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Old 28-09-2008, 19:11   #16
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Originally Posted by cal40john View Post
It doesn't have to be malicious intent to cause damage. What about accidents with any sort of sharp object, or just plain chafe? I have no problems with the strength of the synthetics, I worry about having to replace it much more often than steel due to nicks, cuts, and abrasion that wouldn't have had any effect on steel.

John
John, my experience with synthetics span 7 years now in Ak. Fishing aboard 125' offshore trawler. We had to be convinced it would would last signifigantly longer that wire as it cost so much more, we use a lot of wire trawling.
We found two to three time's the life of wires. It ranges from crane rope to haulback ropes. All that being said we have had to replace some ropes that got hit by some bad chaffe or pinched in a drum or block and shreaded. It is of course our job to keep an eye out for this and prevent as much as we can. It happens much less now than earlier in the period as we were were learning to use the ropes. We had a number of things that needed to be "manicured"...edges, sheaves rounded etc.
I would suggest anyone wanting to get familiar start with a small project. I did my running backs first. Life lines are another good spot to familiarize yourself.
I recently talked with a boat designer who told me he would not be supprised if he stops designing with wire within the next 10 years.
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Old 09-10-2008, 22:34   #17
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We have been using Dyneema for lifelines for 6 months now. First class look and feel with all the strength of SS. Can replace any line in less than an hour myself, anywhere, anytime, by keeping longest length on board.
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Old 16-10-2008, 05:37   #18
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We have 11 mm Dynex Dux upper and lower shrouds (from Mike Strong) on a Schionning rotating carbon mast on our new build 56ft Schionning Wilderness cat with Dynex lashings and Precourt deadeyes and thimbles. Forestay is 12 mm SS Dyform due to foils - only sailed a few times due to engine electronic control cable connection "challenges" and work getting in the way but, so far so good.
This stuff is incredibly light - and easy to install once the eye splices are professionally done and the shrouds pre-stretched. Lashings are easily adjusted.
We have had some intial stretch of the Dynex lashings and settling of the rotation ball and Ertalon cup resulting in some slack in the shrouds but hopefully this is about out of the way - will let you know how we go as we get more time on the water.
Cheers

Paul
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Old 16-10-2008, 08:32   #19
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Does Dyneema have any issues with UV ?
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Old 16-10-2008, 09:01   #20
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Raw Dyneema or Dynex does but this stuff is over-braided with a UV resistant cover. Frankly I am more concerned with effect the toxic atmosphere here in Hong Kong, compliments of the Pearl River delta facories in southern China might have on the synthetics. Only answer might be to get outa here ASAP !!
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Old 23-10-2008, 08:18   #21
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Mike Strong stuff

There is good discussions at Brion Toss forum "spar talk" on synthetics. Aklso Brian Duff is using it on the east coast.



Here is a good link to see the Brummel splice that we use on the Dux for rigging. (notice the expensive fid he uses...hahahah, and the blue masking tape....oh man...this stuff breaks a lot of the old school rules that it has to be expensive and hard to do and require special tools.....stuff...I love it)
Multi Marine :: The Art and Science of Sailing


I recently recieved an email on a 1 year old rig from Aust. I know they rigging new F-boats in Vietnam and a couple 50' cats in the same factory. I will update here as I learn Also I will post a couple shots of the rig pertaining the email here. Good going!....:-)

Hello John,

after a years sailing i have closely inspected my rig on the 42 ft sloop Landfall. In the year i have tightened the lowers once after restepping the mast and then re tightened by a full turn all shrouds and lowers a month ago, backstay is untouched.

On my yacht the shrouds run over the spreader tips, this area was unchanged from when i used wire, i only filed out the spreader grooves to ensure they were smooth



Rig inspection i had already carried out myself, but i then had the same done by a licensed rigger, but one who had no connection with the re rig, i particularly asked to check spreader ends/ dynex and terminations into the mast. We took all leathers off the spreaders.

There was no sign of chafe at any point, there is no sign of wear anywhere. I have over 2/3 adjust still left on all my turnbuckles and the rig is tight. My turnbuckles are standard marine Navtec open body.

We use calibarated dux for all shrouds, lowers, backstay, main halyard, topping lift, and in anti twist luffs on staysails and gennaker. Dynex is used in our steering cable set up.

