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Rope/knot/splice load testing


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#1301 Brion Toss

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Posted 07 April 2014 - 10:30 PM

This is starting to remind me of an old Tom Robbins riddle: "If one and a half chickens lays one and a half eggs in one and a half days, how long would it take a wooden-legged monkey to kick all the seeds out of a dill pickle?"

But actually, I see now that the load on the eyes would remain approximately the same. That leaves the huge radius prescribed for the standing part, and there the load would in fact be doubled, yes? If that is so, it explains the extra-generous required radius.



#1302 allen

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Posted 07 April 2014 - 11:09 PM

^^ exactly, except I didn't understand the pickles ;-)



#1303 allen

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Posted 07 April 2014 - 11:39 PM

New topic.  First a confession.  I worked all day on this before realizing it might be a little too difficult to untie for use as a halyard shackle replacement.  But is is clearly a good candidate to replace a halyard knot in Amsteel as it should be line strength if you get the length of the bury right so there is a section of double strength outside the headboard.  At least that is my assumption.  I am sure it can be untied, just not sure how easily.   @Estar, care to test the strength?  It is easy to make and can be tied to a ring or shackle to test.

http://L-36.com/soft_toggle.php   I created good instructions for tying the Chinese Button Knot that terminates the halyard.  It can be tied from one end.  

http://L-36.com/chin...button_knot.php

 

 

soft_toggle_soft_toggle_9.jpg

 

 

 

soft_toggle_soft_toggle_13.jpg

 

 

soft_toggle_soft_toggle_17.jpg



#1304 allen

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Posted 07 April 2014 - 11:47 PM

Can you elaborate on the tenex to Amsteel brummel splice.  Are you talking about the one on my web site or do you have something else in mind?  I am always looking for new ideas.

 

I was just going to do this one:

http://www.neropes.c...nd_Brummell.pdf

 

I've done this using 5/32" (might have been 3/16") Amsteel and 3/8" Salsa braid for the main sheet on my dinghy.  Salsa Braid is tight but doable.  Tenex looks like it should be easier, but I haven't tried it yet.

I would be surprised if you can get the 3/8 Tenex inside the 3/16 Amsteel.  Salsa braid and Tenex look the same except for the color so maybe you can.    I had a difficult time getting half the tenex inside my Amsteel but that was probably 5/32.  As a backup, you can bury half the strands of the Tenex and bury a long section of the Amsteel.  Please let us know how it works out.

 

Allen



#1305 skins

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Posted 07 April 2014 - 11:49 PM

You have some pretty hot skins there allen :)

#1306 rule69

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Posted 08 April 2014 - 01:06 AM

I'm probably doing it wrong but it looks to me that the tucked / spliced knot tails could have a failure at less than 1d strength if they aren't snug when they get loaded. That is, if the tail is pulled out a bit before the load comes on the load will be on the standing part which will be weakened by the deformity. Maybe the tucks need lock stitching / brummells?

 

Attached File  button splice err.png   322.32K   1 downloads



#1307 allen

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Posted 08 April 2014 - 01:15 AM

^^ Yes, you need to make sure the bury is all the way in.  Did this picture represent a failure after it was loaded or is it just not tucked correctly?  I will make some notes on the web page. It was a little hard to get the buried section all the way in over its cover.  It didn't want to go in naturally.

 

It should look like this when you are done with the bury and if it doesn't you should pull it out and do it again.

 

soft_toggle_soft_toggle_9.jpg

 

The key is this step.  Make sure the buried line is all the way inside the cover before you cut anything.  Look right at the knot to see.

soft_toggle_soft_toggle_6.jpg

 

Allen



#1308 rule69

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Posted 08 April 2014 - 01:28 AM

^^ It was buried and worked hard by hand but not put on a winch. It looked good but I was able to easily pick the splice out when it was not loaded as shown in the picture. The worry I have is that if even a good the splice of this type gets moved when not loaded it could work lose.

 

When I had it all tucked in and put a small capsizing force on the knot -- rotated about the standing part so the tucked part was in tension -- the tail did move. In practice maybe the knot would pull tighter when the full load came on it rather than breaking at the standing part? Or perhaps I'm not groking how to make the bury stay put when the line isn't tensioned? Isn't this what stitching or a brummell is usually supposed to prevent?



#1309 allen

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Posted 08 April 2014 - 01:33 AM

^^ Yes, it should be stitched.  I added a note on the web page.  If stitched, the knot should tighten symmetrically so perhaps both sections would come out a bit but not one like when you pull on the buried section.  You could use a brummel but I think you would need access to both ends of the halyard.  Either a brummel or stitching should be equally good. 

 

UPDATE:  I took my sample to the test bench.  I can put around 1000 pounds on it.  All was good news.  It was easy to untie by just pressing the loop away from the button.  Nothing odd happened with the bury coming out.  I did not test it anywhere near failure however as this was 1/4 inch Amsteel.  But I was pleased how easy it was to untie the knot.

 

Allen



#1310 rule69

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Posted 08 April 2014 - 01:52 AM

^^^ Thanks!

 

Your button instructions are very good too.

 

The button with tucked tail looks classy in amsteel. I might use it at the mast head for my 2:1 main halyard when it gets changed out. I'm not sure I can train the owner of my PHRF ride to do the halyard tie. For that I still suspect I'll use a shackle (likely soft but maybe the unimproved type) in an eye splice.



#1311 allen

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Posted 08 April 2014 - 01:57 AM

I'm not sure I can train the owner of my PHRF ride to do the halyard tie. For that I still suspect I'll use a shackle (likely soft but maybe the unimproved type) in an eye splice.

Same thing I did.  I want my crew to be able to figure out how to work it.



#1312 Alex W

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Posted 08 April 2014 - 04:07 AM

I would be surprised if you can get the 3/8 Tenex inside the 3/16 Amsteel.  Salsa braid and Tenex look the same except for the color so maybe you can.    I had a difficult time getting half the tenex inside my Amsteel but that was probably 5/32.  As a backup, you can bury half the strands of the Tenex and bury a long section of the Amsteel.  Please let us know how it works out.

