# Top Down Furlers



## Yachtjuno (May 26, 2013)

I have a genneker with a snuffer on my 59ft Oyster monohull and I find it too hard to use short-handed so the sail just sits in the lazarette taking up space. I am considering getting a Karver top-down furler and i wonder if anyone has any experience using these at sea. They look and sound good in theory and i know that the Volvo boats use them offshore. Feedback from happy users out there would be most welcome.


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## Tim R. (Mar 23, 2003)

I just purchased a Selden GX15. I have deployed and furled the sail in light air at the slip but not while sailing. I am leaving for a 2 week cruise today and plan to use the furler extensively. I also plan to film it in operation and post to my website.

I previous had an ATN sock and tacker and did not like wrestling with it on deck. Snubbing the sail if the wind increased suddenly was always difficult and prompted me not to use it very often.


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## Yachtjuno (May 26, 2013)

Thanks Tim,
I would be very interested to hear how you get on. 
Regards
Paul


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## overbored (Oct 8, 2010)

The flatter the sail the better they work. A Gennaker does work better then a spinnaker. a Gennaker is really a asymmetrical spinnaker. they both have a soft luff. if you are using a reaching asymmetric they work well if the sail is designed for it. The head needs to be soft with out a lot of stiffening panels. an extending spinnaker crane on the top of the mast helps to keep the torque rope out away from the forestay and furled jib. The stiffer the head of the spinnaker the more the sail tends to hang up on the forestay as the torque tries to wind the sail around the torque rope. This causes the torque rope to wind up and twist like a rubber band on a model airplane and once the head does start to wind up the sail it will release the twisting and over wrap the sail. The sail will look like it is wrapped up just fine until the next time you try to unfurl the sail and it will be wrapped around the torque rope and will not unwind properly. Then comes the very messy take down. a bow sprit also helps a lot because for the furler to work properly the torque rope needs to hoisted tight and free to wind up the sail without it dragging on the forestay or furled jib. Get the stiffest torque rope you can for size of your boat. When furling the sail, if the torque rope gets any wind up, the sail will not unfurl the next time. Carver makes a good rope and furler but will still over wrap if not handle by an experienced crew, it is not something that can be done by one person like all the ad videos, where they show it being done in very light wind. The more wind the more crew skill needed to make it work and it takes practice like any spinnaker hoist and douse. The new Profurl looks like a good idea with the furling beads on the torque rope. I have yet to try one but just the fact they invented the idea lets me know that they were having the same problem with wind up and sail over wrap as the other manufacturers do. They don't talk about it unless you ask and if they tell you it does not happen then don't buy from them. the Volvo 70 guys have a very fast boat so they sail downwind with different apparent wind angles so they have very flat sails compared the one for a cruising boat. they also make it look simple but they have a lot of practice under their belt. most of their sails are hard luff sails like a jib or code zero. if one is trying to fly a old symmetrical as a asymm. on a furler then forget it.


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## Yachtjuno (May 26, 2013)

Thanks Overbored for taking the time to share your experience.
I have just had a bowsprit made with a 2:1 tack line that runs through the pole and back to the windlass and the furler will connect to that. I have also recently upgraded my spi halliards to dyneema so i think i should be able to get decent tension on the stay. My kite is more a reaching asymmetric so i am hoping it will suit. I will check the head as you suggest. Allspars in the UK supply the Karver product and they use a Navtec stay - the larger size apparently. They have also offered to crew on my boat at the regatta in October to show me how to use it. I think i will go for it - i find the snuffer just too hard in a rolly sea.


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## overbored (Oct 8, 2010)

here is some more stuff to read. I also heard that the Navtec stuff is the best. I have not tried it but was thinking about getting some. they are the most expensive. if you get it Let us know how it works


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## knuterikt (Aug 7, 2006)

*Furlers for asymmetric*

I have no experience (yet) with top down furler.

I have a Facnor AFX with a central furling line.
The difference from a top down is that it have a swivel top & bottom and a thin line attached mid luff that is used to furl the sail from the middle.

The sail I'm using has can be used in a wide AWA angle from DDW to 90° by adjusting the stretch on the luff. 
The only adaptation for the furler is a reinforced eyelet in mid luff.

It's important that the head and tack can rotate freely during the furling process.

Here I'm sailing DDW with the tack eased, you can see the furler flying, the furler sits on a 1:2 tack line that can be adjusted from the cockpit.









In this picture you can see the central furling line going to the torsion stiff rope.









