Synthetic Rigging and Electrons

[Pblais]

I would really be curious to hear if there are any reports of synthetic rigged boats taking direct hits, and what kind of damage to the boat has been observed.

Given the lack of real information about wired rigs and variations of all lightning strikes I think it is fair to say we will not get good information soon given we have so little real science after 40 plus years of wired rigs. That isn't to say it won't ever happen but I wouldn't wait for it.

It is clear to me the structural properties and applications of synthetic rigging are quite well understood while the properties and prediction of lightning behavior is almost nil in every aspect of the marine environment.

[seandepagnier]

It would be interesting to hear any reports of lightning, not just with synthetic rigging. The reason I say this, is lightning (depending on the strike) is sufficiently powerful to vaporize a stainless steel cable. It might be safer to use synthetic shrouds, who knows. (I used to short out power lines as a kid and it would vaporize a 40ft long wire to ground in a split second) Lightning is much more powerful.

Salt water is conductive, fresh water is not (distilled water makes a decent insulator) but my understanding is a tiny amount of salt upsets this. You would likely have salt from spray at least on the lower portions. It is still going to be less conductive than the stainless steel cable though, and as soon as it conducts, it would fry the water off, I doubt it would cause the rigging to fail (this is all just speculation)

Now if you could make the mast also insulated you might have a potential to avoid lightning all together, but this is probably not possible as both aluminium and carbon fiber are conductive. I am afraid to ground my rigging through the ground plate, because lightning might blow a hole in the hull which would be counter productive... any thoughts on this?

[senormechanico]

Originally Posted by estarzinger

The short answer is it probably would melt, if you have a conducting wire either inside or alongside.

If it's just the rope, with no antenna wire, it is less clear but it probably would not melt. The lightening would probably go down the mast. It's possible but unlikely that you could have problems with the splices melting at the mast fittings if there was local arcing/heating

If it was wet, I bet it would melt or explode from steam.

Also, if it had a wire inside for an SSB/HAM antenna, there wouldn't be anywhere enough RF current to produce any significant heating unless you were running a big line amp. 150 watts PEP is no problem.

[estarzinger]

Originally Posted by senormechanico

. . . if it had a wire inside for an SSB/HAM antenna, there wouldn't be anywhere enough RF current to produce any significant heating unless you were running a big line amp. 150 watts PEP is no problem.

We were talking about lightening, not transmit power. The lightening might vaporize the wire and melt the line in the process.

[Wotname]

Originally Posted by Jmolan

.........
However, what about that lightning? Will it heat up the copper wire? Also, I had someone tell me thought side band radios created heat when transmitting. Any one know? Would it be a low heat? ........

Originally Posted by estarzinger

We were talking about lightening, not transmit power. The lightening might vaporize the wire and melt the line in the process.

I think we are talking about both aspects

[estarzinger]

ok, let me rephrase that - I was talking about lightening and not transmit power.

[Jmolan]

There is a couple boats we know of that have run a bare copper wire inside their Dynex Dux backstay. I think one was in the recent ARC crossing, have not heard back, but the initial concern I had about transmitting being a hazard is pretty well confirmed as "no problem"
As crazy as lightening is (I seem to recall a thread here about it) I am set up as such: Aluminum mast with all fittings at the top "pinned" or bolted to the Aluminum Colligomarine.com deadeye pin hole. Every stay is Synthetic Dynex Dux wrapped around the dead eye fitting and Brummel Spliced. The deck is the same fitting using the Dead Eye set up like the old days. 3/16 Dynex lashings that are approx. 1 foot long to a another Colligo aluminum distributer.
Near as I can tell I am insulated both top and bottom by having all my attachment points using Dux.
My mast is stepped on the centerboard trunk, on the sole of the center cockpit. It is only a few feet from the water directly under it in the centerboard trunk. From the Mast base I run a strap to plate located deep in the trunk.
So the lightning strike goes bamm! The mast is like a big unstayed stick that is sitting the the water. At least that is what I "hope" the lightening thinks
I have pics of my rigging in links below. ( I am on the wrong computer to post a pic or two here) The first link you have to wade through another boat before mine.

[estarzinger]

Originally Posted by Jmolan

Brummel Spliced.

If I can detour for just a moment.

I recently got a report from NER that their latest testing had indicated that a tuck and bury splice was stronger than a brummel ("it displayed a higher risk of separation and failure under high tension") . . . . apparently because the brummel had sharter fiber turns than the tuck and bury. Without lock stitching the brummel was less likely to slip at low load but with lock stitching neither slipped.

