Synthetic Searunner

[Jmolan]

This is from another site, Gashmore if you are here, great job on the test bench set up and all you effort. My test bench is right out in the bay rocking back and forth....soaking up the sun.....:-)


http://www.boatdesign.net/forums/sai...lts-24970.html

Gashmore
Junior Member







Join Date: Feb 2008
Rep: 32 Posts: 16
Location: Macon, GA


Dynex Dux pull test- preliminary results
Finally got everything together to start testing the Dynex Dux as standing rigging. It has been a learning experience. I was set up for testing metals and concrete and while the principle is the same the instruments required for testing rope is considerably different. The first thing I realized is you can't glue a strain gauge to a rope. :-) Second steel is a homogeneous material so measurements can be taken on a very short section and applied to the whole. Braided rope must be measured over a long distance to eliminate the effect of local variations.

I followed the Cordage Institute's specification CI1500-2 as closely as possible but tried to include some additions related specifically to standing rigging. It took some time to assemble the equipment needed to produce reasonably reliable results without spending a ton of money.

John at Colligo Marine provided a sample of new 9mm Dynex Dux terminated with Brummel splices around deadeyes. At my request the sample was left in “as spliced" condition without pulling out any splice set. Pin to pin finished length at a reference tension of 10lb was 82.125”. Gauge length on the undisturbed section was 24”.

My normal test rig can only handle 24” so I welded up a framework of 2” heavy wall steel tube 12’ high and mounted the 4"x8” hydraulic cylinder from my tube bender in the base. The pump was geared down to get a piston rate of 1” per minute.

Gross pin to pin measurements were done with a digital readout borrowed from my milling machine interfaced to my laptop. The undisturbed section was measured with a 1" range LVDT position sensor (Macro Sensor GHSD 750) with a resolution of .000026". Tension was measured with a 10,000lb Dillon dynamometer and secondarily was recorded to the laptop through a pressure transducer (Hydac HDA3774) on the hydraulic cylinder calibrated to the dynamometer. Sensor output voltages were fed through a National Instruments A/D interface to the laptop and monitored with two digital multimeters.

The pin to pin data was used for the first pull to get an idea of the splicing set. Pulled to 6,000 lb (25% of MBL) the initial overall elongation was 6.65" including .125" in the undisturbed section. Relaxed to 1,000lb and left for 30 minutes .62" was recovered pin to pin. (I am sure this will vary with the diameter of the line and skill of the splicer.) On subsequent pulls it was used to estimate the elongation of the test unit as a whole. In the undisturbed section all but .010” of the .125” was recovered when the tension was reduced to the reference 10lb tension indicating very little construction stretch.

After the first pull the rope was cycled 50 times to 20% of MBL then twenty pulls were done with dry rope at 68F. The average elongation of the undisturbed section was .00076 in/in/1000lb. This number varied from a maximum of .00079 to a minimum of .00075 trending lower as the testing progressed. This was somewhat better than what I had estimated (.00084 in/in/1000lb.) by interpolating from the Strong test on 13mm. This is probably because the orientation of the fiber is slightly closer to the load direction as the line gets thinner. Estimating from the new chart on the Colligo web site I see we are pretty close to what Hampdijan is saying. (1.7" over 600" at 4,000lb works out to .00071 in/in/1000lb)

To get an idea if exposure to rain typical of standing rigging has any effect I am going to soak the line in fresh water for 24 hours and repeat the test next weekend and will report back.

From these preliminary results 9mm Dynex Dux exceeds the specification of 5/16 1x19 but creep is going to be the controlling factor. Still working on a control to maintain a stable hydraulic pressure over several months for the creep test but should have that solved in the next week or so.

To be continued...

Glenn Ashmore

[Roy M]

This test confirmation of claims made by Colligo, noting equipment, temperature and other variables, is what the scientific method is all about. Verifiable claims and additional testing for new variables helps us to explore new materials and techniques previously unproven, and will lead to further improvements affecting those who choose to utilize the results. Thanks, Gashmore, for your efforts and diligence! Thanks Jack, for introducing the concepts to us and for doing the actual field testing which led to the confirmations of lab claims. You guys did good work and should receive some attaboys for your efforts and abilities to communicate effectively.

[Maren]

[QUOTE=Jmolan;241516]This is from another site, Gashmore if you are here, great job on the test bench set up and all you effort. My test bench is right out in the bay rocking back and forth....soaking up the sun.....:-)

I like to think of it as getting an early start on long term 'real word' testing for UV and strain.

