Westsail Owners Alliance - Thread: "Another Asymmetric Spinnaker Question!"
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Thread: "Another Asymmetric Spinnaker Question!"

12,268 posts on 2,444 threads   •   From Mar 07, 2004 - Jan 08, 2012

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Another Asymmetric Spinnaker Question!


Aaron Norlund

Hi all,

What is the optimum size of a cruising spinnaker for W32s? I've found many threads on here about them, but haven't seen a square footage recommendation.

Bud, do you have dimensions perhaps?

A good friends is giving my a new 580 sq/ft FX asymm still sealed in its original packaging, so I don't want to pop it just to find it's used and ruin its pristine retail value. I has a 44' luff.

On that note, I think a catalog of sail dimensions would be a great addition to the members section of this site.

Thanks for your time!

Fair leads and shady quarters,
Aaron N.


Bud Taplin
(Member)

There is a W32 sailplan with dimensions in my Westsail Service Manual. Page A-24


Rich Morpurgo
(Member)

mine has a 44 foot luff and works great.

rich


underpinaker


Aaron Norlund

Boy, everything is in your service manual. There's so much, I forget what's there!

Fair leads,
Aaron N.


Aaron Norlund

Bud,

I just had my father look and he says he's unable to find numbers for an asymmetric in our book. Further, most of the labels are fuzzy and illegible, so he's not able to makeout the specs on any of them.

Thanks for your help!
Aaron N.


Dave King
(Member)

Ahoy Aaron,
I don't know the answer to your cruising spinnaker question because I don't have one. I do have some numbers that may be helpful however.
I have 2 tri-radials that are both 168%. Remember that 180% is a "regular" spinnaker for non-bowspritted boats, but this number doesn't work too well on a bowspritted boat. My spinnakers measure 1157 sq ft.
The formula for cruising chutes is slightly different due to the narrower head, angled foot, and flatter cut. Assuming a 150% for the cruising chute, the area would be 861 sq ft.
Your friends 580 Sq ft chute would certainly work, and price is a big determinant, but it will be smaller than you could use.
Good luck, Dave


David Wiencke

Hi all,
I would like to continue this asymmetrical spinnaker/drifter question. I'm looking at a used asym. spinnaker; 45' luff, 36' foot, 36' leech, 3/4oz, reportedly 1,200sq.ft. I figure this could be as big as could fit on a W32, maybe too big, but at the right price could be recut to fit.

Does anyone have luff, foot and leech dimensions of drifters/asyms they've used on W32's. I find that the sail area comparison is not very helpful when looking at used sails, ie; Bacon sells their used sails by simply listing luff, foot and leech dimensions, which makes it fairly easy to determine if a sail is likely to fit. If unsure, they suggest tying lines together to match the dimensions of the sail one is interested in, and doing a test hoist. Being out of the water for the winter, I can't test the fit.

I have a hank-on genoa with 41' luff, 26' foot, and 39' leech. We use this on all points of sail in light air, but it needs a bit more pressure when going downwind. I'ld like a lighter, larger (as large as will fit) sail for off-the-wind, by itself, or evan combined with the jenny poled out on the other side.







Aaron Norlund

David,

The asymmetric I use has a 43' luff, and I don't think I could get much more on there. I can just barely get the luff tight as it is! So I doubt a 45' luff would work on anything above a broad reach; you wouldn't be able to get the luff tight enough. But it's fairly inexpensive to have a sail recut up there.

Keep your eye on ebay as I've seen four or five asymms over just the past couple of weeks with the right length luffs.

As for dimensions; I think with asymmetrics, you only need to know the luff, sail area, and cloth weight. If it's 950 sq/ft and has a 43' luff, it'll probably work. The leech/foot is going to be fairly consistently in proportion, with the leech of the asymm always being shorter than the luff, but longer than the foot. The cloth weight is usually a good indicator of the belly cut of the sail. A .75oz chute will have a bigger belly and likely only be good up through a beam reach; 1.5oz will probably be flatter and able to carry a bit more to windward, and in higher winds.

If you have a big genoa, I'd go for a .75oz sail as you'll use the genny when going to windward for it's better shape.

Just don't get something with a longer foot than your boat! If you want, I can measure my asymmetric some time; I don't know the foot/leech measurements. But it has a 43' luff and is right about 950 sq/ft.

Cheers!
Aaron N.


David Wiencke

Hi Aaron,
Thanks for the response. At the top of this thread you stated that your spinnaker had a 43' luff and sail area of 650sq'. Now you say 950sq'. How can you calulate the sail area without also knowing the foot and leech measurements?

Looking at Rich's photo above, he says he has a 44' luff and the tack appears to easily clear the bow pulpit.

When I'm looking at the foot measurement, I'm allowing that the bowsprit adds about 6' and the boomkin adds another 2-3' to the length of the boat. Since I have a fairly large genoa, I would be getting a spinnaker primarily for off-the-wind sailing. As you might guess, I really don't like using the motor.

In another thread, http://www.westsail.org/discus/messages/24/567.html, Eva Moresco asked about a 44'8" luffed drifter. I wonder if she ever tried that sail? I couldn't find an email for her.


Aaron Norlund

David,

I didn't update my first post. I sold the little asymm and bought a used fully symmetric 1050 sq/ft sail from another W32 owner. This was recut by a local loft to be a 950 sq/ft asymmetric spinnaker, with a 43' luff.

In addition, I use my sail with a sock, and the head linkage adds about a foot, so it essentially has a 44' luff. As I said, I can just barely get its luff tight, and I would like another 6"-12" to enable a tighter luff. This would let the sail carry a touch above beam reach, whereas now I don't feel I can creep anywhere above ~95 degrees apparent.

In the photo of Rich's boat, it looks like he's on a broad reach, and the luff is fairly slack, so that probably explains why the tack is so high. I imagine he can just get the luff tight, and perhaps not even so. He'll probably chime in on that. But, it seems very common for people to carry asymmetric spinnakers with too long of luffs, making them nearly strictly broad reach or greater sails, when a good asymm has the potential to be used going to windward if you can get the luff tight enough.

I prefer asymmetric sails to carry their area using foot/leech, rather than making the luff longer, but there are tons of people who've sailed more than me who have sails with longer luffs than actually fit, so who knows. Just my preference.

Cheers!
Aaron N.


David Wiencke

Hi all,
Just got back from a weekend sailing and got to fly my new/used 47' luff "A scow" asym. spinnaker a few times. I think the foot measurement was 29', I don't recall the leech measurement exactly, but I'm guessing 35'.

We sailed nicely wing on wing, and up to a close reach in about 8-12kt wind. When the wind gusted to about 15kts, it was getting a bit much for the close reaching. We couldn't get the luff fully stretched, but it was tight enought to get onto a close reach with apparent wind. Very happy westsailors. Here's two pics...
wing on wing
close reach

Way more power than my genoa. I would estimate the square footage of the asym at about 1000 sq.
ft.

Typical "A scow" asym spinnakers are; 47' luff, 36' leech and foot-est. 1200 sq. ft.

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