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Old 10-03-2010, 02:44   #106
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Originally Posted by bewitched View Post

As for the strength of the storm jib where it attaches to a luff groove - I don't know what material is used or it's strength. Maybe ask these guys, they all produce such a sail.

Quantum

UK Halsey

North Sails

Or maybe these guys - sailing in the 1998 Sydney Hobart in horrendous conditions, using sails in luff grooves and going on to win overall

Midnight Rambler
I agree. That luff construction, which Nick kindly illustrated, is strong as hell. I am too lazy right now to calculate the loads but I'll bet dollar to doughnuts that this is not the weak point of these systems. The sail cloth is doubled there in that slot and the load is at an oblique angle on both sides. The sail itself will rip long before the luff gives up.

Whether or not a heavy-cloth storm jib will fit in a luff groove, I have no idea. Obviously if it doesn't fit, it's no good. Our staysail is specifically designed to be used as a storm jib (according to the Moody manual) and is constructed of very heavy 9.5 oz. Dacron. It fits in the luff groove fine. I don't know if pure storm jibs are made of even heavier cloth. The ones available here:

The Sail Warehouse - Storm Sails

all have slightly lighter cloth than my staysail, and are available with either hanks or luff tape. The site advocates the dual use of a storm jib as a staysail on the inner forestay of a cutter, so the Moody practice must not be unique.

All in all, I don't see why there should be any problem with the loads of my 23m2 staysail/storm jib being carried in about 60% of the luff length of the same type of furler as my 77m2 yankee jib. The pressure per linear centimeter of luff will be higher, but the staysail is made of much heavier cloth than the yankee, and the luff tape is a very strong system.

My rig looks like this (catalogue shot of an M54; not my boat):
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Old 10-03-2010, 04:42   #107
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What a great debate.

Quote:
Originally Posted by SurferShane View Post
I have a steel H 28 Ketch with a staysail and have decided to go against the modern trend for furlers and am sticking with a number of hank-on headsails. The way I look at it is that the sails on the boat are fairly small and easy to handle, so why not have a few different specific sails for different conditions?
Going back to the original post and some lower wind strengths, because we won't be sailing in 65 knots ever , I popped into Lucas Sails last night to discuss the conversion of our recent sail purchase off e bay. Turns out it's a 200sq foot jib (as apposed to 310 sq feet for our large Genoa). It's also the first time we have seen the sail laid out and is in "as new" condition, bargin

Lucas will cut off the hanks and convert to RF for us and extend the length of the luff to full height so the RF slide lives at the top of the RF to avoid any halyard raps.

The plan then is to hoist this if the wind strength looks higher than F4-5 before we go out rather than the existing 130% genoa. It should mean full sail in F4 and only a small roll in F5, finally a spare incase our elderly Genoa blows out mid voyage.

This is the exact opposite to Shanes idea of using hanked on sails, but uses RF to the same advantages of choosing a sail to match the likely conditions, afterall there is no "one solution fits all" and whilst less convienent that a twin RF its a lot cheaper and simplier.

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Old 10-03-2010, 06:28   #108
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What a great debate.



Going back to the original post and some lower wind strengths, because we won't be sailing in 65 knots ever , I popped into Lucas Sails last night to discuss the conversion of our recent sail purchase off e bay. Turns out it's a 200sq foot jib (as apposed to 310 sq feet for our large Genoa). It's also the first time we have seen the sail laid out and is in "as new" condition, bargin

Lucas will cut off the hanks and convert to RF for us and extend the length of the luff to full height so the RF slide lives at the top of the RF to avoid any halyard raps.

The plan then is to hoist this if the wind strength looks higher than F4-5 before we go out rather than the existing 130% genoa. It should mean full sail in F4 and only a small roll in F5, finally a spare incase our elderly Genoa blows out mid voyage.

This is the exact opposite to Shanes idea of using hanked on sails, but uses RF to the same advantages of choosing a sail to match the likely conditions, afterall there is no "one solution fits all" and whilst less convienent that a twin RF its a lot cheaper and simplier.

Pete
Sounds like a great plan. If you have two luff slots in your RF foil, you can hoist both of them, too, at the same time, in a quasi-twizzle rig for downwind work.
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Old 10-03-2010, 06:43   #109
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Sounds like a great plan. If you have two luff slots in your RF foil, you can hoist both of them, too, at the same time, in a quasi-twizzle rig for downwind work.
Now funny you should mention that, because we do. Interestingly I read a book before Xmas about an Atlantic crossing using the twizzle rig, hence my interest when Newt said he was exploring this idea. Anyway the boat used twin 200sqft jibs sewn together for the twizzle rig on a 31 foot boat.

