Converting to synthetic standing rigging, what to do about the D2s…

[GILow]

Originally Posted by The Yacht Rigger

Do you mind sharing what it is about the Blue Wave fittings you are uncomfortable about?

Well, for a start the Australian distributor could only offer me fittings for rope up to 10 mm. This suggests that the fittings are not really designed for the sorts of loads in a 44 foot cruising boat.

And, although friendly and helpful, it was clear they really knew nothing of the use of their product in boat rigging. That’s kinda alarming.

Also, the fittings are heavy and VERY expensive. Just crazy expensive.

Then there’s the mild niggle of the tight radius around the little “bone” fitting and how that might diminish the strength of the system.

A pity, because they look nice.

[GILow]

Originally Posted by Benz

Loops are described as used "in vertical," which means stretched out as long as they'll go (the load rating is measured thus)

"In basket," which means folded over, (which is how you'd feed it through the thimble, bringing the two ends of the loops to the turnbuckle pin).

"Boned," (though I prefer 'toggled' as being more historically accurate), in which the basketed loop is closed with a "dogbone" or toggle.

"Choked," in which you make a girth hitch or lark's head with the loop.

I'll attach a picture of a loop in basket: it's the one on the aft side of the mast, holding a low-friction-ring to the eyestrap. The other loop visible is a toggled eye-to-eye. Both are of my own construction.

Thank you, a true case of a picture being worth a thousand words.

[s/v Jedi]

Originally Posted by GILow

Well, for a start the Australian distributor could only offer me fittings for rope up to 10 mm. This suggests that the fittings are not really designed for the sorts of loads in a 44 foot cruising boat.

And, although friendly and helpful, it was clear they really knew nothing of the use of their product in boat rigging. That’s kinda alarming.

Also, the fittings are heavy and VERY expensive. Just crazy expensive.

Then there’s the mild niggle of the tight radius around the little “bone” fitting and how that might diminish the strength of the system.

A pity, because they look nice.

I have looked at these fittings after the YachtRigger brought them to my attention. From what I saw, I have nothing but respect for their engineering and build quality. There is no problem about a tight radius, this has proven itself completely incl. aboard Jedi (different hardware, same radius) and the splice guarantees the strength.

Weight isn’t something I checked but I assumed it to be equal to a mechanical fitting for wire so equal in that regard.

Price and availability in Australia… yes again and again sailors down under find their wallets bleeding over costs, taxes and duties (I’m not allowed to talk about that here on CF though as it’s a censored subject) but that’s no excuse for a distributor to not be up to full inventory and expertise. But even when the distributors I deal with are knowledgeable, and some truly are, then I still don’t rely on anything they tell me: I will research it fully myself, find other buyers and talk to them etc. Often the distributor doesn’t mind at all and even directs me to other buyers for references.

[GILow]

The prices on the Bluewave stuff were hideous in the UK too, so for once it may not be an exclusively Aussie thing. As for the sizes, most of the stuff in the catalogue seems to stop at 10 mm rope with larger sizes by request.

Anyway, I’m happy with the look of the Colligo stuff and you guys on CF have given me what I feel is a good solution for the D2s.

The standing rigging came out a little over budget, but the sails came out a lot under budget so on balance the project has not yet gone off the rails.

Subject of which… toe rails next… another unicorn product here in Oz.

[thinwater]

Originally Posted by GILow

I don’t WANT to use bigger turnbuckles, the problem is the Colligo terminators are all sized for the bigger pins.

I was thinking I’d missed something there but the response from Colligo suggests I hadn’t.

Matt

You should be able to bush to matching pins. No, you do not just use smaller pins.Ask Colligo. With turnbuckles aloft you have a different situation.

[GILow]

Originally Posted by thinwater

You should be able to bush to matching pins. No, you do not just use smaller pins.Ask Colligo. With turnbuckles aloft you have a different situation.

“Ask Colligo”. I did just that. I’ve said so a couple of times now.

If they thought that was a solution they would have proposed it. Instead, as I said earlier, they suggested converting to continuous rigging. If THAT’s their response it’s clear they don’t have a workable solution using their gear. I mean that’s a HUGE change just to address the issue with the D2s.

[Benz]

A closed thimble with Dyneema shroud...
This is DM20 with an Dyneema cover, but DUX will go on it as well.
Thimble cost about $8 USD at US Cargo Control.

[GILow]

Originally Posted by Benz

A closed thimble with Dyneema shroud...
This is DM20 with an Dyneema cover, but DUX will go on it as well.
Thimble cost about $8 USD at US Cargo Control.

Certainly a nicer price than the Colligo terminators.

[Lee Jerry]

Originally Posted by GILow

Have a look at a discontinuous rig diagram for a double spreader rig. You’ll see the D2s are only a few meters long. It’s only the D2 we are worried about here, the other stuff is all sorted with nice big 13 mm and 11 mm rope.

