the masthead, and make sure the shackle goes on the sail the right way round. If the shackle capsizes, the halyard running around the pin can undo it! |
Posted By: oldarn
Date Posted: 25 Aug 11 at 8:41pm
On your <original,AltO you have a Superspar mast with a normal 1 to1 system, and I assume a three year old main halliard. Whether kevlar (most likely) or other I guess it was chaffed. I would stick with a 1 to 1 8platt pre-strethed terrylene and put up with some stretch on the first few outings. Much cheaper and at least the cleat is holding the whole halliard and not just the outer surface. ------------- thefastexcitingrunningasymmetric |
Posted By: RS400atC
Date Posted: 25 Aug 11 at 10:09pm
That will stretch a few cm. May not matter in the Alto, except of course if your head is within a few cm of where you expect the boom to be! You could always use good old wire. The trouble with stretchy halyards is that pulling on the mainsheet or kicker effectively loses luff tension, like letting off the cunningham. So you pull on more cunningham to counter it, then you have too much, possibly even damage, when you dump the main or kicker at the windward mark. If money is tight or you want to use what's on hand, you can always splice a cheap tail into a mast-length of dyneema, this can even save a bit of weight. Also stretchy rope can chafe more, because it moves across the wear points more. |
Posted By: JimC
Date Posted: 28 Aug 11 at 6:25pm
| Conducted a little experiment today... My Canoe mast is a much lighter section than most, and although it is beefed up more than the standard tube I've still been suffering with the leech opening up too early no matter how much kicker I use. I've been mulling over beefing it up some more, but this morning I simply lashed the sail to the top of the mast to see what happened. I have to admit I am gobsmacked by how much difference it made: I estimate I could get my 15 stone of lard out another 8 inches out along the plank. So I suppose I am going to have to sit down and design a halyard lock of some description. |
Posted By: ham4sand
Date Posted: 28 Aug 11 at 10:52pm
 always nice when something discussed is showed to help!------------- John Hamilton cherub 2645 - cheese before bedtime cherub 3209 - anatidaephobia laser 176847 - kiss this [FORSALE] |
Posted By: Jack Sparrow
Date Posted: 28 Aug 11 at 11:06pm
Jim, have a look here: http://ukfarr37.blogspot.com/2011/06/details-details.html - Blog link this is what I have on my Farr 3.7 and it works a dream, with none of the safety issues of mast top lashing I / we used to do on the Cherubs. ------------- http://www.uk3-7class.org/index.html" rel="nofollow - Farr 3.7 Class Website https://www.facebook.com/groups/1092602470772759/" rel="nofollow - Farr 3.7 Building - Facebook Group |
Posted By: Contender 541
Date Posted: 29 Aug 11 at 11:12am
Jim - Have a chat with the 505 boys and girls - If I interpret your intention correctly, we have been doing this for years. We have a device that as you raise the main, there is a point during the lift that when reached, the halyard locks into place at the top of the mast - to release, you raise the main another inch which takes the halyard off the cam and alows the main to fall - no halyard loading on the mast then
------------- When you find a big kettle of crazy it's probably best not to stir it - Pointy Haired Boss Crew on 505 8780 |
Posted By: Lukepiewalker
Date Posted: 29 Aug 11 at 11:40am
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http://www.seldenmast.co.uk/fittings/content.asp?Category_ID=2
------------- Ex-Finn GBR533 "Pie Hard" Ex-National 12 3253 "Seawitch" Ex-National 12 2961 "Curved Air" Ex-Mirror 59096 "Voodoo Chile" |
Posted By: Jack Sparrow
Date Posted: 29 Aug 11 at 1:09pm
You can use a "v" cleat with an external main halyard with a knot in the halyard to place into the "v" cleat. You can also do the same by having a short wire strop using the tail of the strops copper ferrule as the knot that slides into the v cleat. I have used these before, and they are fine, a bit of a pain to find the v cleat with the knot. You also still have all the rope. I prefer the type now on my Farr 3.7 even though it requires rolling the boat to put the sail up. ------------- http://www.uk3-7class.org/index.html" rel="nofollow - Farr 3.7 Class Website https://www.facebook.com/groups/1092602470772759/" rel="nofollow - Farr 3.7 Building - Facebook Group |
Posted By: JimC
Date Posted: 29 Aug 11 at 1:58pm
| Yeah, that Selden device looks very neat, I checked it out, but it seems to me that I would need to remove far too much of my very skinny carbon mast tip to make it work... Similarly I don't want to use an external halyard. What I might do - at least as a temporary measure - is just put a bolt through the halyard sheave, add a hook each side and have a loop of string on the head of the main so hoist the main normally then roll the boat on her side on the water and just hook it up. The remote control piston would be neat for derigging, but combining it with a block for the halyard would be a fair bit of fabrication. I have a feeling I'm going to end up making a custom mast tip though. |
Posted By: Ruscoe
Date Posted: 30 Aug 11 at 12:41pm
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I had a selden Haliard lock on both my 505 Masts, great bit of kit when it worked, but when the ferell wears, its a bloody nightmare to get the main to stay up (it required a gentle, controlled be firm pull) something i could never bloody master. I would say that its going to be far to chunky for a canoe carbon mast, especially if yours is even skinnier Jib. I am sure a couple of cold winters nights in the garage and some carbon and epoxy could see you bash something together Jim, failing that i would think you are going to have to use a finn v cleat or RS300 cleat on the fron tof the mast method, which in itself is a pain to use when its howling! ------------- |