single line reefing - big stresses

[dylanwinter]

I watched a sailor cranking his single line reefing down using a fairly big winch on the coachroof

It really did look like a lot of strain being put on the sails and blocks

there was a lot of friction involved

has anyone tried single line and then gone back to two lines because there seemed to be just too much stress involved?

or had everything go bang as a block pulled out?

is that a design problem - or inherent in the fact that you are trying to pull a sail in two directions at once?

never going to fit it to Katie L - but I might be able to go from three line reefing to two line reefing

but it did not look good to me and I wondered about getting a decent sail shape in the reefed main

yours

worried of Botolph Claydon

 

[prv]

Used it on charter boats and thought much the same as you.

Have separate tack and clew pendants on KS and would do the same if at all possible on boat.next.

Pete

 

[JimC]

I've had two British Hunter yachts with single line reefing. The first was a Horizon 23 on which the reefing lines just passed through eyelets in the luff and leach of the sail, with this there was a lot of friction as the OP states. My current Channel 31 has small nylon blocks attached to the sail instead of eyelets and there is a lot less friction and easier winching even though the sail is a lot bigger.

 

[dylanwinter]

are those

I've had two British Hunter yachts with single line reefing. The first was a Horizon 23 on which the reefing lines just passed through eyelets in the luff and leach of the sail, with this there was a lot of friction as the OP states. My current Channel 31 has small nylon blocks attached to the sail instead of eyelets and there is a lot less friction and easier winching even though the sail is a lot bigger.

are the blocks ones with bearings in them or just nylon bushes

I wondered if that was one reason why friction seems so high

I would guess that getting the geometry absolutely spot on is also pretty crucial

Dylan

 

[NUTMEG]

Got both...

Single line for first reef and two line for second.

Single line works a treat, just use halyard winch for final tensioning.

Have a bit about it on my blog, with a diagram and piccys, there's flash for you!

 

[actionoptics]

single line reefing

We have had single line reefing back to the cockpit in our LM 30 for over 7 years without problem but it is essential to keep all of the pulleys running freely. Getting the correct angles has taken time and last year we got the sail maker to add pulleys instead of using the cringles and they have made reefing very easy although we do have to use a small winch. The sail even with the second reef in, does still set well but then it was made by Sanders of Lymington with the express pupose of being able to be reefed with single lines.

 

[lw395]

The load on the reefing lines is much the same as in normal slab reefing.
The real load happens when the sail fills, not while you are reefing.

But some single line systems are terrible. If any pulleys in the boom twist, friction is immense.

Good single line systems can work really well though.

 

[vyv_cox]

With a balance block system the loads on the pennants can be high, the route of the aft one in particular is complex, with several turning blocks. I don't think the loads on the sail are particularly high though. I replaced my 12 mm polyester lines with 8 mm Dyneema, which copes well.

 

[dylanwinter]

Dybneema - free running

With a balance block system the loads on the pennants can be high, the route of the aft one in particular is complex, with several turning blocks. I don't think the loads on the sail are particularly high though. I replaced my 12 mm polyester lines with 8 mm Dyneema, which copes well.

do you think moving to dyneema has had any impact on how free it runs

Dylan

 

[prv]

do you think moving to dyneema has had any impact on how free it runs

I imagine it's the reduction in diameter that makes it work better, made possible by the extra strength / stretch resistance of dyneema.

Pete

 

[vyv_cox]

do you think moving to dyneema has had any impact on how free it runs

Dylan

Yes, it has made an improvement, possibly because the previous 12 mm may have been slightly large for some of the blocks. I cannot claim a major reduction in the load, which is inherent in the tackle. It has never been a problem, the halliard winch copes perfectly well. Friction is almost more of a problem when freeing a reef, when it is better to pull the clew line through by hand to pull the balance block back along the boom.

 

[Halo]

Had single line reefing for last 2 seasons.
I would say about 1 time in 10 something snags and needs sorting out. The lines seem over heavy to me so will go down a size when I replace them.
Main disadvantage is when hoisting the sail fully after being reefed at the end of the previous trip I have to use the winch to hoist the main up the last 1/3rd of the way due to all the lines then are getting pulled through and up to the cars.
Overall I am neutral about the advantages / disadvantages of the system

 

[Robert Wilson]

I watched a sailor cranking his single line reefing down using a fairly big winch on the coachroof

It really did look like a lot of strain being put on the sails and blocks

there was a lot of friction involved

has anyone tried single line and then gone back to two lines because there seemed to be just too much stress involved?

worried of Botolph Claydon

When I bought her, my Javelin30 had clew downhaul/outhauls and horns for the tack. Clew lines ran inside the boom with NO blocks at all. So I converted to single-line reefing (all three reefs) as I sail almost always single-handed.
Friction increased dramatically, so I've now got "in-boom clew downhaul/outhauls and a second line for tack cringles (3 reefs still).
It works better, but still a lot of friction so I'm going to fit pad-blocks on the boom and blocks at each luff cringle. Sometime........