I am over in France and have been looking carefully at all the high modulus rope work here (and they are the worlds innovators in its use on sail boats) and they don't seem to use the brummel.

Have you done any testing of the Brummel vs tuck and bury? Any specific reason you are using the Brummel?

[Jmolan]

Originally Posted by estarzinger

If I can detour for just a moment.

I recently got a report from NER that their latest testing had indicated that a tuck and bury splice was stronger than a brummel ("it displayed a higher risk of separation and failure under high tension") . . . . apparently because the brummel had shorter fiber turns than the tuck and bury. Without lock stitching the brummel was less likely to slip at low load but with lock stitching neither slipped.

I am over in France and have been looking carefully at all the high modulus rope work here (and they are the worlds innovators in its use on sail boats) and they don't seem to use the brummel.

Have you done any testing of the Brummel vs tuck and bury? Any specific reason you are using the Brummel?

No problem Evan, we can drift all I want, I think I started this thread.....

I would like to see any pics you have of the rigging going on over there. The whole thing is really getting traction now, and there is no doubt more than one way to skin a cat.
Also if you could fwd. me the report you mentioned....I have googled for it, but no luck

Short version: Colliogmarine.com and Briontoss.com worked with 12 strand Dynex Dux on a number of different terminations. They were aware of the tuck and bury at the time.
The problem with tuck and bury (as I understand it) is when the stay is on the lee side. With no load, and a bit of shaking, the potential is for the splice to get loose, and even spit out the fitting. This was a concern on the F-boats with rotating masts. That can be minimized by sewing and lashing the crossovers. I am guessing that might be what you are seeing in France. By having the locking Brummel, there is no chance of slipping out under low/no load. But if your Brummel has too short of a tail, all of the load goes on the lock, you need a longer tail that most realize.
Pull tests with 12 strand Dynex Dux showed that a Brummel needed to have a tail 72 times the diameter of the rope. If you have too short of a tail, all the load comes on the locking crossover, and you have premature failure. (the line broke before the load rating)
With a locking Brummel and 72 times the diameter tail buried (and tapered) the rope broke at 95% of the rated strength.
The lock will contain the fitting, and is the initial place the load comes on. But as it tightens up under load, the tail takes the load. Dynex Dux is so slick, it requires a long tail to muster enough friction.

[Jmolan]

I got this email as a Christamas card from Brion Toss. It went out to anyone on his mailing list. I just checked the site, and he has not posted the tutorial yet. Will keep an eye out for it



Thoughts While Rigging
Brion will present a new series of Fair Leads columns to appear soon on our home page.

The first article in the new series is "Protocols for splicing Dynex Dux".

Sounds a bit rigger nerdy, but this stuff is of great interest to everyone in the sailing world who wants the most high-tech, sexy, light, durable, cost-effective standing rigging yet invented.

And, if you aren't ready to make the leap into an all Dynex rig, feature that you can carry a 200', feather-light, ropey hank of the stuff in your fo'c's'le for spare standing rigging. Handy to have out in the South Pacific or up the Inside Passage. You could loan it to a sailor in need and really be a hero!.....

Don't miss this new series coming soon!

[estarzinger]

Originally Posted by Jmolan

Short version: if your Brummel has too short of a tail, all of the load goes on the lock, you need a longer tail that most realize.

That's terrific. Thanks.

I am on the US Sailing Safety at Sea committee and there is a big discussion about possibly making recommendations or requirements for the terminations on spectra life lines.

I have another related question for you. With a spectra life line, how much chafe would you expect to see at the stanchion exits and do you think some sort of chafe protection should be recommended or required.

My personal experience is that spectra single braid is VERY chafe resistant and I would rather have the bare spectra run thru the stanchion, (assuming any sharp edges have been filed down) and then I could see any chafe that develops. I expect the spectra lines will break at the terminations. But there are others who think chafe will be a big problem and that will be the failure point and chafe protection should be required.

[Jmolan]

Originally Posted by estarzinger

That's terrific. Thanks.

I am on the US Sailing Safety at Sea committee and there is a big discussion about possibly making recommendations or requirements for the terminations on spectra life lines.

I have another related question for you. With a spectra life line, how much chafe would you expect to see at the stanchion exits and do you think some sort of chafe protection should be recommended or required.

My personal experience is that spectra single braid is VERY chafe resistant and I would rather have the bare spectra run thru the stanchion, (assuming any sharp edges have been filed down) and then I could see any chafe that develops. I expect the spectra lines will break at the terminations. But there are others who think chafe will be a big problem and that will be the failure point and chafe protection should be required.