The tack swivel









Head swivel









Maybe I'm wrong but I think Facnor has patented this design..

I'm planning to convert my system temporarily to a top down just to compare the two different designs - out of curiosity


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## Yachtjuno (May 26, 2013)

thanks Knuterikt
i havent seen your system before. its be interesting to see how the top down compares. i will certainly report back on this thread how i get on once i have it installed around the end of September.
i definately need a light air solution for the world ARC which we are planning to jon next year.


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## overbored (Oct 8, 2010)

I have the same system and have a lot of problems with spinnaker over wrap. we tried the furler as a top down and found that the torque rope is way to light to handle top down furling. there is way to much twist in the rope by the time the top starts to wind up. it does work on the the A4 and A3 but not on the A2 it is to big


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## knuterikt (Aug 7, 2006)

overbored said:


> I have the same system and have a lot of problems with spinnaker over wrap. we tried the furler as a top down and found that the torque rope is way to light to handle top down furling. there is way to much twist in the rope by the time the top starts to wind up. it does work on the the A4 and A3 but not on the A2 it is to big


So you are using the AFX?
What model furler and size of sail?

Have not had problems like that - but both the tack and head spin freely (not touching anything)
But furling with to much pressure on the sheet can case uneven furling. 
It's installed with torque rope supplied by Facnor.


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## overbored (Oct 8, 2010)

that what I have same type with the swivel at the top and bottom. i works on the smaller spinnakers but not on my to big ones which are 1000 SQ ft ( 93 s m )and 1200 Sq ft (112 sm) the Facnor rope is not as stiff in torsion as the colligo but it is also 8 mm vs 11 mm. we are using the 11 mm colligo set up for top down and it works much better. Still we have to be very careful when doing the big sail. it has a 47' luff with a 33 ' foot. takes a bit to furl.


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## Yachtjuno (May 26, 2013)

Thanks everyone. I have ordered the Karver furler with the Navrec stay. Will let you know how it goes.


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## knuterikt (Aug 7, 2006)

I did a test conversion to top down on my AFX, temporarily disabling the top swivel so turning the anti twist rope would turn the head of the sail.

I did this on a day with wind speed = 0.

After lots of pulling on the furling line the top of the asymmetric started to furl after the first 3 feet (= 1 m) I stopped as I noticed that the rope where twisted a lot..

From this little test it's obvious that top down needs a better anti twist rope than the AFX central furling line design.

Checked with the local rigger, seems there is a rapid ongoing evolution with the anti twist ropes.

Mine is probably the first generation rope for the AFX system, Facnor sell better anti twist ropes and there are also others who make competing products.

The Facnor way of attaching the rope to the swivels make attaching some of these ropes a demanding task.
Facnor uses a wedge in the middle of the core to attach the rope - some of the ropes one can buy use lots of glue in the core so its difficult to get the wedge in place.


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## capecodda (Oct 6, 2009)

We are using a code zero (G0 from North) on a Schaeffer roller, but it's not this top down design. I too am very interested in hearing more. Been thinking about a asym, and this system looks intriguing. We are fractional with a good attachment point forward of everything (we made the anchor roller a little longer) so we can tension the torque rope pretty well.


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## JonEisberg (Dec 3, 2010)

knuterikt said:


> I did a test conversion to top down on my AFX, temporarily disabling the top swivel so turning the anti twist rope would turn the head of the sail.
> 
> I did this on a day with wind speed = 0.
> 
> ...


That's good information, thanks...

I haven't yet had the chance to use a top-down furler myself, but I have some reservations whether or not they're quite there, yet...

I'm thinking about having a new Code 0 made, with the possibility of a high torsion rope built into the luff... I use the ordinary Facnor furler, and my current Code 0 has always just had a spectra luff... It takes a lot of wraps at the bottom of the sail before the furling starts to 'migrate' up to the top, and unless you twing the sheet further forward to exert a strong downward pull on the leech, you'll usually wind up with some loose sailcloth up at the top...

My water generator uses a high-torsion rope, and it's not easy stuff to deal with... One of the things I really like about my Code 0 as is, is with the softer luff, it can be stowed in an incredibly compact package. I'm concerned I'll wind up with a much bulkier package if I go with a high-torsion rope... So, we'll see, but I may wind up simply going with what I've got again, it's not that difficult to deal with...

With an asym, I still think a sock is the way to go on smaller boats, but of course I'm not sailing a boat the size of the OP... Biggest rig I've ever used a sock on was a Trintella 50 - which is a massive rig for a boat of its size - and it definitely was a challenge to manhandle when the breeze came up, we often had to lead the downhaul to a winch to begin the capture of the sail...


