Author Topic: Important Double Sheet Bend query  (Read 19230 times)

Seaworthy

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Important Double Sheet Bend query
« on: June 17, 2014, 01:19:53 PM »
Hi
I have been a full time cruising sailor for the past six years, during which time I have developed a keen interest in knots.

I have several questions that I am hoping forum members here may be able to help me with.

My first question is regarding the humble Double Sheet Bend, a very useful knot for sailors, particularly when you need to quickly connect two non slippery lines of different diameter reasonably securely on board a boat (typically double braided polyester). I have posted my query on Cruisers Forum with some very helpful members chiming in and providing ABOK links and knot numbers, but no conclusive answers.

I am querying how this simple knot is best tied. I think it is possible that the current method that seems to be commonly taught is not the best one.

All diagrams I have come across show ABOK #1434 and give the description of tucking the tail under the first loop over (ie tying a single sheet bend first) before proceeding to loop the tail around the bight a second time and tucking it under again. See Grogs Animated knots if my explanation is not clear.

When tying any knot, I try and snug it down so it sets neatly and slippage is avoided. For years I have given the first turn of the standard Double Sheet Bend (ABOK #1434) a bit of a push to do this. I have assumed that when the knot is under load it would often slip into this position naturally anyway (wrong assumption by the way). If it did not, I think the knot would not grip as well.
What I end up with is ABOK #488.

Ashley called both of these a Double Sheet Bend.

At some point I started tying the DSB differently so that this push was not needed to get from #1434 to #488. I do not tie a single sheet bend first, instead I make the second turn away from the apex of the bight before bringing the tail under both turns.

The lines I used in the following photos were ordinary double braid polyester: 10 mm for the thinner and 16 mm for the thicker (our yankee sheet). They were older, slightly stiffer, salt impregnated lines, typically what sailors tie knots in. This may have affected results.

This is ABOK #1434, which is the current way taught of tying a Double Sheet Bend:

Seaworthy

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Re: Important Double Sheet Bend query
« Reply #1 on: June 17, 2014, 01:21:08 PM »
This is ABOK #488, the DSB version I tie:

Seaworthy

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Re: Important Double Sheet Bend query
« Reply #2 on: June 17, 2014, 01:22:43 PM »
I could only perform a highly unscientific trial (unknown variable force with few tests, please don't crucify me for my rough and ready methods) tightening up the knot by tying one end on a cleat and winching the other end, but my longstanding impressions about the 2 versions look to be possibly correct.

#1434 seems much worse, as in my trials there was always considerable slippage of both lines. I was hesitant to apply any more force to see if the slippage eventually stopped.

It was suggested on Cruisers Forum that the slippage was occurring as I had not tightened the knot before putting load on it. The problem was that with older salty stiffer line, the knot instantly loosened as I let go and a tight fit was not achievable.

This was the typical result for ABOK #1434:
« Last Edit: June 17, 2014, 01:28:40 PM by Seaworthy »

Seaworthy

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Re: Important Double Sheet Bend query
« Reply #3 on: June 17, 2014, 01:24:06 PM »
For ABOK #488, the version I use, there was always no slippage of the thicker line and only tightening, not slippage of the thinner one:
« Last Edit: June 17, 2014, 01:29:32 PM by Seaworthy »

Seaworthy

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Re: Important Double Sheet Bend query
« Reply #4 on: June 17, 2014, 01:25:04 PM »
Correct me if I am wrong, but to me it seems that a DSB is essentially just a double overhand around the bend. I would call ABOK #1434 a DSB where the double overhand that has been left completely "unsnugged" even if it is tightened up. ABOK #488 is a DSB with the knot correctly snugged.

All other double overhands I have ever come across (whether used on their own as in a stopper, or as part of other knots like the double fishermans) are ALWAYS snugged by rolling over the loops so that that nice ball forms. It was just instinctive to do this whenever I have tied my version of the DSB, as un-snugged knots have the disastrous potential of slipping. ABOK #1434 just never seemed finished to me.

However, the two knots are not the same in use. ABOK #1434 does not turn into ABOK #488 when load is put on it (at least it certainly didn't do so for my winch trials using the line specified earlier).

So my queries are:
- Is ABOK #488 actually better than ABOK #1434, as I have always thought?
- If so, why is ABOK #1434 taught as the correct way to tie a Double Sheet Bend?
- Just out of curiosity, when was ABOK #1434 adopted? Has it always been the knot of use for a DSB?

Also to confirm which version of the DSB is better (for lines of both equal and unequal diameters), is anyone able to do some stress load test for me please?

