Ideal size of roller furling jib

Dec 24, 2009
60
Hi

I have a roller furling jib which is in a good shape, but its to big for me when I sail alone. Its simply to hard to get it around when I tack. The bottom part is 520cm (a little over 17´)
If you compare that with the J of the front triangle, its a 170% overlap!!
Its 21 sqm. (226 sqf)

Besides, I dont find the Vega to be specially stiff, and I need to roll it in relatively little wind. And.... as with all kinds of rolling systems, the shape of the sail gets worse, even though It has compensating foam.

So, I´m seriously considering a new one. A smaller one. But how small? My guess is something around 15,5m2 (167 sqf)

Another thing is if I really need to have compensating foam in the luff of the genua. On a smaller genua I will roll it in a lot less and honestly, I dont like sailing with the foam in the the genua. It makes it a lot more dead.

So tell me your experiences.
Anders (1118, Yggdrasil)
 
Oct 30, 2019
574
Anders - Unfortunately, I have nothing to add here...except that I don't have a furler. We replaced the furler this year with a standard forestay and I can't see ever going back. The primary benefit is that the three different sails (155, 100, 60) plus the storm jib allow me to balance the boat much better.

That said, one just can't beat the convenience of a nice roller furling jib.

Jack
 
Oct 30, 2019
1,459
Anders, That's a big sail!

I love my 120% that's 169 square feet, using 6.5 ounce Dacron.
Luff = 28.70'
Leech = 26'
Foot = 11.84'
The foot is high and does not catch water too often. Also, the 120% reefs down nicely, without a luff pad, to about 90%, or even less.

I have a nylon Genoa that snaps to the anchor roller and uses the spinnaker halyard, and it has an Amsteel luff rope so can be tensioned quite hard for pointing closer to the wind (not as close as the 120% on the furler). It's 231.7 square feet, using 1.5 ounce nylon.
Luff = 30.00'
Leech = 28.02'
Foot = 14.54'

I use the 120% jib almost exclusively, even in light winds, but will pull out the nylon monster if the conditions are right, as they were here:

Hope this helps!

Peter
#1331 'Sin Tacha'
 
Dec 24, 2009
60
Jack

If I was sailing with a crew, I would change to a standard forstay. I´m not fond of rolling sails at all. BUT, I sail 80% of the time alone, so a roller furling jib is really convenient.
I have the hope that a smaller furling genua will not need to be reefed to often and that it´ll reef better than the one I have.
Getting a smaller area of sail doesnt help if the sail when reffed has a poor shape.
 
Dec 24, 2009
60
Peter

Thats good information and its very close to what I had in mind. Luuf and leech identical (almost) but a 13,1´foot. That gives me 167sqf.

Could you please check your measurements. Because when I make a drawing uf your jib and calculate the area, I get 153 sqf and not the 169 you say.
153 is just a little bit bigger than standard jib (not genua)

I general, I feel that the vega sail well with this size of frontsail in 5- 6 knots or more. The very big genua is only usefull in very light winds or when reeching.

Anders
 
Feb 18, 2010
33
Anders,
I went through exactly the same thing as you earlier this year- in fact if you search for it you should find that I asked the same question!
I had a 150% genoa with no padding, that was well past it's best- initially I decided to get a new 120% genoa with padding, and use the bigger sail for lighter winds and downwind work.
However whilst trying out some friends' sails to get a better idea of what size to buy, I found that handling the 150% on the foredeck was an absolute nightmare! There was no way I was ever going to wrestle with it on calmer days. So I went for a 130% genoa instead, with padding. This was, incidentally, supplied by Quay Sails who were very good to deal with, were cheaper than everyone else except for 'Hong Kong Sails', and seemed to know the Vega inside out. It sets brilliantly, both full and wehn reefed, and has transformed the boat. We had it made in 'Ocean Premium Plus' which has a ripstop pattern for durability and lower stretch.
We've been out racing in 30kt winds this year and the sail works extremely well- I'm glad we didn't go for the 120% sail because we'd probably be a bit underpowered some of the time.

Rob
'Mavanier' V1583
Stornoway, Scotland
 
Oct 30, 2019
1,459
Anders,
You are correct: 153', according to a quick plot in AutoCad. My figure was taken off the printout from the sailmaker's design software. I get my sails designed and plotted onto Dacron at a local sail shop, and cut and assemble them myself. I get the measurement print out sheets too. I talked to the sailmaker just now, and he said the software has a "different" method of calculating area.

Checking the figures for sail LP and boat J lengths it calculates out to a 116% jib.

Anyway, it's one heck of a sail for the blustery Juan de Fuca Straight!

Your website address is on your blogspot, right hand side, near the bottom of the text area. That's how I found it.

Cheers,
Peter
#1331 'Sin Tacha'
 
Jun 2, 2004
128
I'm also going to chime in on the benefits of hank on sails. I converted from a roller furler about two years ago and I like the flexibility that having hanked on sails gives me. I have a genoa about 130% or so, a standard working jib, heavy weather jib of 96 ft square and a storm jib of around 50 ft square plus an asymmetrical.

I sail mostly alone and have done some long trips. You defeinetly have to plan ahead with hank on sails - always thinking about what the next change will be and have to have a good system for going forward - jack lines and a harness and solid handholds.

