Hi All

I'm deciding whether to use Dyform wire or 1x19 wire for my shrouds, forestay etc.. I realise the dyform is stronger, and therefore more expensive (1x19 = $2 per/m) (dyform $4.50 per/m), but for something that you would replace every, say season/year, is dyform really necessary? On every boat i've ever owned, i've never broken a 1x19 wire, but I am rigging a boat with greater loads (T4.9 cat rigged)

Regards

I've done the math on this topic and discussed it with Greg Goodall (AHPC) himself.

3 mm dyform on the standing rigging is fully depenable.

3 mm 1x19 is pushing it a bit, Greg said any less thickness or several loose strands; you will break it.

In my math it turned out that the forestay is by far most heavily loaded. Moreso the sidestays. Think roughly 600 kg versus 450 kg. This means that a 3 mm 1x19 (break = 720 kg) could be used for the sidestays with a 50-60 % safety margin. This may sound like alot but is minimal in conventional structural engineering. The forestay and bridles must then either be 4 mm 1x19 (1285 kg) or 3 mm dyform (920 kg), given safety margins of respectively : 215 % and 153 %

If you are singlehanding then you may risk using 3 mm 1x19 for the forestay and bridles as you will be running with less mainsheet loading here.

Personally I never change standing rigging every year or season. On all my boats I used the standing rigging for 5 years or more. On my F16 (modified Taipan) I have now been sailing with 4 mm 1x19 rigging for over 2 seasons.

Greg mentioned to me that they have run older imperial 3 mm 1x19 wires on their earlier boats and that held up well. But it must be remembered that these wires were actually a little larger then 3 mm in diameter. More something like 3.2 mm. You can't this wire anymore and METRIC 3 mm 1x19 wire has a lower break strength then these older versions. I know a few Taipan sailor still using this older wires for several years now.

So in summary, consider METRIC 3 mm 1x19 as the absolute smallest safe diameter. To be really safe opt for 4 mm 1x19 or 3 mm dyform. If you opt for 3 mm 1x19 make sure you inspect your rigging often and thoroughly. If you can find some older EMPIRIAL 3 mm 1x19 (3.2 mm) then consider yourself lucky and go for that.

I hope this helps

Wouter

Consider also Erik Precourt's textile rigging:

www.precourt.ca

I've got 'em on the Fboat, and have priced for the 18Sq, and the price was comparable to Dyform. They're like WAY light, are working great on the Fboat, and, well, they're just kewl.

Something else to consider, dyform is high quality wire. It's lot tested and there is a materials cert. You are a lot less likely to get a "bad lot" than with generic 1x19.

When you are looking at fabric or synthetic rigging remember to look at the stretch. Compared to wire of the same strength, synthetic has a huge amount of stretch. I ended up having to size the rigging for stretch rather than strength. On the bright side, it's real easy to recycle if you don't like it.

I am about to make some shrouds up out of 4.5 or 5mm dyform an older lot I found on sale .My question is can there be to thick a wire and is this particular wire still ok for my Tornado
thanx .

The only problem that I could see would be if the wire required larger terminations or connectors that didn't work in your current fittings.

sm

"to thick a wire" or not to thick a wire:
THAT, is the question.

GARY

5M dyform sounds like overkill, I wouldnt want that much weight up in the rig.

Gary, are you slinging some arrows?

Thanks for the replies everyone ,I am asking because this is only a guess if you were out in a heavy gust situation I would rather the shroud go before the mast .It is for an Tornado classic so it already is kind of heavy anyway
thanks again

Gosh no I am not slinging arrows. I was clowning around.

By the way, I suppose that one can save as much windage by eliminating vinyl coating on one's wires than the windage saved by switching to die-form wires.

GARY

Aircraft Spruce & Specialty lists their 5/32" (4mm) 1 X 19 stainless wire rope at $.85/foot or $2.78/m. Their 1/8" (3.175mm)lists at $.62/foot or $2.03/m. This wire is approved for installation on type certified aircraft so you can bet your a$$ it is high quality wire. They issue a certificate of conformance with each lot purchased.

From their website:
"The major difference between aircraft and commercial cable is the lubrication applied to aircraft cable, which provides substantially better fatigue life than non-lubricated commercial cable. Aircraft cable requires extensive extra testing, documentation and certification to meet military specifications. Aircraft Spruce obtains its aircraft cable from domestic sources and the cable is certified to MIL-DTL-83420 and QPL Certified."

http://www.aircraftspruce.com/catalog/appages/controlcable.php

Jimbo

He is just taking "arms against a sea of troubles" <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Matt, give Syney Rigging a call, Bruce or Gardo can make a se of Dyneema or Vectran stays with the precourt end fittings and you will have the lightest rigging by far, it is also stronger then both the dyform and the std wire.02 95554277

Thanks Macca

But (theres always a but) I have just arranged for dyform wires. But next time (theres always a next time) I'll look a bit closer at that. But thanks anyway.

Regards

Its interesting to note that the Acat crowd has all gone away from synthetic rigging and settled on dyform for rigging and diamond wires. The concensus was windage was to great with synthetic rigging because of the cover that they put on it.

I put Aramid rigging on my HT and it was 2x plus in cost vs dyform wire. I dont think I'd do that again. The windage (perceived perhaps) plus the cost, plus the Aramid needs to be stretch tested every year, if water gets in the cover it can rot, so they recommend year stretch testing. With wire you can visually inspect for wear or rust. Wire (dyform) wins in my book.

Bill

Don't you have to be incredibly careful with handling dyform?
1x19 seems to accept all sorts of abuse while rigging/derigging/transporting etc. but I've heard it said by some half-boat sailors that they have to be constantly vigilant with wire rigging that it doesn't get caught under or around something or kinked otherwise it's scrap....

We have dyform on the Tornado, and it's no worse than regular 1x19. We are always on the alert when rigging tough, nobody are allowed to step on any wire or rope! Both Frode (crew) and I used to do a lot of climbing, and it's a big no-no to step on any ropes there, a good habit we brought with us.
One of the disadvantages of dyform is that you need terminals on the end of the wire. These are impossible to inspect without proper equipment (hmmm, perhaps I should try to do some x-rays of them? Wonder what exposure time you will need..).
You will probably have a better chance to see if the swaging on a 1x19 is about to give way. If the rigger put on two swages your are even better off. Most of the Tornado shrouds I have seen give way have broken inside the terminal, where it has corroded.

Myself, I would like to try synthetic shrouds once. But not with covers, and I would like to use wire where the shrouds bend around the mast.

Another good low-cost source (in the US anyway) is Bosunsupplies at http://www.bosunsupplies.com

I've read on one suppliers website that the dyform has been approved for use with thimble/swage ends.

This would mean the best of both worlds, one its stronger and two you can see all the wire.

Regards