Cruisers Forum
 


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 22-01-2022, 21:56   #1
Registered User

Join Date: Aug 2021
Location: Houston Texas
Boat: None
Posts: 8
A simpler soft shackle knot

I should start by saying thanks to the greater community here for all the education you have all shared with me.

One of the topics that has interested me greatly is the use of modern materials to create soft shackles. I have recently purchased some dyneema and I am playing around with them.

Professionally, my work has led me to be a student of Human Performance (sometimes called Human Factors), in short it's the study how people interact with their systems or environments with a focus on how to reduce error rates around critical steps and improve the resilience of systems by working to reduce the consequence of failure when (not if) it will occur.

As I have been making soft shackles, particularly tying the button or diamond knot I'm looking at the spaghetti in my hand thinking that I'm in a situation where error is likely and the consequences of my error may by difficult to mitigate. I recognize that with practice the knots will become easier, however I'm not convinced that the likelihood of error will reduce by an order of magnitude or more.

I recently watched a video of shackles made using a much simpler overhand knot where the tails are buried and the shackle is fed through the loops created by the bury to tie the knot together. During the testing it appeared that the knot was not the failure point.

The referenced video can be found here



I would appreciate the collective thoughts about the pros and cons of taking this approach to create a (perhaps less error prone) shackle.

I'd like to be clear that I'm not in any way denigrating the current shackle designs, I'm just wondering if there is an alternative that may maintain the benefits of the current shackles that would be simpler to tie for newer or less dexterous folks.
Renoirpierre is offline   Reply With Quote
Old 23-01-2022, 00:04   #2
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,168
Re: A simpler soft shackle knot

Probably strong enough, but they sure are fugly!
StuM is offline   Reply With Quote
Old 23-01-2022, 01:16   #3
Moderator
 
Seaworthy Lass's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Boat: Bestevaer 49
Posts: 15,800
Re: A simpler soft shackle knot

Quote:
Originally Posted by Renoirpierre View Post
I should start by saying thanks to the greater community here for all the education you have all shared with me.

One of the topics that has interested me greatly is the use of modern materials to create soft shackles. I have recently purchased some dyneema and I am playing around with them.

Professionally, my work has led me to be a student of Human Performance (sometimes called Human Factors), in short it's the study how people interact with their systems or environments with a focus on how to reduce error rates around critical steps and improve the resilience of systems by working to reduce the consequence of failure when (not if) it will occur.

As I have been making soft shackles, particularly tying the button or diamond knot I'm looking at the spaghetti in my hand thinking that I'm in a situation where error is likely and the consequences of my error may by difficult to mitigate. I recognize that with practice the knots will become easier, however I'm not convinced that the likelihood of error will reduce by an order of magnitude or more.

I recently watched a video of shackles made using a much simpler overhand knot where the tails are buried and the shackle is fed through the loops created by the bury to tie the knot together. During the testing it appeared that the knot was not the failure point.

The referenced video can be found here

……..

I would appreciate the collective thoughts about the pros and cons of taking this approach to create a (perhaps less error prone) shackle.

I'd like to be clear that I'm not in any way denigrating the current shackle designs, I'm just wondering if there is an alternative that may maintain the benefits of the current shackles that would be simpler to tie for newer or less dexterous folks.
Hi RenoirPierre
Welcome to CF.

Using an overhand knot as shown in the video was first described by Evans Starzinger at least 6-7 years ago. He called it an “improved” soft shackle. Several members here are successfully making their soft shackles using this technique.

Evans reported that, if well made, the strength of these is similar to other “high strength” designs where the tails are buried in the legs: ie approx 230-240% of line strength. He cautioned only to make the eyes that were used to form the knot as small as possible otherwise there was a risk of the knot capsizing under load. Videos I have seen explaining this technique don’t seem to mention this.

SWL
__________________
SWL (enthusiastic amateur)
"To me the simple act of tying a knot is an adventure in unlimited space." Clifford Ashley
"The cure for anything is salt water: sweat, tears or the sea." Isak Dinesen

Unveiling Bullseye strops for low friction rings
Seaworthy Lass is offline   Reply With Quote
Old 23-01-2022, 19:56   #4
Registered User

Join Date: Aug 2021
Location: Houston Texas
Boat: None
Posts: 8
Re: A simpler soft shackle knot

Thanks for the replies SWL and StuM.

Other than watching the eye sizes, are there any downsides to the "improved" design over the better, BB, or strong?

Thanks

RP
Renoirpierre is offline   Reply With Quote
Old 23-01-2022, 20:18   #5
Moderator
 
Seaworthy Lass's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Boat: Bestevaer 49
Posts: 15,800
Re: A simpler soft shackle knot

Quote:
Originally Posted by Renoirpierre View Post
Thanks for the replies SWL and StuM.

Other than watching the eye sizes, are there any downsides to the "improved" design over the better, BB, or strong?

Thanks

RP
Not that I am aware of. The stopper does look a bit clunky, but beauty is in the eye of the beholder . The larger than usual stopper knot may actually be advantageous at times.

Care must be taken with the construction of all soft shackles to gain maximum strength. I think the above design contains, if anything, fewer opportunities to make errors. It is relatively easy to make if rope work skills are not high.