That being said, I have been thinking recently about adding what is known as a solent stay-its a stay just aft of the forestay and attached just below the forestay on the mast so no need for runners. The advantage as I see it is that you can then put a roller on the forestay and have the inner stay for the hanked on -raedy to hoist when you furl the big sail.

The reason I'm thinking of it is a possible single handed crossing to bermuda from the US east coast and back next summer.

Anybody have any comments?

Tom

V-398 Pagan Baby
 
Sep 24, 2008
346
I don't have a furler on my CS27 (sorry it's not a Vega) and don't regret
not having one. I think you have more flexibility but do have to work out
easy changes. The Solent stay makes sense but I would not have a furler on
either unless everything else on my wish list was fulfilled. A sail can
easily be kept along the lifelines at the ready, in stops possibly, and the
Solent stay makes it even easier to change.
 
Dec 24, 2009
60
Thanks for your reply Rob

The problem with the use of % in the size of forsails is that its never clear how its used. Is it the % of the overlap of the front triangle or is it the % of the size of the front triangle?????

I´m thinking mostly on how much sail I´ll have to drag around every time I tack. I´m used to sail boats with bigger mainsails, just a jib and I dont really like genuas. But I think that just sailing with a jib which is 13,5 sqm. (145sqf) is not enough in a lot of conditions. So what I look for is a foresail which is just big enough to get that extra drag in light winds. I will accept to go slower on downwinds. I´m 100% a cruiser nowadays. (I used to be a racer)
So can you say how many sqf or sqm your 130% genua is? Right now sails are cheap in Sweden and I´ve been given a very good offer on a 16 sqm (172sqf) genua with padding from a good sailmaker. Thats 118 % of the front triangles size. I havent been given the exact length of the the foot, but I should be around 410cm (some 13,44´) This means a a 133% genua if its the overlap that you use. Its an interesing size. Its a small genua and not a jib, bot maybe I find it to be a tad to big.

Anders
1118 Yggdrasil
Spain/Denmark
 
Feb 18, 2010
33
Anders,
I think that the percentage figures are related to area of the foretriangle... so as I understand it, a sail which came back to the mast wouldn't actually be a 100% because the height of the clew loses some area- does that make sense? I may be wrong about this.
I was never given a size in m2 for my 130% genoa, but the other quotes I received varied between 19 and 20 m2 (except one which was 17 m2 which seems far too small, I wonder if it was a mistake).

I used to have problems with tacking the big genoa around the mast; the new sail is much easier. I changed the old sheets for a new sheet in a single length, attached to the sail with a cow hitch, which helped a lot as well. Now it hardly ever catches. In light winds when there is little pressure to help blow the sail through, you can accidentally make it catch on the shrouds by hauling in on the winch too soon, but you soon learn to avoid this.

You will need to choose a size of sail based on the weather conditions you expect to find. Most people seem happy enough with 140%, but I live in a fairly exposed location and we can get a lot of strong winds (25kt is a nice day up here!) so I thought it sensible to go for a slightly smaller sail. With the 130%, I can carry the full sail until about 20kt winds, and even at 30kt I don't need to have much of it rolled away... I'm sure I could roll away a bit more to cope with even stronger winds.

Remember that the Vega is a 'foresail driven boat'- you do want to be underpowered- so I would say think carefully about the conditions you will be sailing in and choose a sail that matches them.

Good luck, and by the way your Vega looks very nice- much tidier than mine!

Rob

Mavanier V1583
Stornoway
Scotland
 
Dec 24, 2009
60
I actually think that the use of % is mostly related to the overlap. This you calculate using the lengt of the J (Forestay to mast on deck) which is 300cm on the Vega. In this case Peters genua which is 360cm on the foot will be a 120% genua just as he say himself.
Your 130% genua will be around 17m2 if you draw the length of the luff, the leech and the foot on a piece of paper and calculate the area. The 19 - 20m2 genuas are the standard 150% genuas. And my 21m2 genua is WAY to big

The Vega is more or less a forsail driven boat, I agree. Its not so extreme as IOR designs from the 70th and I find it important to use the mainsail as well when sailing. Remember that the mainsail is bigger than the standard Jib (15,5 and 13,5)
with a 120, 125 or 130% genua I will reef the main before the genua. I have slap reefs which I can reef from the cockpit.

I´m pretty sure I will say yes to the offer I got. Using overlap percentage will be 125% genua. (In other words it´ll be with a 20cm longer foot (8") than Peters) Right in between your Genua and Peters. Then we can discuss from now on to the end of the world which is the best. Hehe.

Wind conditions in Scandinavia vary a lot. This summer I had lots of light wind and no wind. But I also had to tack against 30 - 35knots and 2 knots of current on an occasion, and then my 170% genua when its rolled in to something of an acceptable size has such a bad shape that it reminds me more of an old sack than a sail.
As a cruiser, I´m trying not to think how much wind I can handle with a certain amount of sail. I´m thinking mostly of balancing the boat and use as little sail as possible. Its much less tiring than the other way round and I prefer to reach harbour half an hour later and fresh and capable of enjoying the rest of the day.

I dont think the Vega needs a lot of sail in order to sail well, but it needs a certain amount of foresail if you are going agains a lot of waves.

Anders
1118 Yggdrasil