Top-Down Furling

[Ragtime!]

We're seeing a move towards these furlers on race boats out here in the wild, wild west - especially on the sleds with huge masthead asymmetrics.  The latest converts are a hot new local McConaghy 38 . . . and my modest J/92.  The sail is a new, 94 s/m A2 with broad shoulders, which would never furl on a conventional bottom-up furler like I use on my reaching sails.  (I use a Facnor unit on my A0 and A3/5.)  This top-down Karver KSF-1 with Colligo's adjustable 9mm torsion line is the bees knees.  More details if you're interested.

[RJA Armstrong]

Bob,
Any pictures? How is code 0 working for you?
Bob A

On Mar 31, 2013 5:30 PM, "Ragtime!" <Bobsa...@yahoo.com> wrote:
>
> We're seeing a move towards these furlers on race boats out here in the wild, wild west - especially on the sleds with huge masthead asymmetrics.  The latest converts are a hot new local McConaghy 38 . . . and my modest J/92.  The sail is a new, 94 s/m A2 with broad shoulders, which would never furl on a conventional bottom-up furler like I use on my reaching sails.  (I use a Facnor unit on my A0 and A3/5.)  This top-down Karver KSF-1 with Colligo's adjustable 9mm torsion line is the bees knees.  More details if you're interested.
>
>
>
>

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[Ragtime!]

Bob A, I trust you can see the photos of the A2 and top-down furler in my earlier post.  If you mean the A0, I can't find any photos of it on this laptop.  I have a bunch of video of it during the '08 SHTP but I'm not the YouTube type (yet).

Here's the A3/5 on the Facnor (bottom-up) furler though.  Other than not rigging the bobstay under the sprit, this is the same set-up as the A0.

[RJA Armstrong]

Perfect! Thanks Bob! Hope all is well!
Bob A

On Mar 31, 2013 6:30 PM, "Ragtime!" <Bobsa...@yahoo.com> wrote:

Bob A, I trust you can see the photos of the A2 and top-down furler in my earlier post.  If you mean the A0, I can't find any photos of it on this laptop.  I have a bunch of video of it during the '08 SHTP but I'm not the YouTube type (yet).

Here's the A3/5 on the Facnor (bottom-up) furler though.  Other than not rigging the bobstay under the sprit, this is the same set-up as the A0.

[Ragtime!]

No bites of interest in the top-down furler, eh?  Think it's for cruisers?

Do any buoy racing?  Let me tempt you a bit:

1)  Did you watch any of the ACWS races last year or the Extreme catamaran series?  What they did was hoist a rolled gennaker on the last upwind leg and as soon as they rounded the top mark it was unrolled and drawing.  I can do exactly that with my big A2 runner, by myself.  There is no doubt in my mind that the kite can be full and drawing before the stern passes the mark.

2)  A downside of asymmetrics tactically is that you need to know which side you're going to set on.  Then you need to take it down on the correct side for the next set.  Jibe sets are slow.  None of the above with the furler.  You hoist the rolled sail on one side or the other - for me the rolled runner hoists from the port side of the boat and the rolled reacher from the starboard side, but that's easily reversable.  BUT once hoisted on the last upwind beat, you can unroll the kite on either side instantly.  Decide on a last-minute gybe after the top mark?  No problem, just grab the other sheet to unroll it after the main comes across.

3)  The mother of all gybes in heavy air . . . ours is under the Golden Gate on any Summer afternoon - we have this dude called the South Tower Demon.  Anyway, got one of those in a race?  No problem - roll up the kite part way, gybe the main and unroll the kite on the other side.

4)  No shrimping, ever.

5)  No dragging the kite across the boat on sets and douses, rips on the pulpit, etc.

6)  Come in low at the bottom mark and have to douse without bearing way off?  No problem - blow the sheet and roll 'er up.

7)  Messy rounding?  Get started back up the course and drop the roll to the deck when you get a chance.

 . . . and I'm not even selling the things!

[Max]

I have to admit : very, very tempting...

Except that -first- I should say "clips, or it never happened..."

:-)

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[RJA Armstrong]

Bob,
Sounds great! You have me sold. Would go great with the roller furler code 0.
Bob

[Ragtime!]

Max, I have to admit I've joined the "look at me doing something stupid" crowd and bought a GoPro.  It'll be here in a few days.

In the meantime here's an old video from Karver.  They're doing some of it wrong, like the furler drum is cocked 90 degrees on the sprit, causing a lot of drag.  But it gives you an idea.  The last minute or so they finally get some breeze:

http://www.youtube.com/watch?v=2kqlStOI4DA

[Max]

Bob,

I'm quite impressed as it seems to work so flawlessly…

I've been discussing about those systems with my local sailmaker, and he was not recommending them. To tell the truth, he was even selling a similar item (the Rollgen) that seemed heavier and bigger, but for racing…don't even think about it, he was telling me. But, I'm not such a kind of purist. I race with my beloved jib furler against all those hardcore racers that by no means would ever consider rolling their headsails. I understand these things are being refined continuously, so probably now the times are good also for these gennaker furling systems.

Many thanks for sharing this…and please keep us updated on how it goes…

Question - you mentioned about Colligo torsion cable…is this custom made or so or does the Karver come with its own torsion cable…

ciao

max

[Ragtime!]

Max,

For racing with full crew your sailmaker is probably right - you can probably do as well with conventional spinnaker handling.   I think the use of furlers on downwind sails will catch on though.  The large offshore racers are using them (Open 60's, Volvo 70's etc.) and they will be used constantly in the America's Cup races.

