what to use for the tack line

SimonGH

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Westbrook CT
What happens if the sail drops in the water while the boat is moving / you broach? You would then have a halyard under tension that you wouldn't be able to release without cutting it. With these loose-luffed sails you really want the ability to unload any corner individually if things go wrong.
good point - so in my concept the 4:1 line would be in the clutch, so as long as that's free running you could simply release that and the halyard tension would unload.  The bitter end of the halyard would still be sufficiently long to allow you to drop the sail completely...

 

Snowden

Super Anarchist
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UK
good point - so in my concept the 4:1 line would be in the clutch, so as long as that's free running you could simply release that and the halyard tension would unload.  The bitter end of the halyard would still be sufficiently long to allow you to drop the sail completely...
I'm not sure I've understood how your "fixed point" would work but if you are happy that it can be dumped without gear or knots getting sucked into the mast halyard inlet then it sounds like a good idea.

 

SimonGH

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Westbrook CT
It would be hugely beneficial to understand the loads i'm trying to deal with.  Does anyone have a methodology / formula to calculate what the halyard tension is?

I obviously know sail size, and would assume a certain wind loading.  I guess I also need to calculate winch handle force to how much "static" tension I'm putting into the system.

The MWL of the furler system is bigger than the rest of the system.  I guess I could just base it on the weakest link in the chain, which is probably the clutch, turning block, or deck organizer.

 

SimonGH

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Westbrook CT
this is what i've figured out:

Riggers apprentice, a couple of other tools from Harken, all point towards a similar range of Halyard loads for the C-0 I have (~78m2) at around 2500 lbf (1100kg).

I assume that's "dynamic" loading based on the wind (I used 20kt).

The #40 winch gives a "power factor" of 40.2:1 for low gear.  So does that mean for every lb of force on the handle we get 40 Lbf on the line?

I'm trying to figure out the "static" tension.  That 40:1 seems a lot, since that means if you push with 50 lbs of force, you generate 2000 lbs?  Yet the WLL is around 1750lbs.  That doesn't seem correct.

 

Reference

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324
137
For the price/performance, 3/8" Samson Warspeed II is hard to beat.  And if you strip the last 8' or so, it'll run through the 2:1 friction rings a lot easier.   

(Also need to match this with a low-stretch halyard -- I like Robeline 9mm (really 9.5mm) Coppa 5000)

 

SSolo

Member
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England
on the Open50 we have 1:1 (asymmentric) 2:1 (code 0) and 3:1 (free luff J1)  tack lines that run through a fwd ZS jammer, then back to a 2nd ZS next to cockpit, we use the fwd ZS if shorthanded

mast is KZ and Karver Halyard locks so all luff tension is via tack lines

all are 14mm dyneema with a high friction covers (Southern Ropes)

 

SimonGH

Member
432
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Westbrook CT
So my concept works nicely (as I would have expected, it's not complicated).

I built a 4:1 tackle with two high strength double climbing pulleys and 12mm Viper line.  

I shackled one set of double pulleys to the mast base (where the turning blocks typically shackle), and the second set to a butterfly loop in the halyard.

Then I ran the viper line back through the turning block, organizer, cleat, and used the winch to tension.  

Physics cooperated and the tension on the winch was 25% of what was needed to properly tension the halyard.

So the only issue is what Snowden mentioned - the butterfly loop and shackle would stop the halyard from running free if you needed to drop the sail quickly.

I think the longer term solution is putting a constrictor clutch on the mast - if I can make it fit and mount it securely, the benefit of the constrictor clutch is that the line that is used to release the load can be extended, so you could route the release back to the cockpit.  

My plan would then be to tension with the 4:1, lock it in with the constrictor clutch, and then remove the 4:1 completely, leaving the halyard fixed by the clutch and the clutch release line run back through to the cockpit...

 

Parma

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PArma, is that a retractable bowsprit? Yes

How have you set up the Bobstay? The bobstay runs through a low friction ring , then passes through hole in the knuckle and is dead ended at both the knuckle hole and end of the sprit. There is a long bungee attached around the friction ring and then to the 3rd  back from the pulpit which keeps the bobstay from flapping around & out of the water when not in use.

Is it a Bene 34.7/R10 by any chance? If so, what size Zero did you go for? Yes. Biggest that would fit on the Colligo continuous furler using the MH spin halyards

Cheers!

 

Parma

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our current operation is to hoist the code on the halyard until it's made, then use the 2:1 to get the right tension on the luff. 
Same here. It works, just have to remember to tighten it a bit before we begin furling.

 

Parma

Super Anarchist
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 And if you strip the last 8' or so, it'll run through the 2:1 friction rings a lot easier.   
I ditched the friction rings in favor of an actual block because trying to bend a super heavily loaded line first around a 115 degree turn and around a full 180 degree turn through friction rings was difficult.

 

nauticalmonkey

New member
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0
USA
Advanced tech cores take care to flatten low-level load, which is why a decent clutch is essential.

A dyneema/poly blend will give you improved holding distinctive in an older clutch but you will addition stretch.

I don't think sta-set is a suitable halyard or tack line material for a code sail. It's too stretchy, and is dependent on the cover and the core so if the cover chafes at all you've lost a batch of posture. I cognizance the aforesaid about sta-set x. you want thing core-dependent like viper or endura-braid or warpspeed or something else that has a dyneema (or related) core,

 

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