I understand the discontinuous rig breaks the length of the shrouds into shorter segments...

Let me try it this way - the shorter the length, the less creep there will be in the Dyneema version. However, the shorter the length, the more sensitive the tension will be to changes in length. Thus I still don't see how you can decrease from the recommended "equivalent" size of Dyneema for the previous wire size. I don't see how creep is reduced. (But as I said, maybe I'm missing something.)

[s/v Jedi]

Originally Posted by Lee Jerry

I understand the discontinuous rig breaks the length of the shrouds into shorter segments...

Let me try it this way - the shorter the length, the less creep there will be in the Dyneema version. However, the shorter the length, the more sensitive the tension will be to changes in length. Thus I still don't see how you can decrease from the recommended "equivalent" size of Dyneema for the previous wire size. I don't see how creep is reduced. (But as I said, maybe I'm missing something.)

It’s not just the length, his wire rigging uses a smaller diameter wire for these as well, so I don’t understand why not a smaller size for Dyneema.

As for all Dyneema rigging, as long as one has an aluminum mast, thermal expansion of the rigging becomes the inverse of that of the mast, which means frequent tuning with temperature changes and this will hide the creep for the most part.

I think a carbon fiber mast would be so cool but so expensive… people still find them from racers or wrecked boats though

[Lee Jerry]

Originally Posted by s/v Jedi

It’s not just the length, his wire rigging uses a smaller diameter wire for these as well, so I don’t understand why not a smaller size for Dyneema.

I understand that point. I think it comes down to a couple issues: It's only a difference of 1mm in wire size (7 vs 8); the Colligo conversion table (at least the one I saw) doesn't list 7mm wire (only 6.4mm and 8mm); the Dux is only available in discrete sizes of 9mm and 11mm (10mm would probably be the right answer if available). I think that drives 7mm wire to 11mm Dux.

As for all Dyneema rigging, as long as one has an aluminum mast, thermal expansion of the rigging becomes the inverse of that of the mast, which means frequent tuning with temperature changes and this will hide the creep for the most part.

This is generally true but irrelevant, or inconsistent - why not apply that logic to all of the rigging and downsize that as well (i.e. more for strength and less for creep).

[s/v Jedi]

Originally Posted by Lee Jerry

I understand that point. I think it comes down to a couple issues: It's only a difference of 1mm in wire size (7 vs 8); the Colligo conversion table (at least the one I saw) doesn't list 7mm wire (only 6.4mm and 8mm); the Dux is only available in discrete sizes of 9mm and 11mm (10mm would probably be the right answer if available). I think that drives 7mm wire to 11mm Dux.

This is generally true but irrelevant, or inconsistent - why not apply that logic to all of the rigging and downsize that as well (i.e. more for strength and less for creep).

Because they have the perfect size Dynex Dux for that. For these D2’s there isn’t so a compromise must be found and the 9mm Dynex is an option just like the 11mm is. Another option would be to look at other heat set Dyneema products.

[GILow]

Originally Posted by Lee Jerry

…
… However, the shorter the length, the more sensitive the tension will be to changes in length. …

I’m thinking about this. Not saying you are wrong, but I think there’s a subtlety here around elasticity that needs to be considered.

I’ll think about it some more.

[s/v Jedi]

Originally Posted by GILow

I’m thinking about this. Not saying you are wrong, but I think there’s a subtlety here around elasticity that needs to be considered.

I’ll think about it some more.

The thing is that we don’t care so much about tension as we do about length. The reason we pretension shrouds is so that they don’t get much longer when loaded and that the leeward shrouds don’t start flapping around (tension goes down instead).

To tension my shrouds to 20% of breaking strength, I use a 2-meter long measuring stick taped to the shroud at the upper end, mark the shroud at the lower end, then tension until the lower mark is 4mm (IIRC) below the stick. So every 2 meter section is stretched by 4mm.

So when I have a 4 meter length and stretch it 4mm then it only has half the tension of the 2 meter length stretched 4mm. So Lee Jerry is right (he normally is )

[The Yacht Rigger]

Originally Posted by GILow

Well, for a start the Australian distributor could only offer me fittings for rope up to 10 mm. This suggests that the fittings are not really designed for the sorts of loads in a 44 foot cruising boat.

And, although friendly and helpful, it was clear they really knew nothing of the use of their product in boat rigging. That’s kinda alarming.

Also, the fittings are heavy and VERY expensive. Just crazy expensive.

Then there’s the mild niggle of the tight radius around the little “bone” fitting and how that might diminish the strength of the system.

A pity, because they look nice.

Thanks, all good feedback. Yeah we are working on expanding the size range in the US. Already have some rope eyes that will take up to 16mm. Other fittings to follow.