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Old 10-03-2010, 07:00   #110
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Now funny you should mention that, because we do. Interestingly I read a book before Xmas about an Atlantic crossing using the twizzle rig, hence my interest when Newt said he was exploring this idea. Anyway the boat used twin 200sqft jibs sewn together for the twizzle rig on a 31 foot boat.

Pete
I'd like to try it to. We also have two luff slots (I guess most roller furlers do). I understand that this rig is very, very stable and efficient and better than anything for sailing dead downwind. I reckon the two jibs could be of different sizes.
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Old 10-03-2010, 08:42   #111
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I have sailed with twin head sails a lot, but that was on a rig with two head stays next to each other and hank on sails. (we're still comparing hank vs furler, right?). It worked great, pole to the windward sail and a jealous eye to boats with two poles. (sloops that sail of shore a lot should have two poles).

I loved the setup.

When you do the same with a double-groove furler, there are two things to keep in mind:

1. the pole(s) should be adjusted so that you can furl the sails without removing the pole(s). This is easy to do and it kind of transforms the furling control line into an accelerator pedal.

2. between the luffs of the two sails you will have the furler foil. The twin head stay setup will have a gap there. It is said (but I was never able to confirm it myself) that the lack of that gap makes the boat roll more (oscillating roll). The dynamics of that sound logical to me (air can't escape through the gap so spill over into the other sail).
A solent stay with furlers for both head- and solent stay might well be the best solution here.

ciao!
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Old 10-03-2010, 09:09   #112
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SR,

Running I would think you want your sail's center of effort forward of your keel, so whatever does that.

You need the trysail or deeply reefed main if you're hoving-to or trying to reach.
Thanks HR...sort of what I figured too.
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Old 10-03-2010, 11:30   #113
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This would represent 65knots in one direction, coming to a complete stop and then coming at 180 deg at 65 knots in an instant. It's not going to happen.
If you sail near mountainous areas at high latitudes it can most definitely happen. The wind does remarkably sudden and radical shifts. I've had it happen to me, but fortunately at anchor. The wind shifted 180 degrees and the boat heeled over further than ever before, toe rail far underwater--and stayed there for about 30 seconds--all at anchor. And this was a boat with a B/D ratio of point 41 (stiff boat).

I think's Nick's approach has merit. Stuff breaks when the unexpected happens. When you get down to storm sails, bomb proof is the objective. I think it's real difficult to argue that furling systems are bomb proof. Admitedly nothing is bomb proof; it's all relative. But furling systems are on the wrong side of the spectrum. That's a fact of life.
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Old 10-03-2010, 12:38   #114
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I'd like to try it to. We also have two luff slots (I guess most roller furlers do). I understand that this rig is very, very stable and efficient and better than anything for sailing dead downwind. I reckon the two jibs could be of different sizes.
Whilst sails for a 31 foot yacht crop up fairly regularly on e bay, you might have a problem if you need a cheapy to test the idea with, dread to think what a new Genoa for a Moody 54 costs, however all is not lost . I have a friend whose wife makes bean bags out of old sails for folk in London who have too much money. The old sails come from the tip next to the Itchen Bridge in Sarfhampton. Bit of a lucky dip because each sail bag is £5 and you don't really have the chance to inspect them, but the big ones have little market appeal so tend to hang about longer. Spring seems to be the best time as the racing crowd replace last years sails.

Now there is a new 200sq ft laminate finishing on e bay in a couple of days which would suit a little Moody

Pete
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Old 10-03-2010, 13:05   #115
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I believe fullers are fine if you're in fine weather near home, but they are not for offshore.

As mentioned above, you can have reefs in hank on sails. I have a reef in my working jib & I use it regularly.
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Old 10-03-2010, 22:21   #116
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Stuff breaks when the unexpected happens. When you get down to storm sails, bomb proof is the objective. I think it's real difficult to argue that furling systems are bomb proof. Admitedly nothing is bomb proof; it's all relative. But furling systems are on the wrong side of the spectrum.
Hank on storm jib flown from an inner stay and backed up with checkstays

Simple, Strong, Reliable and Proven system - I'm not in any way suggesting that a fulrling system is an improvement on this.

But what actually make a furling unsuitable for a storm jib?

Regardless of our opinions on the matter, there are a huge number of sailing boats out there who simply don't have the option to hank on a sail to a wire / dyform stay. I would even hazard a guess that most sailing boats don't.

So why is a furler not suitable and a hank on is? In terms of load transfer they are very similar indeed.

They both tranfer load from the clew of the sail to the boat via the jib sheet

They both transfer load from the head of the sail to the boat via the halyard

How the tack is dealt with is slightly different with each - a hank on sail will normally attach directly to a strong point on the deck, whereas as a tack on a furling sail will attach to the furling unit its self. The load being transferred via the unit to the chainplate. Both are robust - certainly stronger than the sail.