When making these here are a few tips from me to help maximise potential strength:
- Make sure the main eye at the end (that secures the shackle closed) is not a noose. Personally, I would make this large enough to hold 6-8 x the dimeter of the line (4 lots of line will actually be passing through it, as the tails are buried in that segment).
- Secure the eye size with tape while working so that it does not shift inadvertently.
- Ensure the two legs are absolutely an identical length when the bury is completed before the knot is tied. If they are not, when the knot is tensioned the size of the main eye could alter.
- Don’t twist the line during construction.
- Use the usual techniques to tension the finished shackle carefully by hand, then pretension under load (eg using a winch) and leave to sit for 20-30 minutes with the load applied. Strength can diminish significantly if shock loads are applied before this is done.

Edited to add: After the main eye is formed and secured with tape, trim the ends so that the length of the two legs is identical. Although any excess will be buried, the difference in bury length will alter the final length of the leg as the outer portion bunches up when filled. By far the easiest way to avoid this is to initially trim.

Have fun making these.

SWL
__________________
SWL (enthusiastic amateur)
"To me the simple act of tying a knot is an adventure in unlimited space." Clifford Ashley
"The cure for anything is salt water: sweat, tears or the sea." Isak Dinesen

Unveiling Bullseye strops for low friction rings
Seaworthy Lass is offline   Reply With Quote
Old 23-01-2022, 21:57   #6
Moderator
 
Jim Cate's Avatar

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 19,562
Re: A simpler soft shackle knot

Quote:
Use the usual techniques to tension the finished shackle carefully by hand, then pretension under load (eg using a winch) and leave to sit for 20-30 minutes with the load applied. Strength can diminish significantly if shock loads are applied before this is done.
Ange,do you know why this is? Seems kinda odd...

Jim
__________________
Jim and Ann s/v Insatiable II, still hanging out in Port Cygnet. Summer was nice... it was on a Tuesday... and now autumn is here and being pretty nice so far!
Jim Cate is offline   Reply With Quote
Old 23-01-2022, 22:46   #7
Moderator
 
Seaworthy Lass's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Boat: Bestevaer 49
Posts: 15,800
Re: A simpler soft shackle knot

Quote:
Originally Posted by Jim Cate View Post
Ange,do you know why this is? Seems kinda odd...

Jim
I think that it occurs (at least partly) because sudden loads will cause the line in the knot to move very rapidly when it tightens up, heating it. The melting point of UHMWPE is relatively low: roughly 140-150C so damage to the line can occur with this rapid movement, weakening it.

Someone else may chime in with more inform regarding this.
__________________
SWL (enthusiastic amateur)
"To me the simple act of tying a knot is an adventure in unlimited space." Clifford Ashley
"The cure for anything is salt water: sweat, tears or the sea." Isak Dinesen

Unveiling Bullseye strops for low friction rings
Seaworthy Lass is offline   Reply With Quote
Old 24-01-2022, 05:12   #8
Registered User

Join Date: Aug 2021
Location: Houston Texas
Boat: None
Posts: 8
Re: A simpler soft shackle knot

I appreciate the warm welcome and the informative response. I'll go make a couple and come back if I have any questions.

RP
Renoirpierre is offline   Reply With Quote
Old 24-01-2022, 10:34   #9
Registered User

Join Date: Apr 2019
Posts: 1,287
Re: A simpler soft shackle knot

Quote:
Originally Posted by Renoirpierre View Post
I appreciate the warm welcome and the informative response. I'll go make a couple and come back if I have any questions.

RP
The buried tail button design is (imho) the best of the 'stronger' designs. It has essentially no failure mode; while the overhand does have the 'collapse mode' if loops not sized correctly; and the diamond has 'pull apart' if allowed to suck in its tails.

In theory, the button and overhand are the same strength. In actual testing the overhand may be very tiny bit stronger - but practically speaking they are the same strength.

The button is relatively easy to make once you have made one, and SLW here has written quite good instructions for it. The overhand is easier to learn the first one, but after you have made a few they are about the same difficulty.

And the button is better looking.

If I were you, I would learn to make buried buttons.
Breaking Waves is offline   Reply With Quote
Old 24-01-2022, 18:37   #10
Navigator
 
SeanPatrick's Avatar

Cruisers Forum Supporter

Join Date: Dec 2012
Location: Norfolk, VA USA
Posts: 550
Re: A simpler soft shackle knot

I've used a lanyard knot (a.k.a. diamond knot) in combination with a butterfly loop to make expedient soft shackles. Both knots are relatively easy to tie IMO. I leave the working ends, which I have kept to a minimum while working the lanyard knot tight, sticking out of the "top" of the knot. They don't seem to get in the way too much. I make the butterfly loop just big enough to be able to get around the lanyard knot with a little coaxing.

NB: I have never used this particular arrangement for high loads, so I'm not sure of its suitability for such a purpose.
__________________
If you have any questions about celestial navigation, ask me!
Celestial Navigation Spreadsheet


NavList Celestial Navigation Forum: fer3.com/arc
SeanPatrick is offline   Reply With Quote
Reply

Tags
knot

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Instructions for Tying the Brion Toss Button Knot & High Strength Soft Shackle Seaworthy Lass Deck hardware: Rigging, Sails & Hoisting 131 16-05-2022 14:44
Americas Cup and simpler days sailingabe41ds General Sailing Forum 202 08-02-2021 14:29
Cruising - Is it a Simpler Life ? Bo English Meets & Greets 34 28-01-2021 22:08
Soft Shackle vs Bow Shackle StoneCrab Deck hardware: Rigging, Sails & Hoisting 3 17-09-2020 03:26
skydiving soft link (slink) soft shackle alternative Breaking Waves Deck hardware: Rigging, Sails & Hoisting 5 16-07-2020 16:43

Advertise Here


All times are GMT -7. The time now is 12:58.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.