Triradial cut sails

[Windfall]

Well we've sorted out the new mainsail (thanks to everyone who answered)...so now the genoa.

What's the advantage (if any) of a tri-radial cut furling geona over a cross cut? The price dif. is not too horrendous so we're considering splashing out, but don't really have the first clue about it.

Looking forward to lots of helpful advice.

Cheers
Sharon (looking forward to when the spending can stop!)


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[jimi]

<A target="_blank" HREF=http://www.ybw.com/cgi-bin/forums/showthreaded.pl?Cat=&Board=ym&Number=300574&page=&view=&sb=&o=&vc=1#Post300574>have a look at</A>

I went the triradial route and am very pleased

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[oldestgit]

Jimi:

Your link "have a look at" seems to wind up in a blank page.... am I drinking the wrong stuff ??? or should I get a different gas supplier for this computer.........



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[ccscott49]

I have bi-radial yankee and staysail, very good, with the cloth stretch/weave/weft etc. in the right directions, I guess tri-radial is just that little better.

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[oldsaltoz]

link works just fine for me Jimi, perhaps a change of gas is required, it's the results from a search.

<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[Windfall]

oops - next time I'll try and remember to do a search first.

We will speak to Kemps on Monday & see what they reckon.

We don't race, but she's a quick boat so it seems churlish not to at least try and get the max. out of her.

Sharon

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[oldestgit]

The link worked this morning ... Must have put a shilling in the gas meeter.

A good link and excellent food for thought.

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[charles_reed]

I used to have a 140% triradial roller genoa but, on the advice of my sailmaker reverted back to a 150% crosscut genoa.

The theory behind the triradial is great and for the first 18 months of it's life it certainly sets better than a crosscut genoa.
However, from then on it's downhill, and after about 4 - 5 years of use you'll need to replace it, whilst the crosscut will still be soldiering on.

It's horses for courses - if you are a weekend sailor with pretensions to racing then the triradial makes some sense - though a laminate sail has a better performance and comparable length of life. If you're a serious cruising man doing 3000 - 4000 miles a year then go for the crosscut with an ample foam luff.
The solent is, in any case crosscut.

For yankee cut sails the situation is entirely different - my working jib/No 3 is a radial cut.

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[pwfl]

what no one seems to have mentioned so far is the shape when partially furled.

the answer seemed to be (having been in the same position as you a while ago), that the radial sail will have a slightly better shape when fully unfurled, and, most importantly, has the panels aligned with the stresses in the sail, so it should maintain that shape longer (again, when fully unfurled).

all reasonably intuitive really.

the only thing is, the whole concept kind of breaks down a bit once the sail is partially furled, in which case (again, quite easy to visualise), the cross cut sail should have a better shape.

i`m certainly quite happy with my crosscut sail, & i would guess most cruisers probably would be too.

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[vyv_cox]

You've beaten me to it. When unreefed there may be a slight advantage to the tri-radial in terms of fair loading, as the highest loads are along the weave. Thus its life might be expected to be extended in comparison with cross-cut. As soon as the sail is reefed, the loads become very unfair on a tri-radial and the sail will stretch at the luff. In a few years it will be baggy and the boat will not point. By contast, the main direction of tension on a cross-cut is always with the weave, with lesser pull across the weave of the cloth, not the best possible but acceptable. Where the picture has changed is with the new cloths, such as Hood's Vectran. This is very stable across the weave and a cross-cut genoa in Vectran should outlive almost anything else. The original Chay Blyth British Steel boats had Vectran sails and Hood could find no deterioration after the race.

There may be slightly more deterioration of Vectran in UV (I have read various views on this) but we are religious about covering mainsail immediately sailing has ceased and we ensure that the UV strip on the genoa is in good condition and rolled correctly.

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