Luca

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Re: Important Double Sheet Bend query
« Reply #5 on: June 17, 2014, 08:30:39 PM »
Hello Seaworthy,

I am not able to answer your questions, but if you prefer to use the Double Sheet bend dressed as # 488, maybe you can try this "Tresse" version of the Sheet bend(with or without the final slipping):

http://igkt.net/sm/index.php?topic=4880.msg31884#msg31884

                                                                                                                    Bye!

Dan_Lehman

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Re: Important Double Sheet Bend query
« Reply #6 on: June 18, 2014, 04:26:52 AM »
For ABOK #488, the version I use, there was always no slippage of the thicker line and only tightening, not slippage of the thinner one:

Discard them both!
Try this similar knot, intead:
looking at #488, follow the path of the
thinner (hitching) line from the tail
through the knot --it reaches across the
bight (not through it),
turns around it fully,
then turns around again but is tucked through
the bight.
So, with this vision, tie $488 in reverse
(tails are SParts & vice versa --which keeps the
"same side" relationship (tail & tail, SPart & SPart)).
BUT on both turns around the bight, tuck the
working end (of thinner line, in your example)
through the bight (otherwise, you'll have a jamming
knot!).  You might even make another turn,
and the tail can be further tucked out through
its own initial turn around the bight.
(If the diameters are much different, this becomes
problematic to secure, as the large-roped bight will
see too much space for the small hitching line to
be nipped.)

Consider this an extension of the Lapp bend
which itself is the (same-side) SB reversed.

TO LOOSEN & UNTIE, one pulls the legs of the bight
apart, to draw in enough --not much, but enough--
hitching-line SPart to enable one to work loose the
whole thing.  As the thinner ("hitching") SPart is
held by its own turns pressing down upon it but it
is otherwise following a straight path, it should
be possible to forcibly pull it, as described above.
(Big ropes enduring big forces might require some
Big Help --some device.)

The benefit of this multiple Lapp bend is that it can
be made secure-when-slack, and has this forcible
loosening method.

Btw, one can find netting that uses either of these
sheet bend geometries, but the #488 one might
be the more common, and better working.


--dl*
====

xarax

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Re: Important Double Sheet Bend query
« Reply #7 on: June 18, 2014, 04:39:37 AM »
   I had patiently waited till dL pops out, because he is the one that should be advised on this matter : the TWO Sheet bends, and how they are related to the Lapp bend.
   Even without a f... picture, his previous post is very well written and informative - search for the "Lapp" word in the Forum, to find more comments on the same issue.
   For other asymmetric bends, see at :
   http://igkt.net/sm/index.php?topic=4116
   http://igkt.net/sm/index.php?topic=4692.0
   http://igkt.net/sm/index.php?topic=4890
« Last Edit: June 18, 2014, 04:40:17 AM by xarax »
This is not a knot.

Seaworthy

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Re: Important Double Sheet Bend query
« Reply #8 on: June 18, 2014, 05:54:37 AM »
For ABOK #488, the version I use, there was always no slippage of the thicker line and only tightening, not slippage of the thinner one:

Discard them both!
Try this similar knot, intead:
looking at #488, follow the path of the
thinner (hitching) line from the tail
through the knot --it reaches across the
bight (not through it),
turns around it fully,
then turns around again but is tucked through
the bight.
So, with this vision, tie $488 in reverse
(tails are SParts & vice versa --which keeps the
"same side" relationship (tail & tail, SPart & SPart)).
BUT on both turns around the bight, tuck the
working end (of thinner line, in your example)
through the bight (otherwise, you'll have a jamming
knot!).  You might even make another turn,
and the tail can be further tucked out through
its own initial turn around the bight.
(If the diameters are much different, this becomes
problematic to secure, as the large-roped bight will
see too much space for the small hitching line to
be nipped.)

Consider this an extension of the Lapp bend
which itself is the (same-side) SB reversed.

TO LOOSEN & UNTIE, one pulls the legs of the bight
apart, to draw in enough --not much, but enough--
hitching-line SPart to enable one to work loose the
whole thing.  As the thinner ("hitching") SPart is
held by its own turns pressing down upon it but it
is otherwise following a straight path, it should
be possible to forcibly pull it, as described above.
(Big ropes enduring big forces might require some
Big Help --some device.)

The benefit of this multiple Lapp bend is that it can
be made secure-when-slack, and has this forcible
loosening method.

Btw, one can find netting that uses either of these
sheet bend geometries, but the #488 one might
be the more common, and better working.


--dl*
====

Hi Dan
I find the way Ashley has drawn #488 about the most confusing knot I have ever seen LOL. I would say it wins the prize of "if I had to find the most intricate complicated way to show how 488 is tied, this is what I would do". Did he have a sadist streak?  :D

I will work through your explanation of the lapp bend later today, as it is not instantly apparent what you mean. Do you have a link to an image of it? I have searched for "lapp" here, but can't find an image. Don't worry if not, I will work it out (firstly I need to go and test the EStar and Bull Clove after breakfast).