 

[JimC]

are the blocks ones with bearings in them or just nylon bushes

I wondered if that was one reason why friction seems so high

I would guess that getting the geometry absolutely spot on is also pretty crucial

Dylan

I'm not at the boat to check but I suspect that the nylon pulleys just run on the stainless steel spindles without any intermediate bearing material. The bodies of the blocks are black nylon too, they are quite small.

As regards the geometry: the end of each reefing line is tied to an eye on the bottom of the boom, the eye is beneath or very slightly behind the point where the nylon block will come down to when the reef is pulled down. The rope then goes up the sail, through the nylon block, down the sail, round one of the pulleys on the end of the boom, through the boom to the gooseneck end, up the sail to the nylon block on the luff, down again to a block at the mast foot passing through a fairlead near the gooseneck on the way down, and back to a jammer on the coachroof.

The fairleads by the gooseneck are eyes attached to the side of the mast which ensure that the tack is pulled forward as well as down.

There is a lot of twisting and turning of the rope. I keep the pulleys lubricated but there is quite a bit of friction as the OP suggests. Nevertheless it all works OK. I mark the halyard at each reef position, let it out to that point, and winch in the reefing line as far as I can. Then I look up at the sail and usually find it's as it should be. Sometimes the nylon block at the leech hasn't quite come all the way down to the boom, another heave on the winch fixes it.

 

[Martin_J]

Dylan..

Are you also aware that there are a couple of very different reefing systems both of which could be called 'single line reefing' systems..

One is where the single line that you pull comes from a termination on the boom, up and back through the reefing eye on the leech, forwards through the boom and then up and back through the reefing eye on the luff before heading to where you are pulling from in the cockpit.

This method tends to pull the luff cringle down first making it very difficult to get the pull for the leach/tack end down. Sail can easily suffer from chafe as the line pulls through even if you have a pulley on the sail.

Second is where you still only have one rope to pull but within the boom it is magically split on a few pulleys so both luff and leech cringles have their own single line emerging from the boom. Yes - you pull on one line and two single lines get pulled in (one at the front and one at the back of the boom) both at the same time.

Second method.. so much easier to work with.. no chance of chafe.. requires special boom internals.. but is it really single line You only pull one so it must be!

 

[Martin_J]

Picture on page 14 of Selden guide showing the single line reefing that actually uses more than one line - but you still only pull one!

 

[Halo]

Yes, it has made an improvement, possibly because the previous 12 mm may have been slightly large for some of the blocks. I cannot claim a major reduction in the load, which is inherent in the tackle. It has never been a problem, the halliard winch copes perfectly well. Friction is almost more of a problem when freeing a reef, when it is better to pull the clew line through by hand to pull the balance block back along the boom.

Would you recommend a move to Dyneema lines for single line reefing ?? Is it mega expensive?

 

[prv]

Main disadvantage is when hoisting the sail fully after being reefed at the end of the previous trip I have to use the winch to hoist the main up the last 1/3rd of the way due to all the lines then are getting pulled through and up to the cars.

I don't stow the sail reefed, unless it's for a short time when I know the reefs will still be needed when re-hoisted. Otherwise, once the sail is down I undo the reef points, cast off the pendants, and pull them through. The loose line gets tucked into a fold of the sail. Then it always goes up easily. I have separate tack and clew pendants, but I don't see why you shouldn't do the same with single-line reefing.

What's always struck me as daft is the people who stow an un-reefed sail, and then pull all the reefing lines through to the cockpit to "tidy them up", thus creating the additional friction on hoisting for no reason whatsoever.

Pete

 

[Robert Wilson]

I don't stow the sail reefed, unless it's for a short time when I know the reefs will still be needed when re-hoisted. Otherwise, once the sail is down I undo the reef points, cast off the pendants, and pull them through. The loose line gets tucked into a fold of the sail. Then it always goes up easily. I have separate tack and clew pendants, but I don't see why you shouldn't do the same with single-line reefing.

What's always struck me as daft is the people who stow an un-reefed sail, and then pull all the reefing lines through to the cockpit to "tidy them up", thus creating the additional friction on hoisting for no reason whatsoever.Pete

I did that once - and only once!!

 

[Bav34]

No, to your questions.

We reef from the cockpit ... or rather Mrs Bav does, and it can be done in under three minutes.

The stresses seem no more than we put on the main halyard when on a beat.