 

I played with it at home today using new line.  I don't have Tenex, but I have some NERopes Regatta Braid which I think may be similar?  It is a single braid 12-strand dacron rope that is a bit bulkier than Salsa Braid.

 

1/4" dyneema with 3/8" regatta braid:

13708532545_5f90d7802d_z.jpg

 

That was pretty easy, I think it might be easier than putting an eye splice into the Regatta Braid.  Buries are a little short since I just did this as a test and don't intend to use it.

 

I tried 3/8" Regatta Braid to 3/16" dyneema, but couldn't get the bury to work.  5/16" to 3/16" probably would.

 

I was curious to see how far I could taper this down in another step.  1/4" dyneema to 3/16" dyneema was easy, 1/4" to 1/8" didn't work (I couldn't fit the 1/4" into the 1/8", as expected).  I don't have any 5/32" around but think that would work.

 

Next time I'm in Bellingham I'll stop by LFS and buy some Tenex.



#1313 thinwater

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Posted 08 April 2014 - 03:33 PM

soft_toggle_soft_toggle_13.jpg

 

It's amazing how Dyneema has taken us full circle. That's how I learned to attach the main halyard on my my first dingy, from a 1945 text. Soft shackle stropes, too (tied in hemp).



#1314 allen

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Posted 08 April 2014 - 03:44 PM

^^ Yes.  I found the method with a figure of eight stopper on yacht braid and then went looking for a button in a single line that I could bury to make it strong and work in Amsteel.  Everything builds on all that came before it.  The only difference is that the method in yacht braid had you thread the line first and then tie the stopper.  With the stopper permanent, you need the trick of reversing the loop to get the line on without passing the stopper through the hole.  One of the L-36.com readers came up with that trick.

 

Allen



#1315 Reht

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Posted 08 April 2014 - 04:01 PM

This is how I've been attaching halyards on boats from 420s to 49ers for years. Generally we just put on a reaonably large stopper ball instead of a permanent button knot (or equivalent)...



#1316 allen

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Posted 08 April 2014 - 04:26 PM

This is how I've been attaching halyards on boats from 420s to 49ers for years. Generally we just put on a reaonably large stopper ball instead of a permanent button knot (or equivalent)...

Just to clarify, the previous proposal for a halyard knot in Amsteel has 50% of the line strength and could not be untied.  This proposal should maintain full line strength and can be untied.  Most stopper knots slip and of course there would be loss of strength in the knot even if they did not slip.  Other than that, it is nothing new.



#1317 Reht

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Posted 08 April 2014 - 04:35 PM

I guess the doubling back with the tail makes it stronger, but when are you running your halyards at those kinds of loads? Anything new is progress, maybe it'll develop into something else!



#1318 Estar

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Posted 08 April 2014 - 04:35 PM

5mm dux . . . .1:1 bend radius . . . . broke at more than +95% of rated line strength (my load cell topped out at 10,000lbs and it broke a bit higher than that, with a rated strength of 10,472lbs), and at the taper (this was one of the 72 dim long bury/long tapers) rather than the bend.  I think we can say for certain that Dux is no more bend sensitive than amsteel, and most probably right on the bend graph we have.  

 

Attached File  photo 1.JPG   43.41K   5 downloads

 

Attached File  photo 2.JPG   60.74K   2 downloads

 

To make the bury's in this stuff, because it is so stiff and 'heat set' you have to disturb the braid more than you have to in softer line.  So I would guess (would need more pulls to be sure) that the bury/taper is both a little 'weaker' (as a % of rated strength, because you disturb the line 'set;) and more sensitive to technique than the softer dyneema lines.



#1319 allen

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Posted 08 April 2014 - 04:47 PM

I guess the doubling back with the tail makes it stronger, but when are you running your halyards at those kinds of loads? Anything new is progress, maybe it'll develop into something else!

I kind of line the look of the button rather than a stopper with a tail sticking out but the Estar stopper would work as it does not slip but would not be as strong.  But yes, mostly halyards do not get near breaking strength but stronger is always better, right?  There is some wear around the headboard so over time you might appreciate the extra strength.  Compared to just tying the Estar knot on the headboard, this can be untied, which was the main thing I was looking for initially.  You can use an eye splice and a toggle and I did that for a couple of years.  The problem with that is that the splice needs to be long so I was always fighting the extra thickness as I reversed the loop.  This button knot has a short splice so is easier to install.  Of course, the toggle was not a knot so it does not have to be untied.  Now I am using a tucked noose holding a soft shackle.  We shall see how that works this season.  This was just an idea I thought I would document and share.

 

Allen



#1320 Ishmael

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Posted 08 April 2014 - 04:49 PM

^^ Yes.  I found the method with a figure of eight stopper on yacht braid and then went looking for a button in a single line that I could bury to make it strong and work in Amsteel.  Everything builds on all that came before it.  The only difference is that the method in yacht braid had you thread the line first and then tie the stopper.  With the stopper permanent, you need the trick of reversing the loop to get the line on without passing the stopper through the hole.  One of the L-36.com readers came up with that trick.

 

Allen

 

I just can't see how this works with the standing end going up the mast. How do you get the loop around that? I must be having some brain fade today.



#1321 allen

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Posted 08 April 2014 - 04:53 PM

5mm dux . . . .1:1 bend radius . . . . broke at more than +95% of rated line strength (my load cell topped out at 10,000lbs and it broke a bit higher than that, with a rated strength of 10,472lbs), and at the taper (this was one of the 72 dim long bury/long tapers) rather than the bend.  I think we can say for certain that Dux is no more bend sensitive than amsteel, and most probably right on the bend graph we have.  

 

attachicon.gifphoto 1.JPG

 

attachicon.gifphoto 2.JPG

 

To make the bury's in this stuff, because it is so stiff and 'heat set' you have to disturb the braid more than you have to in softer line.  So I would guess (would need more pulls to be sure) that the bury/taper is both a little 'weaker' (as a % of rated strength, because you disturb the line 'set;) and more sensitive to technique than the softer dyneema lines.

