Re rig in Dyneema

[Oceanride007]

Uncivil nicely observed, the closest in the image is the intermediates its slighly less dia than than the cap shrouds, 9 against 11mm, as I understand it the 9mm is skinny enough and achieves extra strength by the double turn, with the 11mm its needs a bit of braid to give the strength over the tight turn of the 10mm hardware.
I don't know lots but I suspect this plain dyneema can take a tight turn but not too tight. This rigger has 25 years of experience with dyneema without a failure. And has extremely good reputation, here and OS. The problem is what he knows is not downloadable. Still he involved me in the process, if you have any questions I can pass them on.

[UNCIVILIZED]

One of the members here, Evans Starzinger, has done, & continues to do a lot of testing on Dyneema & it's use in replacing wire. Which, he's made contributions to countless threads on the subject here on CF. Particularly discussing strength losses in Dyneema where it has to conform to small radii. Many of these discussions are easy enough to find, both on CF, & online.

There's some discussion on most of the above issues in this PDF https://cruisingclub.org/pdfs/sas_lifelines.pdf
Including the confirmation of 5:1 being considered the minimum bend radius for Dyneema. Which even at that ratio, it loses 15%-20% of it's strength. And this is prior to any UV or service generated degradation.

To put it another way, it can't hurt to do some studying online about this.

[BlueBuddha]

Does anyone know what would be the standard weight savings from using Dyneema over SS, say on a 40-45' cat? I have read every page on Colligo Marine and although they discuss the weight savings extensively, there is no clear comparison table.

I read often the idea of 1/5th of the weight of SS, which sounds impressive but then the numbers I get reduced my enthusiasm.

Let's say you have a 45ft Cat using 500ft of 12mm SS. At 0.20lbs per ft, we are talking about 100lbs total for the SS rig. If Dyneema is 1/5 of the weight (i.e., 20lbs) you would be saving 80lbs on a 20T boat. That seems like insignificant weight saving unless you are racing professionally.

So I either made a mistake in my weight savings calculation or my expectations for weight savings were a bit too high.

Any thoughts?

[jfranta]

Hi, 16 mm dux would replace 12 mm 1 x 19 and weighs .026 lbs per foot. So 500 feet of 16 mm dux would weigh 13 lbs, 1/8 that of 12 mm 1 x 19 wire. On average, the entire rig is usually 1/4- 1/5 the weight of the wire rig. but it all depends how you measure and on what you start with, wire, rod, turnbuckles, Navtangs, etc, and what you end up with, cheeky tangs, lashings, turnbuckles etc. Tender boats see a great advantage, not so tender, heavy boats not so much. Keep in mind the change in righting moment on your boat due to the weight being aloft is very significant. Pitching issues become less and overall seaworthiness is better. One 60 ft cat owner said he felt much safer when banging upwind and impact loading the whole rig, splices, vs swage or swageless fittings give a much safer feeling. By far though, a dux rig is much safer as it is full inspectable and your factor of safety goes from 4 or so to 8 or more.

Lots of information on customers boats on our facebook site also.

John Franta, Colligo Marine.

Originally Posted by BlueBuddha

Does anyone know what would be the standard weight savings from using Dyneema over SS, say on a 40-45' cat? I have read every page on Colligo Marine and although they discuss the weight savings extensively, there is no clear comparison table.

I read often the idea of 1/5th of the weight of SS, which sounds impressive but then the numbers I get reduced my enthusiasm.

Let's say you have a 45ft Cat using 500ft of 12mm SS. At 0.20lbs per ft, we are talking about 100lbs total for the SS rig. If Dyneema is 1/5 of the weight (i.e., 20lbs) you would be saving 80lbs on a 20T boat. That seems like insignificant weight saving unless you are racing professionally.

So I either made a mistake in my weight savings calculation or my expectations for weight savings were a bit too high.

Any thoughts?

[jfranta]

I certainly do not want to switch the world to lashings, they are very limited in their ability to get tension. Most of the boats we rig are with turnbuckles, they are very good at what they do. We highly recommend boats over 30 ft use turnbuckles. In fact, I have had some good discussions with yacht designers that want to use lashings, they are dangerous on larger boats.