I get this question a lot. You are right, it is extremely chafe resistant. The use SK-75 Dyneema to make butchers gloves. It is really hard to cut. I have run my life lines through the same way and see no 0 nada problems.
There is a shift in perception that is slowly taking place here. I suspect the reluctant one are used to rope. We all are! Well this looks like rope, acts like rope, but it is not rope, not how we know it.
It as best said by a piece Briion Toss wrote a few years back. The whole piece is here:

Brion Toss Yacht Riggers Fairleads Newsletter

To make matters even worse, this newly-reappraised tool exists side-by-side with other rope, of half the strength or less, radically more elasticity, and radically lower price. It's as though, 50 years ago, we were suddenly confronted with an entirely new kind of horse, that looked just like a normal horse, but could run twice as fast. And then, even more recently, we found a horse that could run four times as fast as the original one, but couldn't turn left. All 3 of these horses might look more or less the same, and the latter 2 would appear identical to the casual observer. No problem unless you were sitting on the wrong horse when you needed to turn left...

A related challenge is the matter of scantlings; rope of a certain size simply looks right for a job, based on experience and/or the practices of those whose opinions we respect. In the absence of detailed testing for every application, a considered, carefully-developed visual sense of what is appropriate is a good basis for materials selection. The problem is that a considered, carefully-developed visual sense of what is appropriate takes time to develop, takes the kind of experience, familiarity, and long-term use that rapid development of materials, constructions, and applications tends to preclude. So we are in the process of recalibrating our judgement, and that takes time and effort. A useful saying here is, "Good judgement is based on experience, which is based on bad judgement."

Short version Evan. No chafe protection needed, the best chafe protection you can use is SK-75 Dyneema, that is the skins they sell you to protect this stuff. People ask me about my shrouds and chafe. I tell them anything that rubs against this shroud is going to loose. Anything like sheets, or sails, or a dingy.....

[Jmolan]

I got An email from John Fanta at Colligomarine.com about this.



When we (Colligo) size line for standing rigging or otherwise we do it based on stretch and creep requirements this results in line being 2-5 times stronger than the steel wire it usually replaces. This large strength factor of safety presents a large window for visual failure mode keys to present itself and action can be taken. As long as the line is rigged correctly with no sharp edges you will see any chafe concerns far before the line is damaged enough to present a strength concern for even worst case impact loading conditions. Compare to vinyl covered steel lines which oftentimes offer no visual cues to catastrohophic failures

[estarzinger]

Originally Posted by Jmolan

size line for standing rigging or otherwise we do it based on stretch and creep requirements this results in line being 2-5 times stronger than the steel wire . . . . Compare to vinyl covered steel lines which oftentimes offer no visual cues to catastrohophic failures

What size line did you use for your lifelines? The spec wire is 3/16" and the way the ISAF regulations are currently written would set the dyneema at the same size, which does not give anywhere near the sort of safety margin vs wire you are talking about.

The chafe comparison would be to bare wire. Coated lifelines have been baned by the offshore regulations for years.

[Jmolan]

Good question. I run into this a lot. You are comparing regular Dyneema to wire. It should be about 2x. If you use Dynex Dux (same stuff, only heated and stretched) it should be 3 or 4x. Let's run some numbers.

I am looking for 3/16's life line wire and so far all I can find in coated. I will continue to look for bare 7x7 SS wire for a strength number.

West Marine: 7 x 7 Vinyl-Covered Lifeline Product Display

3/16 7x7 wire (coated) has a breaking strength of 3,700 lbs.

http://www.hampidjan.is/media/pdf/Dy...april_2006.pdf

5mm SK-75 Dynex (Dyneema) has a breaking # 3.5 tons or 7,000 lbs. 2x wire

6mm SK-75 Dynex (Dyneema) has a breaking # 4.2 tons or 8,400 lbs.

That is comparing wire to regular Dyneema. If you look at Dynex Dux

Things are very different. Looking at the chart below:

Dynex Dux | Colligo Synthetic Systems | Colligo Marine

5mm Dynex Dux comes in at #10,472 lbs. breaking strength. You can pick

up a couple pickup trucks with a 5mm or 3/16's rope.....

Short version: 3/16's wire at 3,700 lbs. Vs. 5mm Dynex Dux at 10,400Lbs.

Another quick example. A boat rigged with 1/4" 1x19 will have 6,900 lbs.

of breaking strength when it is new.

Colligo would likely use 9mm Dynex Dux to replace it. 27,500 lbs.

breaking strength. #27,500 Vs. #6,900 And take off a whole bunch of

weight up high. I know I took off at least 40lbs. on my little rig.

lbs. from on high.