So the only real difference I can see is the way that load is transferred to the forestay. But this is not a heavily loaded element. The calculation is beyond me, but I'd be very surprised if it's even close to 10%. For the Bene 45 example, that would be about 100kg after applying generous safety factors - peanuts.

And even if this element does fail and the sail does come out of the foil, what's the big drama? It's still attached at the head, tack and clew - it's not going anywhere. Flying these sails without a stay at all is not unheard of.
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Old 11-03-2010, 01:54   #117
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I believe fullers are fine if you're in fine weather near home, but they are not for offshore.
Why is that

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Old 11-03-2010, 02:10   #118
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Hank on storm jib flown from an inner stay and backed up with checkstays

Simple, Strong, Reliable and Proven system - I'm not in any way suggesting that a fulrling system is an improvement on this.

But what actually make a furling unsuitable for a storm jib?

Regardless of our opinions on the matter, there are a huge number of sailing boats out there who simply don't have the option to hank on a sail to a wire / dyform stay. I would even hazard a guess that most sailing boats don't.

So why is a furler not suitable and a hank on is? In terms of load transfer they are very similar indeed.

They both tranfer load from the clew of the sail to the boat via the jib sheet

They both transfer load from the head of the sail to the boat via the halyard

How the tack is dealt with is slightly different with each - a hank on sail will normally attach directly to a strong point on the deck, whereas as a tack on a furling sail will attach to the furling unit its self. The load being transferred via the unit to the chainplate. Both are robust - certainly stronger than the sail.

So the only real difference I can see is the way that load is transferred to the forestay. But this is not a heavily loaded element. The calculation is beyond me, but I'd be very surprised if it's even close to 10%. For the Bene 45 example, that would be about 100kg after applying generous safety factors - peanuts.

And even if this element does fail and the sail does come out of the foil, what's the big drama? It's still attached at the head, tack and clew - it's not going anywhere. Flying these sails without a stay at all is not unheard of.
I think the logic here is flawless.

If a furler jams or a furling line breaks for some reason, the result is that you simply can't take in the sail remotely. It's a storm sail, so likely sized so that it can stay up in almost any wind, so this is unlikely to be any kind of tragedy. Unlike the situation where this is a working sail which is dangerous if not reefed down.

Anyway, modern roller furling gear is pretty bullet-proof. I have only ever had one incident with it in decades of sailing with it, and that one incident was pure operator error.

Luff tape just blowing out of a RF foil, while the head and tack are still attached, is something I have never heard of. I think it must be practically impossible; it would take a load much larger than the sail itself could withstand. Luff tape is structurally and mechanically a better way to transfer loads to a stay, than hanks. The load is evenly spread out over the entire length of the luff, and there are no stress points of the kind you have with hanks. Not that there is anything wrong with hanks, but luff tape is even better, from a mechanical point of view.

So I don't see any problem whatsoever with using a storm sail on roller furling, if someone needs to, or wants to.

If we're talking about roller furling on the forestay, it might be more convenient, however, to hoist it over the furled, regular headsail, a la "Gale Sail". The big advantage of that is that you don't have to handle hauling down the regular headsail, which is not a task I would relish if the wind is getting up. That's the big disadvantage of roller furling altogether -- much harder to get a sail down, compared to hank-ons, maybe even impossible in some conditions.
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Old 11-03-2010, 05:59   #119
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Luff tape just blowing out of a RF foil, while the head and tack are still attached, is something I have never heard of. I think it must be practically impossible;
I have had luff tape blow out several times on various boats. Not under storm conditions either. I suspect a worn groove was the cause, or slightly mismatched tape/groove size. The special regulations for offshore races requires storm sails to have "b) for each storm or heavy-weather jib, a means to attach the luff to the stay, independent of any luffgroove device."

Also most headsails (even storm sails) are not built to be free flying. That requires a special reinforcement on the luff.
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Old 11-03-2010, 10:41   #120
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As I stated, it is simply my belief that roller furlers are not good in heavy weather. One needs only to look around any marina to see that most people don't share my belief. I've seen them break out numerous times just sitting at the pier in a blow. On one occasion, it took down the rig with it. I know the Pardeys are not big fans either. When I saw them they had many photos & stories of furlers gone wild. I did a Bermuda trip with a cutter on which all sails were roller furling. It was pretty handy when the weather was nice, but when it wasn't it took 3 men and a boy to take in the main. I can't tell you how many times I wished for a simple slab reefing setup. Aside from failures and iffy sail shape, when reefing, you want to bring your center-of-effort in & down. When you furl your jib into a stormsail you move it up & out.
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