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## Tanley (Aug 20, 2009)

Tim R. said:


> I just purchased a Selden GX15. I have deployed and furled the sail in light air at the slip but not while sailing. I am leaving for a 2 week cruise today and plan to use the furler extensively. I also plan to film it in operation and post to my website.
> 
> I previous had an ATN sock and tacker and did not like wrestling with it on deck. Snubbing the sail if the wind increased suddenly was always difficult and prompted me not to use it very often.


So what's the verdict? Curious to get your opinion on it.


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## Tim R. (Mar 23, 2003)

I was out cruising for two weeks and used the Selden GX 15 furler 3 times. It worked great after a little tuning. I am very happy with how it works and how easy/quick it is to deploy and retrieve. I made a quick video showing how nice it works. No real specifics on the video but it shows unfurling and furling.

The real advantage IMO is that you can hoist the sail in the morning not knowing if you will use it. With the ATN sock I had to carry the huge bag up on deck and hoist the sock/sail and attach the tacker every time I wanted to use it. This usually meant I would not bother using it if I had a broad reach or DW leg less than an hour. With the furler I can easily roll it out for 5 minutes if I want.

You cannot leave it up indefinitely as there is no UV protection for the sail. We hoist it before setting out if we think we will have any broad or DW legs. It is also much easier to setup last minute if needed.

And it rolls up into a space less than half the size when it was in the sock so transporting and storing the sail/furler is much easier now.

Here is the video:


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## Tanley (Aug 20, 2009)

Looks great, thanks for sharing. Agree about the inconvenience of sock. This might be a nice addition to our inventory.

Hard say for sure in the video, but it looks like the tack is inside your bow pulpit. No sprit needed? If gybing, would you just furl/gybe/deploy? Same DW angles that you saw with the assym?


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## Tim R. (Mar 23, 2003)

Tanley said:


> Looks great, thanks for sharing. Agree about the inconvenience of sock. This might be a nice addition to our inventory.
> 
> Hard say for sure in the video, but it looks like the tack is inside your bow pulpit. No sprit needed? If gybing, would you just furl/gybe/deploy? Same DW angles that you saw with the assym?


The tack is inside the pulpit. I have a lot of space between the headstay and the pulpit. No need for sprit on our Caliber. No need to furl when jibing. Sheets are led for outside jibing. Same procedure as if there is no furler.


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## albanychris (Jan 28, 2014)

I am trying to build a top down furler for my 8m yacht.
There are 2 things I dont understand. 
1. Why is it necessary for the tack to be on a rotating bearing independent of the bottom unit. Could it be stationary but independent of the turning parts?
2. What causes the bottom of the sail to start turning at a certain point in the furling process when an independent swivel for the tack is fitted? I have watched the videos over and over and I can't work it out.
Cheers


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## knuterikt (Aug 7, 2006)

albanychris said:


> I am trying to build a top down furler for my 8m yacht.
> There are 2 things I dont understand.
> 1. Why is it necessary for the tack to be on a rotating bearing independent of the bottom unit. Could it be stationary but independent of the turning parts?


No.


albanychris said:


> 2. What causes the bottom of the sail to start turning at a certain point in the furling process when an independent swivel for the tack is fitted? I have watched the videos over and over and I can't work it out.
> Cheers


Top down furlers is used on asymmetric sails that can't be furled around it's luff. To make a mental picture start with the sail unfurled and hoisted.

The furling wheel/drum transfer the rotation to the bottom part of the top swivel by a stiff rope (anti twist rope).

The purpose of the top swivel is to let the bottom part rotate without twisting the halyard.

The head of the sail is attached to the bottom part of the top swivel.
So when you start to furl in, the top of the sail will start to wind onto the anti twist rope at the top.

As you continue to furl more and more of the sail will get wound onto the anti twist rope (top down).
When the whole length of the luff is wound onto the anti twist rope the tack need to rotate with the rest of the sail.

That's the reason for the swivel at the bottom. 

Without the swivel the sail would start to furl along the full length of the luff at the same time and just make a big knot of the sail.
With the tack attached stationary the sail would be ripped in two when the whole luff is onto the anti twist rope and you start to furl in the foot of the sail.