As expected.  But that does leave the mystery unsolved.  Let us not forget that we have data that Dyneema scales at least from 1/8 to 3/4 so let's not go down that rabbit hole.  We have the heat theory for that one sample but wasn't there the assertion that samples with new line also failed at the terminator?  Maybe the solution is that the failures were all lines that had been in use for some time and heat is the cause of the excess weakness.

 

Allen



#1322 allen

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Posted 08 April 2014 - 04:56 PM

^^ Yes.  I found the method with a figure of eight stopper on yacht braid and then went looking for a button in a single line that I could bury to make it strong and work in Amsteel.  Everything builds on all that came before it.  The only difference is that the method in yacht braid had you thread the line first and then tie the stopper.  With the stopper permanent, you need the trick of reversing the loop to get the line on without passing the stopper through the hole.  One of the L-36.com readers came up with that trick.

 

Allen

 

I just can't see how this works with the standing end going up the mast. How do you get the loop around that? I must be having some brain fade today.

I think I must be getting senile as I seem to have documented how to do this several years ago.  This page shows how to attache the line with a stopper to the headboard fairly clearly.

 

http://L-36.com/halyard_stopper.php



#1323 Ishmael

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Posted 08 April 2014 - 05:02 PM

 

^^ Yes.  I found the method with a figure of eight stopper on yacht braid and then went looking for a button in a single line that I could bury to make it strong and work in Amsteel.  Everything builds on all that came before it.  The only difference is that the method in yacht braid had you thread the line first and then tie the stopper.  With the stopper permanent, you need the trick of reversing the loop to get the line on without passing the stopper through the hole.  One of the L-36.com readers came up with that trick.

 

Allen

 

I just can't see how this works with the standing end going up the mast. How do you get the loop around that? I must be having some brain fade today.

I think I must be getting senile as I seem to have documented how to do this several years ago.  This page shows how to attache the line with a stopper to the headboard fairly clearly.

 

http://L-36.com/halyard_stopper.php

 

Thanks. That makes sense. Duh.



#1324 rule69

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Posted 08 April 2014 - 05:27 PM

Not quite ready for prime time but maybe worth exploring if wire sheaves make tapers an issue:

 

Attached File  No taper halyard.png   631.86K   19 downloads

 

Pass the line through itself.

Move down a shackle length and pass the line through itself again to make the loop to hold the shackle knot.

Pass the tail through the first loop. 

Tie a noose around the standing parts back up towards the loop.

Tie a stopper knot in the tail.

 

Suspect it is knot strength rather than splice or shackle strength but it seemed reasonably stable when I put it on a winch.

 

I'm working with rope sheaves and I don't mind a splice going over them so I don't have a use for it but it is easy to tie, the knot doesn't need to pass through the headboard, and it is 1d at the sheave.



#1325 allen

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Posted 08 April 2014 - 05:38 PM

http://L-36.com/main_halyard_2.php

#1326 rule69

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Posted 08 April 2014 - 06:07 PM

^^^ Yes, but isn't that more complex to tie? And it has a bury in the tail that goes over the sheave.



#1327 allen

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Posted 08 April 2014 - 06:59 PM

^^ I was on my tablet and didn't see the passthrough detail to keep the knot from slipping.  Cleaver.  I wonder how strong it is.

 

Regarding the one I linked, one should use the Chinese button instead of the modified diamond. It can be tied with one end and is a little better knot as well.  I will update my documentation.



#1328 rule69

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Posted 08 April 2014 - 07:10 PM

 I wonder how strong it is.

I don't know. I put a 1/4" amsteel version on my winch and ground on to the "worried about breaking expensive hardware" point. I suspect it isn't super strong as a percent of the line though. Using Estar's trick of putting a core into the knot at the first look would probably make it a lot stronger.



#1329 allen

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Posted 08 April 2014 - 07:15 PM

^^ I know the feeling.  I crank on my winch until I am afraid I will die if something lets loose.  That is about 1000 pounds which would be 10% of the 1/4 inch line.  I can break 1/8 inch line if I am really careful, safety glasses, protective plywood, etc.  

 

I thought about the idea of inserting a core but by then it looks a lot like the one I already did and that one looks a little neater because burying the tail gets it out of the way.  I am assuming you are using an Estar stopper as most other stoppers slip although perhaps not at the loads this would see.

 

Allen



#1330 thinwater

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Posted 08 April 2014 - 07:17 PM

^^ Yes.  I found the method with a figure of eight stopper on yacht braid and then went looking for a button in a single line that I could bury to make it strong and work in Amsteel.  Everything builds on all that came before it.  The only difference is that the method in yacht braid had you thread the line first and then tie the stopper.  With the stopper permanent, you need the trick of reversing the loop to get the line on without passing the stopper through the hole.  One of the L-36.com readers came up with that trick.

 

Allen

 

Yup, that's the way I learned it! I still read that 1945 book occasionally, for the classic ideas that have been lost to the flood of manufactured goods.

 

My new mainsail comes by motor freight tomorrow (my first new sail in 10 years--yeah!); I've got the throw the SS shackle out and do it the old way, just 'cus.



#1331 thinwater

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Posted 08 April 2014 - 07:29 PM

I guess the doubling back with the tail makes it stronger, but when are you running your halyards at those kinds of loads? Anything new is progress, maybe it'll develop into something else!

...  There is some wear around the headboard so over time you might appreciate the extra strength.  ...

 

Allen

 

I've been testing cover materials for chafe resistance: nylon tubular webbing (9/16") is about  2 times more wear resistant than Amsteel (very different weave) and 8 times if treated with Maxijacket, and NER Dyneema Chafe Sleeve is about 50% more durable than that (not as thick as the nylon). Slipping some webbing over the eye is a light weight solution for headboards.



#1332 rule69

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Posted 08 April 2014 - 07:36 PM

I am assuming you are using an Estar stopper as most other stoppers slip although perhaps not at the loads this would see.

Yes, but a button with the tail tucked might look nicer. I think the knot will break at the 1st loop anyway.