I have been searching for a better knot than the double sheet bend for when lines are of different diameter, so the lapp may be very useful. Has anyone done load tests on it? And if so same diameter line or different? And what diameters? And what line?
All important for where the knot is of most use to sailors.

I generally tie an Alpine Butterfly Bend if I need to join two ropes of roughly the same size. In the last few days I have practiced the Zeppelin until I am super comfortable with it and will make that the knot of choice now. I was looking at the differences between the Alpine BB and Zeppelin yesterday and got all excited when I came up with the Hunter, until I discovered it was already a known knot :). It sounds like it would be a better option if there was no need for the lines to be untied afterwards.

But back to my original question now.

Sailors seem to be taught everywhere to tie the double sheet bend as per #1434, not #488. This may have gone on for decades, I have no access to books to see.

I believe #1434 is inherently weaker than #488, possibly particularly if the line diameters are different and the rope salty and a bit stiff.
Does anyone know if this is correct?
Has anyone done any load tests comparing 1434 and 488?

If 488 is better, then why has 1434 been adopted? :confused:


Dan_Lehman

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Re: Important Double Sheet Bend query
« Reply #9 on: June 18, 2014, 07:06:42 AM »
Hi Dan
I find the way Ashley has drawn #488 ...
WHOA, when I wrote "look at #488" I meant
for you to look at YOUR OWN PHOTO OF IT,
not Ashley's confused scribble (which might
be more accurate --a bit-- to what things look
like when fiddling the small material about which
he wrote, there --yarns).  (Ever notice how anglers
knots are seldom clearly shown --you see careful
tying steps, then instruction to "pull on tag end
while humming Jolly Roger" and ... the tied image
is just a squiggle : I really believe that most of the
illustrators/authors have no clue about what should
result!)

No, look at YOUR image/photo.  It should be clear.
What is tail/SPart/turn/tuck.  There is only so much
to work with; reversal is straightforward.

Quote
Has anyone done load tests on [Lapp bend]?
And if so same diameter line or different?
And what diameters? And what line?
All important for where the knot is of most use to sailors.
THINK about this : substitute "sheet" for "Lapp"!!
After centuries of use, has anyone reported testing
as you ask for this venerable knot,
noting sizes and which side --they're different-- breaks???!
(I know of none, including even myself, say, using
cheaply got mason-/fish-line.  .:.  lazy me!)

Quote
I generally tie an Alpine Butterfly Bend
if I need to join two ropes of roughly the same size.
In the last few days I have practiced the Zeppelin
until I am super comfortable with it and will make that
the knot of choice now.
And you'd use these *fashionable* knots instead
of Ashley's bend #1452 (or 1425!) because ... fad?

Quote
I was looking at the differences between the Alpine BB and Zeppelin yesterday and got all excited when I came up with the Hunter, until I discovered it was already a known knot :). It sounds like it would be a better option if there was no need for the lines to be untied afterwards.

SmitHunter's bend with the tails crossing
a bit differently makes a fine end-2-end knot,
too; and in many cases, even without.

Quote
Sailors seem to be taught everywhere to tie the double sheet bend as per #1434, not #488. This may have gone on for decades, I have no access to books to see.

I believe #1434 is inherently weaker than #488,
possibly particularly if the line diameters are different and the rope salty and a bit stiff.
Does anyone know if this is correct?
Has anyone done any load tests comparing 1434 and 488?

If 488 is better, then why has 1434 been adopted? :confused:
"better" : if it ain't broke, don't fix it.
"There are a hunnerd ways to tie that, and any
one is good as another" (paraphrase of one knotty
utterance by a waterman I recall reading).

Of what I see in commercial-fishing knotting,
most knots have their tails secured : hog rings,
tape, or tucked-through-lay.  I think that one can
see on Deadliest Catch imagery of the Alaskan crabbing
boats the pot warps tied to pot bridle eyes with triple
sheet bends
, in the tail-tucked-repeatedly form,
not one tuck under repeated wraps.

One further idea, re the sheet bend:
instead of tucking repeatedly, as you question,
make those not tuck but "overwraps" --i.e.,
take the end around OVER the SPart,
and only tuck the last one/two passes
(YMMV on needs per material & diameters).
.:.  The overwraps will bind the hitchin SPart
(like in an angler's blood knot / grapevine / snell),
but the final tucks should enable loosening,
by hand.  One might want to make one tuck
as normal, and the final sort of reversed,
by going OVER and tucking back-under,
to put X's "ugly" hard bend, which can defeat
loosening-back-into-knot movement, even if
the hitching SPart can feed back though the
thicker bight a bit.