If you are contemplating to make your own, it should be easy to make a Mock-up with an old bed sheet, some rope and a swivel


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## Yachtjuno (May 26, 2013)

I said that i would feed back on my experience with the top down furler that i was planning to install on my Oyster 57.5 monohull. So here it is:
I have a short carbon bowsprit made by Formula, a Karver KSF5 top down furler and a Navtec custom stay. I have re-used my cruising chute with no modification other than to change the hard ring at the head with three straps so that it furls more neatly at the head. The most complicated part was drilling a hole in the wall of the stemhead to secure the prodder.
I have to say that i have been delighted with the outcome. I simply attach the sprit to the stemhead with its shoot bolt, attach the furler to the sprit with a shackle, attach the sheets to the clews, haul the furled chute up with the spinnaker halliard and then pull on the sheet to unfurl. Furling is easy too - even under load in 15 knots i was able to do this by hand, although its easier on the primary electric winch. Because the sail is furled around the stay it take s up much less volume in the sail locker although on passage i intend to stow it in its bag on the foredeck.
Lessons that i have learnt are: 1. Lots of people make the furling units but the Navtec stay is the critical part (but expensive). 2. The furler unit on the prodder must be fixed. I had it attached on a 2:1 tack line and it kept twisting so i have fitted a pad eye on the end of the prodder and now its fine. 3. Lots of halliard tension. 4. When unfurling don't be tempted to control the furler or it can overrun and get tangled. Just let it run all the way out.
I have been out and used it with my wife in 15 knots with no concerns at all. We would never have used the old snuffer in those conditions. So i highly recommend it but the real test will come when i use it on our transatlantic planned for November this year.
Thanks everyone for all their helpful comments.


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## Faster (Sep 13, 2005)

Thanks for coming back and filling us in!


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## knuterikt (Aug 7, 2006)

*Furler for assymetric - update*

I have sailed with my Facnor AFX 2500 since the May 2009.

This spring I decided to do some upgrades.

It has been a tremendous development on the construction of anti torsion rope in these five years.
To the right in this picture is the old rope - three layers 
- core
- some rubbery sleeve (only to keep the fibers in a bundle)
- Cover
To the left the new rope - four layers
- core similar to the old
- Inner braid (white) made of some stiff thin fiber
- Intermediate braid (black) made of some stiff thin fiber
- Cover assimilate to outer on the old

The new rope is significantly better to resist torsion (might be unfair compare used to new - but I seem to remember that the old one was almost the same when new)









The endless furling line on the system had increased in diameter since new initially 8 mm now almost 9 mm and the surface had gotten "fluffy".
I decided to replace this, double braid polyester/polyester.
New ropes have been developed for this use also, I bought some Marlow ropes MGP furler 50 MGP Furler 50
It's made of Vectran® / Polyester blend cover, Polypropylene Core
Here is a picture I took during the splicing, notice the tight braid on the core, will give better form stability.









In a system with endless lines it is important to have as little friction as possible in the system
In my old setup I had to double ball bearing blocks to lead the line back to the cockpit, It worked but the problem with blocks is that they only reduce friction when the rope is running over the wheel.
The block housing will induce friction if/when the rope rubs against it - I found that often my blocks would hang on the rope..
The furling line was/is lead more or less direct aft from the bowsprit along the cabin side to an attachment between my two sheet winches.
I got rid of the two blocks, replaced with
One Selden furling line guide attached to the tubing of my self tacker attachment.
One 50 mm SS ring hanging of the pulpit with a shock cord.
The selden furling line guide, this can be opened with one hand to take the line off.
Hopefully this will make me better at taking the hole furling system off when not in use..









This is a picture of the central furling line used on the Facnor system









The adjustable tack on my bowsprit, the combination of the stiff 10 mm Dyneema tack line and the distance between the two points (attachment and strop with thimble) prevent furler from twisting.
This way it's easy to adjust the tack height and thus the fullness of the sail.
I must pull the tack back down before furling. 









The adjustable tack also give me a safe way to use the spinnaker boom on DDW.
I have a guy attached to the bottom of the furler(=tack), by easing the tack line and winching in on the guy I can pull the tack to windward and use it as spinnaker.
The tack is always ready to pull the tack/drum down to gybe or furl the sail.









Video showing the furler in action (no sail)


The tack of the sail 









It was a little bit difficult to dismantle the system, it was put togheter using liberal amounts of locktite.
The roller bearing balls are made of delrin so it is important to be carefull with heat.
On assembly I decided to modify the design, replacing the set screw and locktite with a rigging bolt through the whole assembly.

The special clamping tool made to dismantle the top swivel (you can use a spanner on cone, the the other part is round).









From the other side


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