Regarding Roll-Gen, our local J Boat dealer experimented with that product several years ago (when the J/100 came out) and said it worked fine.  I think Karver is better known and able to market the top-down concept more effectively.

Regarding torsion cables, each one is custom for the boat, it does not come with the furler.  7mm torsion rope will fit in the jaws of the Karver furler and is strong enough but can twist a bit, so I had Colligo make mine out of 9mm stock - with the cover it's about 11mm.  I had to use shackles to fit it to the jaws in the bottom drum and top swivel.  All this takes some tinkering and the length of the torsion rope is critical - it must be tight to roll smoothly.  On mine, when I bone out the spinnaker halyard on the winch it pulls the tip of the sprit up against the top of its casing.  If the rope was shorter it would start to bend the sprit - if longer it would be loose and not furl as well.

One reason I bought the torsion rope from Colligo Marine is they make clamps for it that allow it to be adjusted in length.  These clamps are covered by the black heat-shrink in my photos.  Note that Colligo also sells a top-down furler and theirs has larger jaws - I think it's also cheaper than the Karver.  The Karver has a lock so it won't unwind accidentally - I think this is a benefit.

[Max]

Bob

what about the Facnor bottom-up furlers ? You mentioned that you are using them for A3/A5 which I guess shouldn't have a so straight luff : do they work OK ?

ciao

max

[Ragtime!]

Max, I bought the Facnor continuous-line furler several years ago to use with the Code 0, which is a flatter sail.  It's always worked well - I've posted here about that combo before.  Last year I tried the Facnor with a new A3/A5 (which is much fuller) and it still works okay.  The only problem is the sail rolls more loosely up high so I have to get the rolled sail down to the deck more quickly.  Much of this is my single-handing though.  If you were sailing with crew who could keep even pressure on the sheet while the sail was being rolled, it would work better.

The reach back up river to my current club gets closer to the wind the farther you go, so a furler on the reaching kite allows me to carry it longer than if I had to douse it conventionally.  In any wind, it would be difficult to douse without shrimping it - the wind is too far forward and the river is too narrow to bear off for the douse - I'd be in the mud.  I'm moving the boat back to the central Bay next week so I'll get to experiment with the furlers in more dynamic conditions.

[Max]

excellent - very interesting

many thanks and keep us updated !

max

[RJA Armstrong]

Bob,
Any idea how much that furler is for our boats?
Bob A

[Ragtime!]

Top-down furler update after the last couple of races:

First, to answer Bob A's question, the Karver KSF-1 runs between $1,400 and $1,700 depending where you get it.  I bought mine slightly used for $1,000 off the Sailing Anarchy classifieds, from a local guy who bought it for his Hobie 33 and then sold the boat.  I wouldn't have paid retail since the whole thing is an experiment.  If I was starting from scratch I might buy Colligo Marine's top-down furler (that's where I bought the torsion rope) since it's a little cheaper and I think would take less fiddling to get it working.

Additional costs are a custom-built torsion rope for your boat (I paid Colligo about $400) and a continuous furling line ($100-$200 including the splice).  I also needed some shackles (both hard and soft) and a 10x14 ferrule for the tack line.  You can probably use your old tack line and you can use your old sheets.  It needs to be a shorter-luffed kite - like around 44'.

This last Saturday I tried the furler while single-handing a 21 mile race around the central Bay.  TWS was 10-12 at the start building to 25+ at the finish, and I used the furler in approx 12-16 knots.

I had it ready to go at the windward mark, released the furling line, pulled on the sheet and it wouldn't unfurl.  It was a rigging problem.  I'd wanted that last 3-4" of hoist so I'd shackled the spinnaker's head ring as high on the top line terminator as I could.  Problem was, the stiff head of the spinnaker was stuck against the mast up there so it just reverse-twisted when I tried to unroll it.  Of course I couldn't see that from the cockpit.  I dropped the halyard a few feet, went up on the foredeck and worked the constipation out of the roll, re-hoisted and then it unrolled fine.  I'll lash the head of the kite a bit lower on the line terminator and that problem should not recur.

It was GREAT at the leeward mark - which was actually a pair of little islands in the north Bay called The Brothers.  Most boats doused early but I carried right into the turn upwind and rolled it up.  I picked up several boats just on that maneuver.  I couldn't drop the roll right away so I started short-tacking up the beach (we were fighting current).  On one tack I dropped the roll and shoved it down the forward hatch, then on the next tack I pulled in the sprit and finished cleaning up.

I plan to keep working with it but I think we're getting close.

How did I do in the race?  A strong cross-current at the pin had me passing it closer than I planned (the pin was heavily favored) and I splashed it going by.  But at the end of the LONG day I was cleaning up the boat and saw a bit of yellow on Rags' dark blue hull - so I RAF'd.

Bob J.

[Ragtime!]

I've given the top-down furler a good test, tried to work out the bugs, etc. but I'm taking it off the boat.

It takes longer to roll up the sail than to douse it conventionally, it rolls so tight from the head down that it's hard on the sail, and the tack line twists around the torsion rope when you unroll the sail, even if you keep the tack tight initially.  This prevents you from easing the tack for running and from rolling the sail back up.

Good concept but I think there's a reason they don't show videos of it in anything but light air.

The Facnor code zero furler has always worked fine and I'll keep using that on the CZ, but I'll go back to conventional handling with the fuller downwind sails.  It's not that hard.