#1333 Estar

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Posted 08 April 2014 - 07:37 PM

I had a bit of dux left after the break tests so made up two of the button bury soft shackles as practice.

 

Allen, I figured out where I was occasionally going wrong with the instructions. In the step where you bring the second tail up thru the second lobe, rather than taking the second tail under the first, I was taking it over.  This is clear in the pictures but not in the writing and is harder to see when the two tails are the same color.

 

I notice that you can set the buried tail lengths to constrain the noose opening, longer buries make a more constrained noose - that could prevent any (very small already) possibility of flogging loose.

 

For my anchor snubber use, I think I like my simplified 'loop stopper' better (despite it being asymmetrical) because you can more easily get the correct (short) length bury firmly locked into place.  The button one tends to end up with longer buries, which are too thick for the chain link.

 

Final comment . . . I would think the commercial guys (like John F and Brion) would like these 'stronger bury designs' because they clearly reward the ability to apply really significant pre-load.  Even the button likes to be strongly pre-loaded before the bury . . . to pull the extra length out of the knot and then get the buries firmly planted close to the knot.  I put 5000lbs on these before doing the bury.

 

Attached File  softbury.JPG   41.7K   15 downloads



#1334 allen

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Posted 08 April 2014 - 07:37 PM

 I think the knot will break at the 1st loop anyway.

agree.



#1335 Merit 25

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Posted 08 April 2014 - 07:57 PM

thin water

 

I have done a bunch with oscillating chafe for  Practical Sailor article, and I can give you the very short version, based upon 3/8" polyester DB and 1/4 Amsteel, all cycled against a grindstone (40degree angle). I'm still refining the numbers and running reps, so you might see slightly different numbers.

  • Polyester line cover fails in 1-3, line in 20-30 minutes.

  • Polyester cover with Maxijacket ran up to 20 minutes.

  • 5/32 wire failed in 20 min.

  • Amsteel ran 2 hours with ~ 30-40% chafe.

  • Leather--20 min

  • nylon tubular webbing -- 45 min

  • Dyneema chafe guard -- 55 min (the nylon is thicker!)

  • Nylon and Dyneema with Maxijacket -- over 2 hours

  • every other sort of plastic tubing -- a few minutes

  • APC cover -- 10-14 minutes

Really, several simple findings:

  • Wire fatigues

  • Webbing and covers are totally different, because of the difference in weave; a tubular webbing sleeve wears many times longer than a braided cover, regardless of the material.

  • Maxijacket is impressive, on lines, splices, and over chafe guards too.

I don’t understand your findings in bold above.  Seems like your conclusion contradicts your findings?  I must have misinterpreted this.

 

Edit: I re-read, are you saying that DCS is the "winner" here?



#1336 allen

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Posted 08 April 2014 - 11:21 PM

I had a bit of dux left after the break tests so made up two of the button bury soft shackles as practice.

 

Allen, I figured out where I was occasionally going wrong with the instructions. In the step where you bring the second tail up thru the second lobe, rather than taking the second tail under the first, I was taking it over.  This is clear in the pictures but not in the writing and is harder to see when the two tails are the same color.

I have made some edits to address this. Also found a number of typo's ( I can't spell).  I hope the revised test addresses the area where you had a concern.  

 

I notice that you can set the buried tail lengths to constrain the noose opening, longer buries make a more constrained noose - that could prevent any (very small already) possibility of flogging loose.

If you make the buried tails long enough, you might as well just go up a size and make the "Better Soft Shackle".  Going from 5/32 to 3/16 gives a similar increase in strength and a similar increase in weight.  I think these high strength shackles have a place, but I do not think they replace the standard ones.

 

For my anchor snubber use, I think I like my simplified 'loop stopper' better (despite it being asymmetrical) because you can more easily get the correct (short) length bury firmly locked into place.  The button one tends to end up with longer buries, which are too thick for the chain link.

 

This is a good example of a nice application for these higher strength shackles.

 

Allen



#1337 thinwater

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Posted 09 April 2014 - 12:17 AM

^^ My comment that "the nylon is thicker!" was to explain why Dyneema did not dramatically out-wear nylon; if the weave had been the same I'm sure it would have, but this specific tubular nylon product has a very thick, dense weave. My point was that weave and thickness matter as much as material.

 

Yes, the Dyneema sleeve wore a little better and was significantly thinner, which could matter... or not. Add a little Maxijacket and you'll sell the boat first--literally 100x better than polyester.



#1338 Estar

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Posted 09 April 2014 - 12:16 PM

If you make the buried tails long enough, you might as well just go up a size and make the "Better Soft Shackle".  Going from 5/32 to 3/16 gives a similar increase in strength and a similar increase in weight.  I think these high strength shackles have a place, but I do not think they replace the standard ones.
Allen


I don't see myself ever making a "traditional" one again. When I make them I always have tails to cut off and throw again. With these new ones, rather than wasting that material, it is incorporated as extra strength (and makes the knot neater). The button is really not more difficult than the diamond. And I don't really care about the "one strand body" but if someone does, with the new ones you can just sew the two strands together. I don't see any downside at all to the new designs, only upside (stronger, neater).

So we can agree to disagree on this. For most uses I will make a button bury (because of the nicer looking knot), but a loop bury for those specific applications where I need a really short firmly bedded bury.

^^ My comment that "the nylon is thicker!" was to explain why Dyneema did not dramatically out-wear nylon; if the weave had been the same I'm sure it would have, but this specific tubular nylon product has a very thick, dense weave. My point was that weave and thickness matter as much as material.


Are you using a particular, specific nylon webbing? Brand, model, source - curious about sizing options.

Have you factored in that nylon is weaker when wet?

Have you factored in nylon is more UK sensitive than either polyester or dyneema?

#1339 allen

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Posted 09 April 2014 - 03:16 PM

So we can agree to disagree on this. For most uses I will make a button bury (because of the nicer looking knot), but a loop bury for those specific applications where I need a really short firmly bedded bury.

