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Old 27-02-2006, 13:36   #1
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Roller / Reef Furling Genoa basics

Ookay.. I have to preface asking for forgiveness in asking basic questions. I tried to do research and couldn't really find an answer but couldn't.

It has to do with a Genoa.

I kinda understand what the purpose of a Genoa is.

In the research that I have done, most circumstances if you have a roller furling setup, you can not reef the Genoa, it's either totally in or totally out. What I have learned is because of possible sail damage.

Now I have also read somethinga bout a reef furling system that allows you to reef a Genoa. So, if this is the case and you had a reef furling sytem, wouldn't it just behoove you to have a 150% Genoa and use that?

Why doesn't everybody just have a reef furling sytem? Does it come down to cost?


Clarification is greatly appreciated.
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Old 27-02-2006, 14:24   #2
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Sail shape

Improvements like foam luffs and sail cut have made roller furling to be somewhat roller reefing. Somwhere around 25% of a properly built sail can be roller reefed. Otherwise, the sail will still have decent shape and can be used almost as efficiently the unfurled sail.

The problem is when you try and reef beyond that point. The sail loses it's proper shape and starts putting undue strain on the sail. Forces working on the sail no longer pull in the direction of strength of the cloth, possibly blowing it out of shape.

Mostly it's a problem going to weather, where sheet loads are the greatest, and the most efficient sail shape for racing. Off the wind, you can get by cranking more of the sail in. A sail change would be a whole lot better, however.

If you sail in a predominately light air area like the Chesapeake or Long Island Sound, a 150% might work for roller furling. For long distance voyaging and moderate wind areas, 125%-135% is the best size compromise for reefability and full sail drive.

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Old 27-02-2006, 15:02   #3
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MaineCub,

Like most things, the answer depends as much on personal preference and sailing habits as it does on cost I would think.

My last boat (San Juan21) had an roller furling 135% headsail on a wire luff roller. It worked, most of the time but had the advantage of being able to easily drop the whole thing and then being able to use my hank on working jib. I always completely furled or unfurled it, then dropped it and raised the jib when shortening sail. This is an older type of system, not sure if you could find it new. It was my first experience with furling, and I prefered the hank on.

On my current 28' boat, we have a furlex system, with a double grooved foil head stay. We did not install the system, it was on the boat when we bought it, so I had little choice in the matter. The headsail is a 150% and we partialy unfurl it all the time. I guess the design of the San Juan 28 really needs at least some headsail to balance. Even with just a scrap out the boat sails better. I tried sailing with just a reef in the main in about 20-25 kts of wind, and about a 2-3 foot seas. We were close hauled, moving along at about 4 knots with 15 degrees of heel, but we were bouncing around and the motion was very uncomfortable. I pulled out just a tiny scrap of the head sail and we heeled over to about 20-25 degrees and the boat shot up to 6-6.2 knots. Rather than hobby horsing, we charged through the chop. It was exhilerating.

I am not a full time cruiser, most of my sailing trips are daysails on Tampa Bay, and short weekend hops along the coast in the Gulf of Mexico. So this system suits me fine as most of my sailing is solo it is one less thing I have to expend energy doing (well there is usually another on the boat, but she isn't interested in pulling strings, or if its my dad he is taking a nap). I think that with another active crew member, handling hank on headsails on my size boat would be very doable, without the worries that I have about the furling system.

It has jammed on me as the wind has come up, and I have been unable to roll it in. In that case I have to pull the sail down, which is not fun when it is starting to blow and I have the full 150 out and am trying to yank on it to pull it down. If it was jammed and not all the way out, I would be in a not-so-good situation. I am concerned about going further off shore with this system (like the Clearwater to Key West Race I am contemplating). I removed the furlex cover, which has eliminated all the binding so far. My other concern is that the sail shape when partially rolled up is not great, and the clew ends up higher than I would like. When it is blowing, I want the clew lower to help lower the center of effort (I think that is the term I am looking for). I have been considering the ATN gale sale, as the boat sails well with just a bit of headsail, I would probably be better off furling the whole thing and hoisting this over the rolled up sail. This would reduce wear on the 150, and probably make us heel a bit less.