The only wire left on the boat is the forestay under the furler simply because i cannot fit a thimble inside the furler drum, otherwise that would go as well



Please feel free to use this if you want, hope all is well, i wish this damn economic uncertainty was over

regards

mike
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Old 03-12-2008, 21:11   #22
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Testing

Gashmore have you got any new updates? I see this posted on Brion Toss website. It looks to be a month or so ago......I start splicing the rest of my rig this week and next. I can post some photos if you like. Or check the thread Mutihulls Searunners I post there often.


Dynex Dux redux
I have finally started some quantitative testing on a sample of 9mm Dynex Dux that John at Colligo sent me. I have not completed the creep test but the dynamic stretch figures are in. I am getting a page together on my web site with all the gory details but I thought I would report the preliminary results here.

The purpose of my examination is to get some numbers to compare to 1x19 wire. I tried to follow the Cordage Institute's procedures but as the sample had only 28" clear of undisturbed rope I used an electronic positioning sensor called an LVDT capable of detecting .00005" movement. By adjusting for the specific weight of the rope I had estimated from Strong Ropes figure of .00055 in/in/1000lb for 11mm that 9mm should have an elongation of .00084, about equivalent to 5/16" 1x19. The tested figure (average of 20 pulls after 50 cycles to 20% of MBL was slightly better at .00078 in/in/10000lb. I have to attribute this to the possibility that the fiber is slightly more in line with the load in the smaller diameters.

One major difference I found was the hysteresis or rate of recovery after the load is removed. 1x19 will recover 90% or more of the elongation immediately and the rest over just a few seconds. Relaxed from 5,000lb to 2,000lb Dux only recovers about 60% immediately and another 30% over the next half hour to 45 minutes. It took almost 12 hours to recover all the elongation. What I think this means is that you shouldn't try to tune a rig immediately after it has been loaded heavily. If you dial in the tension before the shroud has fully recovered it will be to tight a few hours later. Also I think it is possible that the leeward shrouds might seem slightly slack immediately after a tack. I will have to examine this more closely.

The other interesting fact is the almost complete lack of torsional deformation. 1x19 will try to rotate as the lay straightens but braid remains in line. I don't think I would do away with cotter pins in the turn buckle though. :-)

Creep test begins next week and will take a couple of months.
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Old 04-12-2008, 05:45   #23
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The only other complete test so far is the wet pull. I soaked the sample in water for 24 hours and repeated the first test. Statistically identical to the dry pull. Maybe .00002" difference. Within the margin of error of my equipment.

The creep test has only been running for 10 days. 2,500 lbF at 82F and so far nothing has happened. The creep rate is so low that I expect it will be February before have anything to report.
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Old 04-12-2008, 05:51   #24
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Gashmore

The earlier post talked about the problem of the longer time needed for the elongation recovery. Have you considered a test that investigates this aspect. Ie. replicates the tacking cycle in confined waters.

and also what happens to the rope if it is tensioned before it has finished its elongation recovery, whether this does add additional stress to the rigging, and effect on subsequent cycles.
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Old 04-12-2008, 05:56   #25
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Raw Dyneema or Dynex does but this stuff is over-braided with a UV resistant cover.....
I think this is the $64.00 question. How long will the U/V coatings last? We know that this miracle line absolutely requires the U/V coating to retain it's incredible strength.

I love the idea of replacing 1x19 wire, However, call me conservative, but I will wait until there's more info available as in my part of the world U/V is a prime consideration.
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Old 04-12-2008, 07:13   #26
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I should explain a little about hysteresis. It does not effect the ultimate stretch length. For example take a 9mm shroud 50' long will stretch at a rate of about .47" per 1,000 lb of load. Tuned to 2,000 lb (8% MBL) at rest it will stretch 1.4" when loaded to 5,000 lb (20% MBL). On the next tack the new windward shroud will stretch 1.4" and the distance between the hounds and chain plate on the new leeward shroud will decrease that same amount but the shroud will only retract about 1" and the load on the lee shroud will drop to about 1,000 lb. On the next tack the load increases and the shroud will stretch again but because it is already stretched more than it normally would be the rate will be lower and the ultimate stretch will return to the original 1.4".

I don't think hysteresis will present a problem because the controlling factor in sizing a shroud will be controlling creep. That means keeping the at rest load below 8-10% of MBL. To do that you have to size the rope larger than the elongation modulus and maximum safe load alone would indicate. That will result in a rig that is stiffer than it would be with wire.