I do think all kinds have their place.  My interest is to hold on jib sheets and for that my main decision criteria is ease of use.  I really have no interest in using 1/8 Amsteel shackles against 7/16 sheets as I worry about strength loss in the XLS from the small bend radius.  5/32 Shackles are way stronger than the sheets according to your measurements so no need to make them stronger.  So, I accept your conclusion on agreeing to disagree.

 

Regarding the button stronger shackles.  If you tie the buttons and stitch the bury (which I will add to my write up) won't the two ends tighten equally upon loading up the button so that pre-tensioning is more an issue of controlling the length?  You can't suck the tails in like in a normal diamond knot if the bury is long enough so that is an advantage. Perhaps that would require a longer bury.  Have you tested that?

 

The other issue, of course, is that you have a way to put 5000 pounds on the button before you do the bury.  Thus your comment about this being a nice candidate for a commercial house to produce.  The flip side is that I have a nice way to set a normal diamond knot that is not possible with the button.

 

Allen



#1340 thinwater

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Posted 09 April 2014 - 09:18 PM

If you make the buried tails long enough, you might as well just go up a size and make the "Better Soft Shackle".  Going from 5/32 to 3/16 gives a similar increase in strength and a similar increase in weight.  I think these high strength shackles have a place, but I do not think they replace the standard ones.
Allen


I don't see myself ever making a "traditional" one again. When I make them I always have tails to cut off and throw again. With these new ones, rather than wasting that material, it is incorporated as extra strength (and makes the knot neater). The button is really not more difficult than the diamond. And I don't really care about the "one strand body" but if someone does, with the new ones you can just sew the two strands together. I don't see any downside at all to the new designs, only upside (stronger, neater).

So we can agree to disagree on this. For most uses I will make a button bury (because of the nicer looking knot), but a loop bury for those specific applications where I need a really short firmly bedded bury.

>^^ My comment that "the nylon is thicker!" was to explain why Dyneema did not dramatically out-wear nylon; if the weave had been the same I'm sure it would have, but this specific tubular nylon product has a very thick, dense weave. My point was that weave and thickness matter as much as material.


Are you using a particular, specific nylon webbing? Brand, model, source - curious about sizing options.

Have you factored in that nylon is weaker when wet?

Have you factored in nylon is more UK sensitive than either polyester or dyneema?

 

 

I have not tested wet. Good point, I will re-test all products wet. However, if coated with Maxijacket I will go out on a limb and say it won't matter.

 

The webbing is Blue Water Climb-Spec, available at any REI. That said, the weave is different for each size and I have not yet tested 1" and 2"; I've used them as chafe guards for 25 years, but I have not tested them with this protecole.

 

UV testing will take years. I have samples in the sun. However, I've used this stuff for 10 years at a click before; I think the difference will not be so great, certainly not in the contact area, which will not see much sun (I have seen this effect--generally the contact area is not faded). Though nylon does degrade somewhat  more quickly (not fast like polypro), the difference will likely only be important in years 5-10. I know I have used nylon for thimbles and docklines, and it always out-lasted the line.

 

Bottom line: Dyneema chafe sleeve is the better choise in sizes where it is available. The point of the demonstration is to illustrate that the weave is critically important to chafe, more important than the material; a Dyneema webbing sleeve is not in the same catagory as a Dyneema cover, etc.



#1341 Estar

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Posted 09 April 2014 - 09:57 PM

^^ I have been using 2.5" fire hose, over 3/4" line. I was just curious if this nylon webbing came in something like that size. I use about yard long pieces and find it hard with smaller hose to thread/slide to the right spot. I don't tie up to the same dock, so need to move/adjust the house pretty much every time. . . The nylon might slide easier than the fire hose.

For this same reason I suspect the hose will get evenly UV cooked, and the contact section not protected. But I don't know how revelant UV weakness is to whatever property is in play with chafe protection -I suppose it is not tensile that is important.

#1342 thinwater

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Posted 10 April 2014 - 12:17 AM

^^ I use 2" tubular webbing over 5/8" docklines. When everything is new it will slide over the splices, but that becomes difficult with age. The fit over the line is very loose and 3/4" would be easy. Yes, it slides fast, even with age.



#1343 Estar

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Posted 10 April 2014 - 02:05 AM

By the way, here is a bit of rope work that could use some development.

Attached File  image.jpg   23.98K   26 downloads

It is the key component in the twizzle rig.

#1344 rule69

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Posted 10 April 2014 - 08:23 PM

What's a twizzle rig?

 

On the subject of things that could use development:

Attached File  whoopie sling bail.png   909.69K   17 downloads

I made this up to use to float a block under a boom. The block gets installed and removed each sail. It needs to be a little snugger than is easy with a normal soft shackle. Strength isn't an issue but fiddliness is. We've been using string but the crew's knotting skills are variable. This bypasses the knots but it is fiddly. Is there a better way?

 

 



#1345 allen

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Posted 10 April 2014 - 09:09 PM

^^That looks most ingenious. Can you break the problem into two parts with a large simple softshackle for strength and some Velcro to snug it up?

Allen

#1346 rule69

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Posted 10 April 2014 - 09:21 PM

^^^ They already know velcro, so that's a good starting place. Thanks for the idea.

 

Maybe I can get away with a bit of bungee cord inside the shackle in this application. I'll think about that too.



#1347 Presuming Ed

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Posted 10 April 2014 - 10:38 PM

What's a twizzle rig?


Twin poled out jibs.

http://www.simetric....e_rig/index.htm

#1348 rule69

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Posted 10 April 2014 - 10:54 PM

^^^ Cheers.



#1349 allen

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Posted 11 April 2014 - 01:39 AM

Semi new topic. A Brummel eye splice can be made using just one end with the McDonald Brummel. There is another method that is not "correct" that is a lot easier. Take the working and and pass it through the standing end. That makes a loop. Make a hole in the working end and away from the loop. Pass the loop through that hole. Pull it out. That will look like a Brummel but some of the fibers are twisted. Now bury the working and and taper normally. Is it as strong? Does it matter that the fibers are twisted?