So there is my $.02, 98% of the time it is great, and the price was right. Maybe others that have a similar size boat, that sails in similar conditions can give you a more accurate response for your needs.
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Old 27-02-2006, 15:44   #4
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Part of this discussion has to do with the size of the "headsail". A Genoa is just a big jib. Typically, you would call you largest headsail the "jenny" or "genny". I believe it should actually be a 130 or larger to be a jenny, but no one will measure. What you need to know about you particular boat is how big a jib you really need. Example - my Bristol 35.5 is a little tender and easily driven. It does not need a 150 or even 130. True I may suffer a little in light wind, but I have a genniker for reaching so we are really only losing some speed (1/2 knot) when flying even a 110 and trying to go upwind. My point is, many that have a huge genoa do not need it. It is hard to handle and (here's your part) can only be roller furled perhaps 30% before losing shape which means losing it's ability to sail. You want a sail that meets the majority of your needs and can still be effectively reefed, keep windage and loads down. While I am not sure what you have for a furler, most (even old ones) will allow to to reduce sail. any sail in reasonable condition can be modified to work with your furler. Any sail loft can recommend the size of jenny that will work best on your specific boat.

Keep the questions coming and don't bother with the apology. We all keep learning.
That's the purpose of this board.

Larry
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Old 27-02-2006, 19:00   #5
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Why doesn't everyone just buy huge genoas?

Cub,

Peter gives the best answer regarding the mechinism of potential damage, which is the primary concern in your post.

I would only add a tangent: possible damage aside for a moment, the application is simple mathmetics: 75% of a 120 leaves 90% of the foretraingle filled; 75% of a 135 leaves 101%; the same percentage of a 150 leaves ~112% filled. A 120, a 135 or a 150 each gives a different range of usefulness.

The day a furler/genoa combination is invented that allows the sail to be rolled up and rolled out to an infinitely varying size while retaining great shape, everyone will buy 150s and huge lappers and just roll out as much sail as desired. For now, that reality is over the horizon, so a compromise is necessary, unless you're a purist who wrestles hanked-on sails on a pitching foredeck because anything less just wouldn't be proper seamanship. BTW: more power to them.

The only breakthrough after that will be a miracle material that is light enough for a zephyr to lift and fill, but strong enough to use as a storm sail, on that roller.
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Old 27-02-2006, 19:14   #6
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First, I think 120 is plenty of headsail, 135 would be the max I would consider on my boat. My Challenger actually sails better with a high cut 120 than a 135 sweeper.
Of course the big question is about reefing. Consider this, how much of an issue (on a cruising boat) is sail shape if you are reefed to 75% or less. If you are reefing the sails to this degree, generating power from the sails is far less of an issue than keeping them balanced. I am a fan of roller reefing, and structural issues aside, I a fine with loosing a little sail shape in 30 kts of wind.
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Old 27-02-2006, 19:15   #7
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Jeff.

I love your idea!!

I'm surprised nobody captialized on that idea yet?
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Old 28-02-2006, 07:24   #8
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Quote:
CaptainK once whispered in the wind:
Jeff.

I love your idea!!

I'm surprised nobody captialized on that idea yet?

But even I as a totaly newbie would say that it would be the most expensive piece of PVC piping in existence!



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Old 28-02-2006, 11:13   #9
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Quote:
MaineCub once whispered in the wind:
But even I as a totaly newbie would say that it would be the most expensive piece of PVC piping in existence!
You have to forgive my sudden jump to find out what CaptainJeff & Kai Nui were actually talking about. I had somewhat of an idea. But due to my inexperience in actual sailing a boat. I also at the same time didn't know what they were talking about.

It just sounded to me like a good idea. And I kept seeing $$$$ signs in front of me. Also this general piece of equipment is also very expensive. And I jumped on this conversation with out not looking into all the true specifics!!