[Jmolan]

Had some fun and today figured out a few new "synthetic solutions"....

This first shot is a block that is used for my staysail. As you can see it is flopped on deck. It does not stand up anymore, and makes a lot of racket when the air is light or when you tack. I removed the spring and shackle. the I took some Dynex SK-60 twine and seized it up. By looping vertical first then frapping it horizontally, it make the block stand right up Now she runs quieter and cheaper.....
On the other side, I wanted to try one of the new "Soft Shackles". You can see the layout. It is made by John from Colligo out of 5mm material from Marlow. They are heating and stretching dynex now also it looks like. The set up should work fine in this application, but I still have that darn banging around to deal with

[Jmolan]

This first shot is a bunch of stuff. It is a really small halyard line. Like 1/8" Dynex that I used for over a year. All I did was tie a bowline then took the loop and cow hitched to a big main sail shackle. Not too cool I know. I was just trying Dux back then and I was trying to see what I could get away with. I learned fast that it was strong enough, but I could not grab that small of line! Any how you can see what looks like melted line in there after I took the know apart. I examined it pretty close and by massaging that spot, the line came back to life and showed no signs of melting. So I guess it was mostly just compression.
I removed the big heavy (dangerous) Mainsail shackle and threw in a soft shackle. It worked just fine on todays test sail. I will probably remove it and just splice the end of the halyard with a similar splice and just have that in the future.
You can see I swapped out one headsail shackle, and hooked up a soft shackle there. It all went great! Still plenty of refinement, but this is just getting started really.
The last shot is for is a "special" for Roy. I had Tony Morrelli along for a sail today and he was wanting to see more headsail tension. So....two soft shackles and a handbilly later we got tension

[Roy M]

You da man!

[Jmolan]

Couple more synthetic solutions dreamed up todays sail....:-)

You can see I eliminated the shackle and the snap shackle on the headsail and added a double loop of SK-60 with a little length because the drifter needed to be a bit higher anyhow. So now I just attach the sail by putting the soft shackle through the loop of twine. Hook it up to the halyard with the soft shackle......Got a shot of the shackles then another without.
I am already thinking about getting rid of my SS plates and putting a loop at deck level and have the legs go down through the deck with stopper knots and washers then epoxy the whole thing in. Would make for a great way to attach stuff and get rid of corrosion and weight. That came to me when I re-configured my bridals on the bow.
You can see what I used to use to run my bridal lines through. Heavy and expensive. Also you can see my attempt to keep it from digging into the deck and edge of the bow. In the past I enjoyed some deep scars there, and I did not want to repeat that.
This is almost too easy. The Dux is so slick that I am confident I will not see and chaff here. And if I do? So what? I can make another one in 5 minutes......Just now I do not like the heavy SS plates out there so I am thinking soft eyes buried in the bow too.....I would probably put hose over it to really make a longer life thing, similatr to the last shot which is the new anchor point for the bow nets........ya gotta love it

[Stillraining]

I'm really curious to see how the bridal soft shackles hold up ...that seems like a bad chafe potential going through just a drilled hole in plate.

[Jmolan]

Originally Posted by Stillraining

I'm really curious to see how the bridal soft shackles hold up ...that seems like a bad chafe potential going through just a drilled hole in plate.

You are right, and the angle the rope will be pulled at is no bueno against that SS hole. I will have to come up with a new solution at some point. Soften the hole edges, or enlarge it and put a hose through there? The way it is I would not want to ride out a blow

Many of the things I am doing is to push this stuff to see what chaffs, breaks, dies or fly's. 3/16" halyards, soft shackles on everything, bronze hanks on synthetic headstay, it has been a lot of fun to try this stuff.

We hauled out yesterday. I have to fly to AK to fish the Bearing Sea for 6 weeks or so.

[Jmolan]

From another site........

Dear Gashmore, Jack and Brian,

It is gratifying to see the cause of Dynex Dux being taken up so enthusiastically in the Northern Hemisphere.

Down here at the bottom of the world, we have been aware for more than three years that this stuff behaves like wire, albeit with a slightly more elastic take-up period.
We have rigged more than 20 vessels ( Keelboats and dinghys, as well as multihulls) using this material and have nothing but respect for the way it deals with load cycling, chafe and U/V attack.