Allen

#1350 Pelle

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Posted 11 April 2014 - 04:39 AM

Semi new topic. A Brummel eye splice can be made using just one end with the McDonald Brummel. There is another method that is not "correct" that is a lot easier. Take the working and and pass it through the standing end. That makes a loop. Make a hole in the working end and away from the loop. Pass the loop through that hole. Pull it out. That will look like a Brummel but some of the fibers are twisted. Now bury the working and and taper normally. Is it as strong? Does it matter that the fibers are twisted?
Allen

Can't it be untwisted by passing the working end back through the hole before making the bury? Or am i not thinking straight?

#1351 allen

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Posted 11 April 2014 - 05:04 AM

^^yes. That is the McDonald Brummel but I always have to look up which way to pass the tail through.

#1352 allen

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Posted 11 April 2014 - 05:19 AM

I would be surprised if you can get the 3/8 Tenex inside the 3/16 Amsteel.  Salsa braid and Tenex look the same except for the color so maybe you can.    I had a difficult time getting half the tenex inside my Amsteel but that was probably 5/32.  As a backup, you can bury half the strands of the Tenex and bury a long section of the Amsteel.  Please let us know how it works out.

 
I played with it at home today using new line.  I don't have Tenex, but I have some NERopes Regatta Braid which I think may be similar?  It is a single braid 12-strand dacron rope that is a bit bulkier than Salsa Braid.
 
1/4" dyneema with 3/8" regatta braid:
13708532545_5f90d7802d_z.jpg
 
That was pretty easy, I think it might be easier than putting an eye splice into the Regatta Braid.  Buries are a little short since I just did this as a test and don't intend to use it.
 
I tried 3/8" Regatta Braid to 3/16" dyneema, but couldn't get the bury to work.  5/16" to 3/16" probably would.
 
I was curious to see how far I could taper this down in another step.  1/4" dyneema to 3/16" dyneema was easy, 1/4" to 1/8" didn't work (I couldn't fit the 1/4" into the 1/8", as expected).  I don't have any 5/32" around but think that would work.
 
Next time I'm in Bellingham I'll stop by LFS and buy some Tenex.

Just for completeness, the standard way to splice dissimilar lines like this is back to back eye splices. That might work for this application so just wanted to make sure you considered it.

Allen

#1353 rule69

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Posted 11 April 2014 - 05:38 AM

^^^ FWIW, 1/4 amteel splices with 3/8 tenex like that. I think I will keep a long tail of amsteel  in the splice so that the doubled line goes through the rope clutch at all the reef positions. "The Plan" is a brummell splice and ess stitching.



#1354 allen

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Posted 11 April 2014 - 02:29 PM

^^ You could splice 1/8 Amsteel to 1/2 Tenex that way if you wanted to. The drawback is that the larger line gets get pretty thick so it isn't a very smooth joint.

Your idea of a series of decreasing diameters of Amsteel is actually pretty nice.

Allen

#1355 Estar

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Posted 11 April 2014 - 11:43 PM

I have added a "Hybrid" version of the EStar to my instructions (see after the regular version instructions) . . . This is about 95% of line strength (depending on bury taper and length).  It is more work to tie and you would probably not want to do it on the foredeck, but it is still pretty simple, and allows you a shorter bury length than a standard buried loop.



#1356 Alex W

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Posted 11 April 2014 - 11:59 PM

Just for completeness, the standard way to splice dissimilar lines like this is back to back eye splices. That might work for this application so just wanted to make sure you considered it.

 

How well does that work when passing over a block?  The end to end brummel works pretty well.  Two linked eye splices seems like it wouldn't be as smooth.



#1357 allen

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Posted 12 April 2014 - 03:45 AM

^^i have never tried it but it is the recommended method for lines with different stretch characteristics.

Allen

#1358 Reht

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Posted 12 April 2014 - 04:03 AM

^^i have never tried it but it is the recommended method for lines with different stretch characteristics.

Allen

Makes sense if you're running the lines at loads that will cause a bit of stretch... I wonder if a well done eye-in-eye splice could have the cover dragged back over it or if the inner bulk of the doubled core would make it impossible...



#1359 allen

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Posted 12 April 2014 - 09:33 PM

I have added a "Hybrid" version of the EStar to my instructions (see after the regular version instructions) . . . This is about 95% of line strength (depending on bury taper and length).  It is more work to tie and you would probably not want to do it on the foredeck, but it is still pretty simple, and allows you a shorter bury length than a standard buried loop.

I like this hybrid quite a lot.  One nice thing is that a lot of the buried section goes around the shackle so that I assume less of the thicker section would go up toward the sheave.  Given that really the only reason to use this instead of a splice is to keep that distance at a minimum.  @Estar, have you measured how long the buried section needs to be?  I assume it needs zero length in excess of the knot to not slip but how much does it need to gain the extra strength?

 

Allen



#1360 Estar

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Posted 13 April 2014 - 12:23 AM

I have added a "Hybrid" version of the EStar to my instructions (see after the regular version instructions) . . . This is about 95% of line strength (depending on bury taper and length).  It is more work to tie and you would probably not want to do it on the foredeck, but it is still pretty simple, and allows you a shorter bury length than a standard buried loop.

I like this hybrid quite a lot.  One nice thing is that a lot of the buried section goes around the shackle so that I assume less of the thicker section would go up toward the sheave.  Given that really the only reason to use this instead of a splice is to keep that distance at a minimum.  @Estar, have you measured how long the buried section needs to be?  I assume it needs zero length in excess of the knot to not slip but how much does it need to gain the extra strength?

 

Allen

I tested one with 10 dia's stocking out - with the bury sewn, and it was strong, broke at the 'cover' (eg the outer part of the bury) at the entrance to the knot.  I tested one with 10 dias, with no sewing, and it was down to 70% of line strength.

 

In one regard it is structurally less good than your noose because the loaded portion is near the standing part and the load is not bleed off, but in another structural regard it is better because there are two strands around the bend so it will not break at the hardware bend.

 

By the way, Grog suggested these  . . . http://www.animatedk...alian/index.php and http://www.animatedk...imini/index.php . . . and they do test well, better than 50%, but I really am not a fan of the 'lots of twists' school of knots.