Also MaineCub. I would never suggest PVC pipe for what you were suggestioning. Not strong enough!! Unless reinforced in some way? There might be a possibility?
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Old 28-02-2006, 11:30   #10
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Question oh great ones?? How is the % of Genoa size derived. Like when you guy's call it 130% 150% and so on.
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Old 28-02-2006, 11:47   #11
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Quick answer re. the % rating of the sail. It is the% of the J measurement(distance from the mast to the tack for the jib.
If that distance is 10' a 150% jib would have a foot length of 15' and a 135%jib would have a foot of 13.5'

On our boat we have a roller furler 135%. It is a good sail for average winds. It can be furled a little, down to maybe 110%. We also have two other sails that will go up the furler groove, a 100% and a 150%

The 100 is our heavy air jib. It is made of heavier cloth and pulls much better than to 135% when it is furled down.

The 150% is our light air sail. It is made of very light cloth and does not have the heavy sun screen sewed into the leech and foot. It will set when the heavier 135 will collapse.

Problem is changing the sails. With a luff wire instead of a hank on sails hanks, when you pull the sail down it is not connected to anything. It can get away from you. Very easy to change at the mooring but harder while out there. I make sail ties ready before the sail comes down and they are attached to the life stantions.

A rollerfurling jib is a pleasure to us. It is not the perfect sail as everything on board is a compromise.
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Old 28-02-2006, 11:59   #12
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The % given refers to the foretriangle, if I am not mistaken.

The triangle created between the mast and the fore stay. I believe a working jib is typically considered a 95% or 100%, as it will fill up the entire area of that triangle.

The 150% overlaps the main by 50% of the foretriangle area.

This is how I understand it, someone please correct me if I am mistaken.
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Old 28-02-2006, 13:40   #13
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The luff is the leading edge of the sail. The leech is the trailing edge. The foot is the bottom edge.
‘J’ is measured from the intersection of the deck and headstay to the front side of the mast.
‘LP’ or 'LPG' (Luff Perpendicular) is the perpendicular distance from the luff to the clew. The ‘LP’ defines the sail size in terms of percentage increase beyond the ‘J’ measurement.
Hence, a 150% Headsail has a Luff Perpendicular (LP, or LPG in the referenced diagram) that measures 150% of the “J”measurement.

Headsail % = (LP / J) x 100

Number ~ Sail Size ~ LP[/i]
#1 ~ 155% ~ J + 55% (LP = 1.5 x J)
#2 ~ 135% ~ J + 35% (LP = 1.35 x J)
#3 ~ 115% ~ J +15% (LP = 1.15 x J)
100% ~ = J

Goto Measurement Diagram: http://cruisersforum.com/photopost//...php?photo=1764
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Old 28-02-2006, 13:46   #14
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FlaSail, I think your understanding is correct.

I taught sailing classes on a Capri-37 with a double-grooved rod headstay and a roller furl setup on a fairly old 135% (I guess, more or less) high-cut-foot genny. It reefed pretty nicely at any stage, right down to a "handkerchief". The main had only one rigged jiffy-reef point, so the jib had to be flexible. It balanced nicely as you adjusted the traveler, and the sail shape was acceptable if not perfect. It may have actually helped that the leech was fairly blown out. Kai Nui's right, in really heavy air, balance is more important than perfect sail shape.

You need plenty of jib track, too, as you move the car forward adjust the lead for the shrinking jib.
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Old 28-02-2006, 16:00   #15
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Area

Waht Gord is saying. A 150 is 50% larger than a 100, which is the area of the fore triangle. You measure the LP as Gord said and you also calculate the area. Depending on the track you have on the boat a large overlapping sail may have a low clue or a high clue. A high clue makes it easier to see where you are going, but the track needs to be longer. Off shore sails may have higher clues so they do not catch the waves. Wednesday night race sails may have lower clues to catch more wind.
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