Standing Rigging: Spectra vs. Vectran

[Garth]

Hi Everybody,

I'm new to this forum, so I thought I'd introduce myself. My name is Garth Jones - I grew up sailing in Kansas (it CAN be done!) and now I'm living in Pittsburgh and building my first boat. It's a Ness Yawl (Iain Oughtred design) named Goldberry, and she's well along. If you would like to see what I'm up to, the web site is: http://www.slaughterhousegallery.com...awl/NYHome.htm

I had always planned on using wire rope for standing rigging because that was what I knew. However, a few months ago, I happened to meet Brion (hi Brion!) and he suggested vectran. However, from what I've read, vectran loses much of its strength if bent at any kind of sharp angle. The eyes at the masthead will have a bend in them, so I'm a bit concerned. Again, from what I've read, spectra is much stronger than wire, stretches about the same as wire (1.4% under 30% load, I think), and doesn't suffer so much from bends. The rig on my boat is light and the stays do not really need to be pretensioned, so the loads should not be very high. The plans call for 1/8" wire - could 1/4" spectra work just as well or should I stick to vectran? Any advice or thoughts would be very welcome.

Thanks in advance,
Garth

PS I am a novice rigger (obviously!) and I don't quite have one boat under my belt, but I've been building furniture professionally for some years now, so if anybody has any woodworking questions, I'll happily trade info.

3/16" vectran or spectra would be fine, just use nice heavy duty welded thimbles to revent the eye from being too sharp a bend
have fun

[Brion Toss]

Hi Garth,
First, where did you read about Vectran's being particularly susceptible to sharp bends? All HM rope likes a healthy radius, but Vectran is, to my knowledge, less cocerned with bends than, say, Kevlar. If you look at the strength of 1/8" 1x19 (is this what was spec'd, or did they say 7x19?), you'll see a break strength of about 2,100lbs; 1/8" Vectran ó just the core, mind you ó rates at 1,900, so it is very likely just fine for your boat (the next larger size is up over 4,000). Some Spectra's actually rate at 2,100lbs for 1/8", but you are likely to exprerience "creep" with them.
Back to those sharp bends, where might they be? Neither bolsters nor eye throats should have them, assuming the eye is sufficiently large (see "Apprentice")
Be in touch on all this.
Fair leads,
Brion

[Garth]

Hi Brion,

Tara recalls that you actually told us that vectran doesn't care for sharp bends when we back in Friday Harbor. But maybe we had a different underdstanding of 'sharp bend.' Regardless, the only bend issue is at the masthead. Based on Oughtred's plan each stay has an eye that goes around the masthead - I suppose if those eyes are big enough there won't be much of a bend. Oughtred's drawings show a tight eye around the masthead with a pretty sharp bend as the stay goes down to the boat. The other end is an eyesplice around a deadeye, so that should be no problem.

The plans call only for 1/8" flexible wire - no idea if it should be 1x19 or 7x19. Regardless, I was thinking of using 1/4" line for the stays because it ought to be easier to work with (I'm good with wood, rope not so much, at least not yet!). I realize that in terms of strength, that's overkill.

Cheers,
Garth

[osteoderm]

I used 5mm Yale Maxibraid (singlebraid spectra) for the lowers, uppers, and runningbacks on my 13' LOA gaff cutter with great success. I served the large softeyes at the mast attachments, as well as served the small eyes around generous thimbles alow. Great stuff; light, cheap, strong, straight-forward to splice (Mobius Brummels courtesy of the Apprentice). The service was done with waxed nylon twine, including a patch at the spreader tips. Can't say I've noticed any of the creep that Yale warns (online) may occur, but then again, my loads are pretty low. I get more stretch out of my (frequently adjusted) seine-twine lanyards.
Only real worry of mine is concerning chafe from the jibsheets on the uppers; I've been keeping an eye on them, and will likely just replace them entirely if they get to looking fuzzy, rather than play around with more service, baggwrinkle, shroud rollers, etc.

[Brion Toss]

Hi again,
HM fibers, in general, can tolerate bends less than twice the rope diameter; for the tight angly you are talking about ó from more-or-less-horizontal soft eye to shroud angle ó all you need is a radiused shoulder. But I'd go further and, with wire or HM rope, open up that eye a bit, so it's not pulling too hard laterally on the throat of the splice. If the eye is resting on a shoulder, you might need to mold in some thumb cleats.
Fair leads,
Brion

P.S.
Just spent a weekend at one of Mr. Saotome's weapons seminars. That man knows how to hold a sword.

[Garth]

Hi Everybody,

Thanks for the advice. Per Brion's original suggestion we've gone ahead and ordered vectran cored line (NE Ropes V-100).

Brion - I've added thumb cleats to the mast head that are generously rounded over in all ways that matter. We'll make the eyes large enough to lay straighter on the mast and so we should be in good shape.

A few more coats of varnish on the spars and a couple of weeks of warmer weather to finish the hull and I'll be going sailing!

Thanks for all your help.

Garth