Of particular satisfaction is the way that this material responds to competent rigging skills.
The better job you make of the terminations, including the choice of tensioner ( Colligo, Pre Court, Custom Stainless, Lashing, lanyard or Turnbuckle) The better and more suited to the particular application the set of rigging will be.

One should not assume that Dynex Dux is a "one size fits all" super-material but rather treat it as a quantifiable, proven and documented extra resource that responds well to clear thinking and skilled manipulation.

All the numbers quoted in this and other threads are (surprise, surprise!) in pretty close agreement with the manufacturers figures that have been available for some time on the web, ( Strong Rope and Hampidgan to name the two foremost sites.)

Perhaps now the use of this stuff as direct replacement for 1X19 wire on mainstream criuising and racing yachts will be accepted. We have, as I say been specifying it for three years now.

The crucible that is the Bering Sea fishery has proved the toughness and durability of the gear, now the fashionable world of the "Universal French Plastic Yacht", among others, surely needs to embrace the technology.

While we are on the subject, and to address the spectre of twitchy new owners being suspicious of the material, I seem to remember Brion Toss writing a beautiful piece on how, in the old days, Hemp and Flax fibre rigging (to name but a few of the various natural fibres that were in common use for both standing and running rigging) was the norm and everybody was suspicious of this new fangled metal rigging!

"The more things change, the more thay stay the same" I can not remember who said that first, but it seems apt!

Regards,
Joe Henderson.

[Jmolan]

Got a few shots of the new soft hanks for you all. The stuff is so slick, the sail falls down without touching it....like whooosh!
You can also see the soft shackle I put into the end of the halyard. Soon I will be free of heavy metals....

It has been great fun the last few weeks. The boat is on it's own trailer and all snugged down.
I am flying out today to Seattle then onto Dutch Harbor and fishing in the Bearing Sea for 6 weeks or so. I will check in from time to time as e have INTERNET at the dock now.

[gramos]

its great to see a "pioneer " at work, well done ! i really like the look of this dynex , and am now thinking about converting all my rigging . my only question is how do you tension this rigging once the bottle screws are binned ?? thanks for some great posts and photos , its very encouraging .

[Roy M]

gramos, You can tension them the same way the old salts did with traditonal deadeyes, you use a block and tackle, or your sheet winch or handy billy to suck the block down, take up the slack in the deadeyes, temporarily strop the running part of the tensioning line to the standing part on the deadeye, perform the same on all the other shrouds and stays, then go back and take up some more (if it needs it), until everything seems secure. Then go sail the hell out of it on a windy afternoon and do the same over again, all round to take up any slack that built up. Then do it again awhile later to make it secure. Then you can secure the running part semi-permanently in place, until you notice excessive slack. It's more time consuming than a turnbuckle to set up, but equally useful and considerably lighter. And it leaves you hankering to set up ratlines, buy an eye patch and cutlass, and learn to swagger.

[Jmolan]

Originally Posted by gramos

its great to see a "pioneer " at work, well done ! i really like the look of this dynex , and am now thinking about converting all my rigging . my only question is how do you tension this rigging once the bottle screws are binned ?? thanks for some great posts and photos , its very encouraging .

Gramos, thanks a lot. I got rid of all my bottle screws and use the dead eyes that I got from Colligo. But you do not need an eye patch and cutlass to operate them....

Home

However with the eyes you do not have to use it as a dead eye. There is a hole that is sized for a bottle screw. If you find you get binned on the screws, you can always un-lay the splice and cut back some and re-splice it. I did this recently with 2 year old Dux and it acted just like new rope. No difference that I could see. I did a photo thread of just that at:

http://www.cruisersforum.com/forums/...g-18184-3.html


There are some shots of how I take up on the dead eyes when I am alone. I attach the one end to a halyard and take up tension. Using Dynex is so slick all the pieces slide in the fitting. Then just pinch off the last part with a pair of vice gripes and tie it off. The way I tie it it takes up slack and will put more tension on the standing part, and be secure without tying anymore. And it always come lose with out any fuss.
Either way you go you will be impressed with the difference. Where are you located? I got to run and catch the next plane

[Jmolan]

Made an updated photo page. Hope you enjoy! I am currently sitting in a frozen harbor on the fish boat in Alaska,Aletian Islands metropolis of Sand Pt. Ice surrounds the boat....:-(

jmolan/Alaska stuff/Synthetic Searunner - Photobucket - Video and Image Hosting