#1361 allen

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Posted 13 April 2014 - 01:06 AM

 

I have added a "Hybrid" version of the EStar to my instructions (see after the regular version instructions) . . . This is about 95% of line strength (depending on bury taper and length).  It is more work to tie and you would probably not want to do it on the foredeck, but it is still pretty simple, and allows you a shorter bury length than a standard buried loop.

I like this hybrid quite a lot.  One nice thing is that a lot of the buried section goes around the shackle so that I assume less of the thicker section would go up toward the sheave.  Given that really the only reason to use this instead of a splice is to keep that distance at a minimum.  @Estar, have you measured how long the buried section needs to be?  I assume it needs zero length in excess of the knot to not slip but how much does it need to gain the extra strength?

 

Allen

I tested one with 10 dia's stocking out - with the bury sewn, and it was strong, broke at the 'cover' (eg the outer part of the bury) at the entrance to the knot.  I tested one with 10 dias, with no sewing, and it was down to 70% of line strength.

 

In one regard it is structurally less good than your noose because the loaded portion is near the standing part and the load is not bleed off, but in another structural regard it is better because there are two strands around the bend so it will not break at the hardware bend.

 

By the way, Grog suggested these  . . . http://www.animatedk...alian/index.php and http://www.animatedk...imini/index.php . . . and they do test well, better than 50%, but I really am not a fan of the 'lots of twists' school of knots.

 

Try the noose but instead of tucking the working end back under the knot and then doing the bury, bury it in the bright (with the loop open) away from the noose before the loop is closed so that it will be pulled back into the noose as the loop is tightened.  I think that is what I did on my halyard as I had to use a winch to get the loop to close as the thickened line was difficult to get  into the tightening noose.

 

I can do some pictures if I am being unclear.

 

Allen



#1362 rule69

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Posted 13 April 2014 - 02:07 AM

^^^ Is the motivation to avoid a splice just to keep the diameter over the sheave down? Seems that these tucked constructions use about the same amount of string and sweat as a splice.



#1363 allen

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Posted 13 April 2014 - 02:49 AM

^^  The length of the bury is much shorter as the force trying to make it slip is so much less because of the knot.  For example, the recommended length of a splice is around 60 diameters although 28 might be enough.  With these hybrids, around 10 diameters seems safe with 6 perhaps the lower limit.



#1364 nroose

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Posted 13 April 2014 - 03:43 AM

So, this is essentially the strength of a splice with shorter bury?

 

Seems like a replacement for a splice rather than a replacement for a knot, since it can't really be untied.

 

Perhaps call it the "EStar Splice"?

 

Looks like great work to me, anyway!

 

Thank you all again for all the great work!



#1365 Estar

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Posted 13 April 2014 - 11:55 AM

^^

I have been calling this class of things "hybrids" (part knot and part splice).

I personally don't have much use for the estar hybrid, but I knew Allen was looking for short bury solutions. It is potentially useful for applications where you don't want a bury to jam in a sheave or jaw (say a halyard or spin guy). My own lines are so over strength that the knot version is more than strong enough and easier, with zero bury.

#1366 allen

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Posted 13 April 2014 - 02:53 PM

^^ I do have a wire sheave which is very narrow so need to keep any bury short.  A knot is probably fine but stronger seems better.  In addition, I like getting the end of the line buried to get it out of the way an protect it from unraveling.



#1367 rule69

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Posted 13 April 2014 - 06:59 PM

^^  The length of the bury is much shorter as the force trying to make it slip is so much less because of the knot.  For example, the recommended length of a splice is around 60 diameters although 28 might be enough.  With these hybrids, around 10 diameters seems safe with 6 perhaps the lower limit.

I was thinking that the length of the sting used for the knot plus the bury must be approaching the amount of line used in a splice.

 

So, hybrid v splice:

 

Advantages:

 

In halyard use the knot replaces a ball if you need one.

 

Tucking the tail likely makes the knot less likely to catch.

 

The standing part is 1d.

 

Costs:

 

Involves both a knot and a splice.

 

May be hard to set properly with hand strength.

 

Takes the space of a halyard ball when you don't need one (ie. when hoisting closer to the sheave is desired).



#1368 thinwater

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Posted 14 April 2014 - 07:28 PM

 

If you make the buried tails long enough, you might as well just go up a size and make the "Better Soft Shackle".  Going from 5/32 to 3/16 gives a similar increase in strength and a similar increase in weight.  I think these high strength shackles have a place, but I do not think they replace the standard ones.
Allen


I don't see myself ever making a "traditional" one again. When I make them I always have tails to cut off and throw again. With these new ones, rather than wasting that material, it is incorporated as extra strength (and makes the knot neater). The button is really not more difficult than the diamond. And I don't really care about the "one strand body" but if someone does, with the new ones you can just sew the two strands together. I don't see any downside at all to the new designs, only upside (stronger, neater).

So we can agree to disagree on this. For most uses I will make a button bury (because of the nicer looking knot), but a loop bury for those specific applications where I need a really short firmly bedded bury.

>^^ My comment that "the nylon is thicker!" was to explain why Dyneema did not dramatically out-wear nylon; if the weave had been the same I'm sure it would have, but this specific tubular nylon product has a very thick, dense weave. My point was that weave and thickness matter as much as mat

erial.

Are you using a particular, specific nylon webbing? Brand, model, source - curious about sizing options.

Have you factored in that nylon is weaker when wet?

Have you factored in nylon is more UK sensitive than either polyester or dyneema?

 

I have not tested wet. Good point, I will re-test all products wet. However, if coated with Maxijacket I will go out on a limb and say it won't matter....

 


 

 

I've never really thought too much about nylon chafe when wet, since it didn't apply to my experience; my mooring lines are well-protected, my anchor rode is chain, and my bridle rigged from cleats with good chafe protection (I suspect this is generally less of a problem for cats--we must always use bridles, but they are easier to rig chafe-free).

 

Wet vs. Dry Chafe

(2 reps each, only a few minutes variation)

 

Material                                    Wet vs Dry      Time to Chafe Through

Nylon webbing                          Dry                  45 min.