JOHN FRANTA, Colligo Marine.

Originally Posted by Stumble

I wouldn't worry about 9 year old turnbuckles unless they showed clear evidence of failure. John Frampta at Colligio keeps wanting to switch the world to lashings, and I get the idea. But I don't by it. Dyneema shrouds with turnbuckles are in my eyes the better way to go.

[BlueBuddha]

Originally Posted by jfranta

Hi, 16 mm dux would replace 12 mm 1 x 19 and weighs .026 lbs per foot. So 500 feet of 16 mm dux would weigh 13 lbs, 1/8 that of 12 mm 1 x 19 wire. On average, the entire rig is usually 1/4- 1/5 the weight of the wire rig. but it all depends how you measure and on what you start with, wire, rod, turnbuckles, Navtangs, etc, and what you end up with, cheeky tangs, lashings, turnbuckles etc. Tender boats see a great advantage, not so tender, heavy boats not so much. Keep in mind the change in righting moment on your boat due to the weight being aloft is very significant. Pitching issues become less and overall seaworthiness is better. One 60 ft cat owner said he felt much safer when banging upwind and impact loading the whole rig, splices, vs swage or swageless fittings give a much safer feeling. By far though, a dux rig is much safer as it is full inspectable and your factor of safety goes from 4 or so to 8 or more.

Lots of information on customers boats on our facebook site also.

John Franta, Colligo Marine.

Thanks John. You make a good point, the weight savings aloft have benefits beyond the total net weight savings as it can lower center of gravity and likely produce better sea motion. I see how just looking at the net weight savings numbers only people may miss the related benefits. The added safety is another big plus. Thanks for the info.

[estarzinger]

Originally Posted by UNCIVILIZED

There's some discussion on most of the above issues in this PDF https://cruisingclub.org/pdfs/sas_lifelines.pdf

Just fyi . . . . That paper is out of date and incorrect.

There was a more recent better version released (dated jan 2014 I believe), but it seems to have disappeared since the dyneema lifelines were banned (from monohull racing) by world sailing.

[UNCIVILIZED]

Originally Posted by estarzinger

Just fyi . . . . That paper is out of date and incorrect.

There was a more recent better version released (dated jan 2014 I believe), but it seems to have disappeared since the dyneema lifelines were banned (from monohull racing) by world sailing.

Yep, that part I knew, & perhaps should have mentioned it. I was just looking for a reference which covered some of the pertinent info being discussed.
Might you be kind enough to post a touple of links to references that better cover Dyneema & bend radii.


As to the weight aloft benefit, this may sound like a racing thing, but it truly is universal. And that's that when you have less weight up high, the rig moves less with each wave the boat strikes, or puff which hits the sails. Along with the same reductin in the boat bouncing around. And all of this equates to the wind's flow staying better attached to the sails. Which in lay speak means better performance. Especially upwind. So if you're in a situation where making progress uphill is critical... having put the rig on a "diet" really helps. Plus, the boat's easier motion, is less wearing on the crew.

Also, consider the lengths serious racing boats will go to in order to reduce weight aloft. Stripping the covers off of halyards. Ever more svelte running rigging. Spars with 3 sets of spreaders (or more) so that they can use lighter mast tubes. Heck, the difference in weight between rod rigging & wire is tiny. Especially in comparison to going from wire to dux. Yet serious racing boats purchase it almost without thought, in addition to spending huge amounts of $ for carbon fiber masts, & ever lighter rigging.

[paxfish]

Originally Posted by jfranta

I certainly do not want to switch the world to lashings, they are very limited in their ability to get tension. Most of the boats we rig are with turnbuckles, they are very good at what they do. We highly recommend boats over 30 ft use turnbuckles. In fact, I have had some good discussions with yacht designers that want to use lashings, they are dangerous on larger boats.

JOHN FRANTA, Colligo Marine.