As to UV degradation I don't have a UVB source strong enough for a rapid aging test and a professional service would be incredibly expensive. However I think the Dux will do much better than other Dyneema based line. Dissecting the yarns it looks like Dux is coated with UV inhibitor in the fiber before it is yarned and braided. Amsteel Blue appears to have been coated after braiding as the interior yarns are still raw.

I am hoping that John will send me a sample of some line he had on his boat in Mexico for the last 18 months so I can check the fiber for damage under a microscope. Also the textile school at my alma mata has equipment to test individual fibers. Lord knows I pay them enough every year just for the privilege of buying football tickets they should be willing to help. :-)
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Old 04-12-2008, 07:34   #27
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Good stuff

Gashmore, I am rigging this week and next. Seems like all this stuff takes longer than I had thought. I will be using 9mm headstay and backstay, and 7mm upper and lower shrouds, and 7mm baby (fwd.) stay and lower backstays. The Searunner Trimaran is a cutter rig with 3 headstays (jibstay, staysail stay, and baby stay fwd.) double spreaders, uppershrouds, lower shrouds and lower aft stays. As well as a single backstay and running backstays...whew!
I have my 7mm runnning backstays that have been in the Sunny San Carlos sunshine for 18 months now. I do not see any fuzzing or anything other than dirtier from being in a dusty shipyard for almost a year. They have not been under a load in almost a year.
I have seen Dux fail. In Alaska the smallest we use is 5/8" on our 12 ton deck crane. This is used in many terrible aplications over the life of he rope. By that I mean the crew will lash up lift or go around corners that are really not very cool as far as chaffe goes. The lower part of the line will get fuzzy and the guys just cut it back and resplice it, or end for end it. If they fail to do this it can break right at the end of the splice. Where the tail end the tuck. Although most the time the crew uses a tuck splice, not unlike other 12 strand ropes. This is the raw stuff, not coverd. We can order covered stuff from Iceland and it is hard as a rock and NEVER chaffes. But that is for the big stuff like the 1 1/4" line used on a 50 ton lifting winch for big bags of fish.....:-)
I guess I will be conducting my own experiment here on UV. I can see providing you with some test line in a year or so. Thanks so much for your testing, this is way cool....:-)
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Old 04-12-2008, 09:50   #28
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Jack and Gashmore,


All very interesting and informative.

Jack, I was wondering about your choices on line size for your cutter. The original rig design plans from Brown/Marples indicate 1/4" primary wires for backstays, and shrouds. The backstay bridle is, the sub forestay and the intermediate shrouds are all 7/32". I am just curious why not to use 9 mm throughout where the 1/4" and 7/32" is called for in the plans?

Thanks for the detailed report on your new rigging plan and to you Gashmore for all the analyses. Hopefully in a year or so when Jack sends you a sample of long-term UV exposure, you can give us a good report there as well.

Rann
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Old 04-12-2008, 11:53   #29
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Comparisons

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Jack and Gashmore,


All very interesting and informative.

Jack, I was wondering about your choices on line size for your cutter. The original rig design plans from Brown/Marples indicate 1/4" primary wires for backstays, and shrouds. The backstay bridle is, the sub forestay and the intermediate shrouds are all 7/32". I am just curious why not to use 9 mm throughout where the 1/4" and 7/32" is called for in the plans?

Thanks for the detailed report on your new rigging plan and to you Gashmore for all the analyses. Hopefully in a year or so when Jack sends you a sample of long-term UV exposure, you can give us a good report there as well.

Rann
Rann, my choice is a matter of strength is all. As I recall 7mm Dux is rated at 15,500 lbs. breaking strength. You can look up the best dyform stainless wire at 1/4" is like 9k strength. Actually look at this page down at the bottom John does a compairison of wire and ropes.

Dynex Dux | Colligo Synthetic Systems | Colligo Marine

The 9mm I am using is 26,500 lbs. breaking strength!....How much does the boat weigh? 7K?

Anyhow, I have a feeling we are over engineering it as it is...:-)
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Old 04-12-2008, 15:05   #30
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Anyhow, I have a feeling we are over engineering it as it is...:-)
I think you are close to the money. As I said, choose synthetics for creep rather than load or elongation. If you size to keep the static load under 8% to eliminate creep the worst case dynamic load will be well covered.
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