Standing rigging DM20 vs SK78?

[andreas.mehlin]

SK78 seems still to be the most common dyneema, although the DM20 has no creep but less strength. A 8mm SK78 can take 7000kg, but a DM20 5000kg.

One option would be to go with a 10mm SK78 instead and the creep would be less. It would also give more strength..and more shaft protection.but with a heavier and more windage due larger size.

DM20 is more expensive...

What do you guys say?

[Benz]

DM20 was designed for standing rigging. That'll be my next upgrade. 78 still creeps, even when pre-stretched. Why not split the difference and use 9mm DM20?

There is also prestretched sk99; Marlow calls it MAX 99. Strongest Dyneema, and it'll creep less than the same diameter of 78 because it'll be further from breaking load.

Probably expensive too....

[odonnellryan]

I'm replacing rigging on my cutter this winter. What's the benefits of Dyneema to stainless in y'all's opinion?

[andreas.mehlin]

Originally Posted by odonnellryan

I'm replacing rigging on my cutter this winter. What's the benefits of Dyneema to stainless in y'all's opinion?

1) Less weight aloft
2) Very easy to work with dyneema
3) Very easy to carry extra dyneema onboard incase of need of replacement
4) Easy to inspect

[Otia]

Originally Posted by andreas.mehlin

1) Less weight aloft
2) Very easy to work with dyneema
3) Very easy to carry extra dyneema onboard incase of need of replacement
4) Easy to inspect

the weight savings are way above the center of gravity, so the righting moment is improved; if you're a bluewater cruiser that should concern you.

also costs much less

[odonnellryan]

Sure on the cost? I've tried to look for some US suppliers and it seems like I'm seeing numbers around $3.5K+ for same length of line that would cost me $1,200 in steel. Over twice as much: hardware would cost me something for the wire but not that much.

Not being negative, there doesn't seem to be very much info I can find on synthetic rigging.

[andreas.mehlin]

Originally Posted by odonnellryan

Sure on the cost? I've tried to look for some US suppliers and it seems like I'm seeing numbers around $3.5K+ for same length of line that would cost me $1,200 in steel. Over twice as much: hardware would cost me something for the wire but not that much.

Not being negative, there doesn't seem to be very much info I can find on synthetic rigging.

Options aren't that much yet....but with some creativity it gets less...
DM20 is usually 8mm at about 16-20 use/m...thimbles you can fund at about 10-20 usd. To use sta lok...look at about 60-100 use/pcs. 3/8" is about 10usd/m.

[Shoalcove]

Originally Posted by andreas.mehlin

Options aren't that much yet....but with some creativity it gets less...
DM20 is usually 8mm at about 16-20 use/m...thimbles you can fund at about 10-20 usd. To use sta lok...look at about 60-100 use/pcs. 3/8" is about 10usd/m.

What are you using for thimbles? The ones from Colligo are much pricier than that. I was looking at changing an inner forestay but the cost of end fittings seemed high.

[Benz]

Originally Posted by Shoalcove

What are you using for thimbles? The ones from Colligo are much pricier than that. I was looking at changing an inner forestay but the cost of end fittings seemed high.

You can use the stainless steel sailmaker's thimbles from Ronstan if you want a closed sort; otherwise, any heavy-duty teardrop thimble will do. I have used many of both stainless and galvanized on synthetic rigging. If you like the look of them, the round aluminum low-friction-rings are suitable.
That said, the Colligo kit is the classiest-looking if you're doing lanyards.

[Shoalcove]

Originally Posted by Benz

You can use the stainless steel sailmaker's thimbles from Ronstan if you want a closed sort; otherwise, any heavy-duty teardrop thimble will do. I have used many of both stainless and galvanized on synthetic rigging. If you like the look of them, the round aluminum low-friction-rings are suitable.
That said, the Colligo kit is the classiest-looking if you're doing lanyards.

Thanks Ben!
I was concerned if sailmakers thimbles would distort under load. The Colligo thimbles are solid and look stronger. The low friction rings do look good and I’m planning to use them when I make up some running backstays.

[Benz]

Originally Posted by Shoalcove

Thanks Ben!
I was concerned if sailmakers thimbles would distort under load. The Colligo thimbles are solid and look stronger. The low friction rings do look good and I’m planning to use them when I make up some running backstays.

Sailmaker's thimbles take a lot of load to distort, but when they do, it's your first clue....kind of like a fuse. I doubt you'd put enough strain on 3/8" dyneema to distort one, though. Especially if you terminate with a lashing and the load is thus spread. I bent one with a hydraulic puller and a LOT of force. Alu rings take a far higher load to distort--haven't bent one yet, even at 8,000#

[goat]

Has anyone addressed the furler issue with respect to synthetic rigging?

[Shoalcove]

Originally Posted by Benz

Sailmaker's thimbles take a lot of load to distort, but when they do, it's your first clue....kind of like a fuse. I doubt you'd put enough strain on 3/8" dyneema to distort one, though. Especially if you terminate with a lashing and the load is thus spread. I bent one with a hydraulic puller and a LOT of force. Alu rings take a far higher load to distort--haven't bent one yet, even at 8,000#

That’s good to know! I’ll make up a set of running backstays this winter and look at replacing the staysail stay as well. Thanks!

[Benz]

Originally Posted by goat

Has anyone addressed the furler issue with respect to synthetic rigging?

I will address it now: You should never have a furler anyway, so the issue is a false dilemma.

For those who insist on furling, there are code-0 type furlers which don't touch the forestay. They simply ship aft of the synthetic forestay.

[Jim Cate]

I will address it now: You should never have a furler anyway, so the issue is a false dilemma.

Good grief, Ben, give it a rest. This has been an informative thread up till now, please do not sidetrack it with off topic personal opinions.

And, as far as I know, no one is recommending use of furlers on non-wire stays. However, if one used one of the furlers that incorporate a full length plastic bearing tube (or nearly such), perhaps it isn't such an outrageous idea. Dyneema is pretty chafe resistant stuff and it just might work. I'm not volunteering to be the alpha test case, though!

Jim