Warpspeed Dyneema by Samson
 

Would this be a suitable HM line for standing rigging? I like that it has a polyester cover to keep the sun off of the Dyneema, and it's less expensive than comparably strong SS wire.
Thanks,
Ben

depends on the boat, but I'd say NO.
dyneema creeps, and this means keeping a tune is a problem

what kinda boat ?

check out the prestretched dyneema called Dynex Dux, or if you want a cover on it anyway then use vectran for standing rigging

we have been doing vectran with fine results.

cheers

Thanks, Brian. I'll have a look at Vectran.
How much does Dyneema creep? Is it just the tiniest bit? And does it ever stop creeping? I could deal with constant tuning until creep stopped, it it ever were to. Also, at what percent of breaking load does creep begin? Could creep be mitigated by oversizing?
The boat is a Cape George 31 pilot cutter I'm finishing from a bare hull; I'm putting a gaff rig on it rather than a marconi.
Ben

Thanks, Brian. I'll have a look at Vectran.
How much does Dyneema creep? Is it just the tiniest bit? And does it ever stop creeping?
Creep varies with load and manufacture of line - but it is not the tiniest bit, its a lot. For instance on runners one size up for a Tayana 55 (3/8" amsteel) they elongate 6" a year, each year (we keep shorteing them, three times now- this fall they will get changed to Dynex Dux which is prestretched so shouldn't creep as much)

Could creep be mitigated by oversizing? Yes , it sure can, but it always creeps, just less at lower percent of load. That is how we deal with the problem when using the Dynex Dux, oversize stuff a bit.

The boat is a Cape George 31 pilot cutter I'm finishing from a bare hull; I'm putting a gaff rig on it rather than a marconi. IF its to be gaff rigged, keel stepped and set up with deadeyes, then Dyneema will likely be fine, as these rigs get a large protion of their strength from the bury in the deck (depending on design) and so shourds that get abit slack wont be the worst thing - I have yet to sail on a gaffer that doesn't have slack rigging on the lee side when loaded up.

Check out the Hampjeden website, and Colligo Marine, and Precourt Marine for more info, or give BRION TOSS a call

more about the rig design will help give you better advice. do you have a drawing ?

Please excuse and correct my ignorance but cost aside what advantages are there to using rope instead of wire for the standing rigging on a boat like this? Am I wrong in thinking that wire has lower stretch...or at least settles more effectively and is more abrasion and UV resistant than Dyneema or Vectran? The strengths are similar in terms of similar diameter so windage would be similar, yes?

I ask because having used a lot of 6X19 IWRC 1/4", 3/8" and 1/2" wire, variations on the spectra theme and miles of 1/2" double braid in non-marine applications rope of any sort seems a less durable long term solution than wire in a static system. The main advantages of cordage over wire for me have always been either lower cost or lower weight. Often the lower cost is a fair trade-off well within safety margins. Sometimes the lower weight is essential to a safe system in terms of installation and use. The relatively minuscule amount of material used in the standing rigging of a small boat make the cost a non-issue in my mind.
What am I missing...is is weight?
Am I wrongly prejudiced?

Brian,

That's a lot of creep, all right. I've spoken to Hampidjan about Dynex Dux, and I like that they're amenable to customizing covers and whatnot, but their prices are less....reasonable than what I can get through Port Supply, which carries Warpspeed and Vectran at good (for me) prices. I've already consulted with Brion about the rig, as well as having Carl Chamberlin, who deigned the Marconi rig for that boat, say that if he had a CG31, he'd gaff-rig it too. So I'm fairly confident in the design I have. I'd post a copy of the plans if I could, but I'm woefully incomtetent with computer stuff (I can barely pull off logging on to this forum).
And Jeff,
Rope is just another of the options I'm considering, along with SS wire and Galvanised wire, for the rig. Weighing the options, as it were. Though SS wire costs roughly the same as HM rope, there's then the problem of terminals; the swageless ones are expensive, and the splicing of wire, SS or galvanised, is daunting to me. But rope can be spliced with incredible ease, and it can be spliced in the midst of bad weather, without the need of a special vise, and spare rope stores easily, and a spare HM shroud can be set up within hours, anywhere in the world, if necessary. And while I like the precourt deadeyes, those too are terribly expensive, compared to the nice domestic galvanised turnbuckles I can get for $25 at the hardware store. While I'm not rejecting any rig options right now, I'm trying to get all my ducks in a row so I can make the best and most responsible decision.
Best,
Ben

All that makes sense. I'm in a similar position where I should be weighing options perhaps more thoroughly than I have. I'm planning to fundamentally keep the existing gaff rig on the pinky schooner I just got and am also planing to splice the wire for it. The utilitarian galvanized wire and hardware I'm most familiar with seems to make sense for a PacNW cruiser. You raise some good points though that I'm going to give some thought to.

Here's a question: If creeping is the main drawback to cordage in standing rigging what about whipped eyes that could be easily cut apart and redone to shorten the lines? Anyone have destruction test results of whipped eyes in line like this? A splice is stronger but is whipping strong enough to stay within a reasonable safety factor? Or would you just use a finger trap type splice and bury some more tail to shorten?

for low cost (but very safe) workboat style stuff we have been using vectran stay , served over, spliced around stainless thimbles, into galv turnbuckles. Just make sure you buy turnbuckles with a load rating stamped on them, and that it is suitable for your boat. of course making your own deadeyes of wood would be even cheaper i;d think (if the wood was free)

I wouldn't do dyneema with turnbuckles, they don't have enough travel, youd be resplicing all the time...
vectran works fine though

Hi Jeff,

Not sure whipping (seizing, really) HM line would be a good idea; it doesn't take kindly to the squeezing loads of knots, and a seizing is just basically squeezing the two parts together. But a 12-strand splice is easy to pull out and shorten, though I'm more keen on Brian D's Vectran in order to avoid having to do that a lot. My biggest worry with Galvanised is the difficulty in finding a domestic wire that's cheap enough; it seems most of the Galvi stuff is coming from overseas, and what's made here, (when you can find it), is terribly expensive. Maybe I haven't looked hard enough yet.
I'd love to make my own deadeyes, but by the time you buy the right hardwood (would cocobolo suit, by the way?) and put all the time into it, you may as well have bought Precourt. Sigh....

Thanks...I'm getting some food for thought here. I agree with you about offshore manufactured rigging components of any sort and when presented with them on a job will do a shoulder check and "retire" that crap before it can kill someone. What size and construction of galvanized wire would you be comfortable using? How much would you need for your rig? I'm going to have to source some for my boat. I'm going to start doing that next week when I have to talk to suppliers for a little movie job I gotta do. You in the PacNW?