Nylon webbing                          Wet                 14 min.

NER Dyneema chafe sleeve    Dry                   50 min.

NER Dyneema Chafe Sleeve   Wet                  40 min.

 

I expected a difference, but 3x caught me by surprise. It is more than a simple change in strength, probably beyond simple analysis. I need to see how much difference Maxijacket makes; there are applications like chain-to-rope splices where Dyneema's not an option. I'll also expand this to include ropes and polyester.

 

The nylon webbing still makes sense many places, where availability in large sizes and price matter. For comparison, the cover on a typical line fails in 1-3 minutes.



#1369 Estar

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Posted 14 April 2014 - 08:00 PM

>>Nylon webbing                          Dry                  45 min.
>>Nylon webbing                          Wet                 14 min.
 
Wow . . . I had expected perhaps a 20% difference.  Is this fresh water wet or salt water wet - eg is the salt abrading the nylon or is it all pure water effect?
 
>>NER Dyneema chafe sleeve    Dry                   50 min.
>>NER Dyneema chafe Sleeve   Wet                  40 min
 
Even that surprises me.  The literature clearly says that nylon changes when wet, but it also suggested that dyneema does not (meaningfully)
 
The big 'wet' application is protecting para-anchor and drogue rodes.  The most common failure mode is rode chafe, and usually it is in conditions when everything is getting wet.


#1370 thinwater

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Posted 14 April 2014 - 09:09 PM

^^ All of the tests were repeated (wet and dry).

 

Fresh water only.

 

Yup, there is clearly something complicated going on.



#1371 Ishmael

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Posted 14 April 2014 - 09:13 PM

From another angle, sharpening blades on a dry stone is much slower than on a wet stone. Maybe there is a similar "slurry" produced by the water which carries away abraded particles to expose fresh surfaces.



#1372 thinwater

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Posted 14 April 2014 - 09:42 PM

^^ Yes, something like that. Some things are best determined through testing!

 

I've coated some strips of Sunbrella polyester sail cloth with Maxijacket; I'm curious what it might do there. I have also coated some webbing with Maxijacket; it increased the wear significantly dry, and might make even greater difference wet...

 

Which brings us to the question of ground tackle and drogues. Maxijacket did some amazing things for polyester double braid and small nylon 3-strand (5x wear, as deep as it can soak in, which is pretty deep) dry, but I didn't test it wet. However, I know some riggers and Defender are specing it for all rope to chain splices. I've coated some more webbing and will get us some numbers in 2 weeks (it takes that long to reach full effectiveness, just as latex paint dries fast but hardens slow). I've only used a drogue once, and it was a matter of intentionally slowing to delay arrival rather than strong conditions.

 

What I can't test is whether is any detrimental affect when cycled at high load. I think it unlikely, but I just don't know. I did test it for strength reduction on nylon, polyester, and Dyneema; no change. While it does stiffen the line a good bit, there might be an application, depending on where the chafe is.



#1373 Estar

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Posted 15 April 2014 - 12:30 PM

Wire seizing (this is all aircraft .041 stainless lockwire):

 

The 'conventional method' - two loops and then twist the ends 8 times - the twist comes apart at 450lbs

 

Attached File  s1.JPG   55.01K   1 downloads

 

In order to reduce the load on the twist, I then tried taking two turns around the seizing before twisting the ends.  But this does not allow the seizing legs to equalize load and the wire broke at 420lbs.

 

Attached File  s2.JPG   54.24K   1 downloads

 

In order to allow more equalization I just took one turn around the seizing before the twist.  This was better - wire broke at 470lbs

 

Attached File  s3.JPG   44.38K   1 downloads

 

In order to allow complete equalization while still taking some load off the twist I took a turn around one end before the twist.  This broke at 500lbs - it is the best structural solution.

 

Attached File  s4.JPG   55.55K   1 downloads

 

Just for knowledge I did the above but with 3 loops - broke at 840lbs

 

Attached File  s6.JPG   54.91K   1 downloads



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Posted 15 April 2014 - 12:57 PM

Duplicate post from the tramp thread, just to capture it here

 

Two loops of webbing (inexpensive stuff - 2700lb), with 4 stitches of dyneema fishing line thru the middle - stitching pulled thru the webbing at 1370 lbs.  Could obviously be made stronger with more stitches (or firmer webbing), but the idea was something that was fast and not too much work.

 

Attached File  w2.JPG   58.23K   1 downloads



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Posted 15 April 2014 - 06:04 PM

Duplicate from outhaul thread . . . 
 
ok, velcro . . . 
 
This is "genuine Velcro brand, made in USA", I bought at WM, which is not a 3m product, and appears to be weaker than the 3m product.  So, first lesson is that there are differences in strength between the various hook and loop products.
 
I pulled between two shackles.
 
A straight line shear pull (eg no loops) I got 7.5 psi
 
A "2-wrap" I got 45 psi (6X the straight line - I 'expected' a bit more than 4x, and got +2x more)
 
A "3 wrap" I got 70 psi (9.3x the straight line - I 'expected' a bit more than 6x, and got +3.3x more)
 
So, it would appear there is a lot of advantage to the first loop, probably because it puts a compression friction loading on the velcro, and then significant but diminishing returns to further loops.
 
Extrapolating a bit - A 6' webbing piece made into a 3-wrap loop, of the 3m tape, should then be 72 sq in x 14psi x 9.3 =  9400lbs (if the 14psi spec is correct - I have some on order to test/confirm).
 
If I have this right . . . . That's pretty damn strong, dyneema soft shackle country - surprised these are not used in more applications.
 
As thinwater mentioned the failure mode is also nice . . . a very slow creep, rather than just letting go.


#1376 Estar

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Posted Yesterday, 12:51 AM

velcro . . . . some people cleat off one end of their jacklines (I have in the past) . . . . might make good sense to sew velcro on that end . . . . not necessarily to take the primary load, which the cleat will do, but for 'extra security' and to stop any slipping (or accidental uncleating).  It's cheap and easy, and might help sometime.






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