Just curious, John, why are lashings dangerous on larger boats versus smaller?

[Stumble]

Originally Posted by jfranta

I certainly do not want to switch the world to lashings, they are very limited in their ability to get tension. Most of the boats we rig are with turnbuckles, they are very good at what they do. We highly recommend boats over 30 ft use turnbuckles. In fact, I have had some good discussions with yacht designers that want to use lashings, they are dangerous on larger boats.

JOHN FRANTA, Colligo Marine.

Clearly my joke didn't come across very well. I wasn't seriously suggesting you think everyone should use lashings. In fact my Corsair is rigged with your stuff including the turnbuckles.

[roverhi]

You get the tension on lashings by tightening them on the leeward side under sail, flop over and do the other side. Don't see dangerous in that unless you have an inatentative helmsman who tacks or jibes while the lashings are loose. Don't know whether you can get enough tension on the rigging doing the above?? Can you enlighten us a bit more jfranta

[estarzinger]

Originally Posted by UNCIVILIZED

Might you be kind enough to post a touple of links to references that better cover Dyneema & bend radii.

Look up a thread on SA titled something like "bend radius in large diameter Dyneema". In it I post the results of a test series where I had a certified lab break over 150 samples of 12mm heatset Dyneema - testing bend and throat angles.

This is a quite "settled" topic in the industry. The test lab thought I was wasting time and money examining it in such detail (and the results basically confirmed all the prior industry data).

Regarding the Dyneema rigging and weight aloft question - for a cruising context you will find the quantitative "benefit" to be quite small (near un-noticsble in a cruising contest - e.g. way less than a dirty bottom). Such "small" benefits are important in racing, but more a personal "pride" issue in cruising. There are decent ways to get the potential benefits quantitified for any particular boat, or in general - but like my bed radius test, it is a well understood "settled" topic and the answer will be "small".

I could say a lot more/detailed about both topics . . . . . but will not . . . . Because it would likely cause personal attacks.

[UNCIVILIZED]

Originally Posted by roverhi

You get the tension on lashings by tightening them on the leeward side under sail, flop over and do the other side. Don't see dangerous in that unless you have an inatentative helmsman who tacks or jibes while the lashings are loose. Don't know whether you can get enough tension on the rigging doing the above?? Can you enlighten us a bit more jfranta

Keep in mind I haven't tested this. But when using lashings I'd think it would be tougher to tune a rig with precision, particularly a multi-spreader rig. As the relative tensions of the various shrouds will differ, ergo the amount of tightening each will need will vary. And when you tune a rig to compensate for this, you have a reasonably calibrated way of doing so via turnbuckles. Since you can count how many turns you put onto or remove from each turnbuckle. However, I'm thinking that trying to do something similar with lashings could be more difficult, & at a minimum entail a lot more cycles of tack-n-tune, repeat, in order to get things right.

This would especially be the case when trying to tune out multiple S-curves, in various panels of the rig. Which aren't a good thing to have in any rig to begin with, let alone when going to weather in 20kts of breeze (or more), which is when a lot of crucial tuning is done.

And I don't think that I would even care to attempt to tune a discontinuously rigged boat without turnbuckles. It's more than enough work to do so with them.

I know that when tuning rigs on anything with turnbuckles, from dinghies to maxi's, we count the number of turns. And most racing boats from about 30' & under have calibrated turnbuckles, with measuring scales etched right into the hardware itself. Plus which, detailed logs are kept of rig adjustments, & not just how much was added or taken off of shroud X. But what the optimal settings are for environmental conditions Y, & Z.

Which, little, to none of the above could be done with lashings alone. And it also takes longer to adjust lashings than turnbuckles I'd think. A critical factor in competition sailing, where it's common to adjust your standing rigging in between tacks as the breeze & sea state changes. Or in between races, on days where there are several. Doing so for variances in wind of as little as 2kts (sometimes less).

On this, if I'm wrong, I'm curious to hear from folks who've had differing, real world, experiences with it. And no, I'm not bashing lashings. In some applications, & at certain times they surely have a place.