--dl*
====

Dan_Lehman

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Re: Important Double Sheet Bend query
« Reply #10 on: June 18, 2014, 07:09:31 AM »
   I had patiently waited till dL pops out, because ...
Even without a f... picture,
Oh, but I DO have one --borrowed, and in
the post referred to, not repeated!   ::)

 ;)

Seaworthy

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Re: Important Double Sheet Bend query
« Reply #11 on: June 18, 2014, 08:03:53 AM »
Hi Dan
I find the way Ashley has drawn #488 ...
WHOA, when I wrote "look at #488" I meant
for you to look at YOUR OWN PHOTO OF IT,
not Ashley's confused scribble....

Phew, I would have needed a few stiff Scotches before working on Ashley's diagram of a 488 :D.
I will work on my own photo.

THINK about this : substitute "sheet" for "Lapp"!!
After centuries of use, has anyone reported testing
as you ask for this venerable knot,
noting sizes and which side --they're different-- breaks???!
(I know of none, including even myself, say, using
cheaply got mason-/fish-line.  .:.  lazy me!)

Well, I am not aware of load tests, but how these knots function best has certainly been passed down through the years. How much is anecdotal I don't know, but the old salts from years gone by were a canny lot and would have worked out pretty quickly what worked and what didn't.

For example, if the lines are of a significantly different diameter, sailors don't use a single sheet bend.

If lines are of a thick diameter, neither the sheet bend or double sheet bend are preferred, instead a Carrick is used.

With the new slippery lines, sailors are now at a complete loss :). Up to now I have used a triple fishermans. I know now there are better options and it would be great to find the best one.

I generally tie an Alpine Butterfly Bend
if I need to join two ropes of roughly the same size.
In the last few days I have practiced the Zeppelin
until I am super comfortable with it and will make that
the knot of choice now.

And you'd use these *fashionable* knots instead
of Ashley's bend #1452 (or 1425!) because ... fad?

Nope, because I have read that the Ashley and Hunter could not be untied after a load had been applied, so I never bothered even glancing at them. Sailors generally prefer to learn how to tie the minimum number of knots they can get away with :). I have never come across anyone using the Ashley bend on board a boat and simply dismissed it as an option.

Sailors seem to be taught everywhere to tie the double sheet bend as per #1434, not #488. This may have gone on for decades, I have no access to books to see.

I believe #1434 is inherently weaker than #488,
possibly particularly if the line diameters are different and the rope salty and a bit stiff.
Does anyone know if this is correct?
Has anyone done any load tests comparing 1434 and 488?

If 488 is better, then why has 1434 been adopted? :confused:

"better" : if it ain't broke, don't fix it.
"There are a hunnerd ways to tie that, and any
one is good as another" (paraphrase of one knotty
utterance by a waterman I recall reading).

Well, I have just found that it is "broke" LOL. I tested two braided polyester lines on my winch (16 and 10 mm) and 1434 simply slipped appallingly. 488 held with the roughly similar load I applied (showed zero tendency to slip on several pulls).

My concern is that 488 may have been the bend of choice by "salty old sailors" decades ago and that somehow when it came to putting it into textbooks on boating knots, someone got it wrong and this error has carried on for years (maybe because Ashley drew 1434 as a double sheet bend, putting 488 under weaver's knots instead).

There are not many "old salts" left. They don't look at text books and frankly don't care. They are probably teaching the knot correctly in practice, but most people are now learning from textbooks, classes or the internet and are therefore learning to tie the DSB the weaker way.

I have posed the question about this simple knot on a huge cruising forum (100,000 + members) and members seem extremely hesitant to admit what version of the DSB they are tying, or if they are tying it at all (one person had the courage to respond!!!!). I suspect they don't want to look foolish admitting they are tying knot a way that turns out to be the way that is prone to slipping :).

In lists members have put together of what they consider "vital" the DSB almost never makes an appearance now. I suspect these people would probably end up tying two bowlines when they need to tie lines of different diameter together.

Those using 1434 may find that at a time it is critical it will fail, with disastrous results.

So, my question remains.
Is 1434 or 488 going to perform better under load, particularly when the diameter of the lines is different?
If so, 1434 should be banished from sailors' repertoires :).
« Last Edit: June 18, 2014, 08:06:44 AM by Seaworthy »

asemery

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Re: Important Double Sheet Bend query
« Reply #12 on: June 18, 2014, 02:37:33 PM »
When I make nets using nylon or other slippery twine I tie a double sheet bend thusly:



I have not tried this knot using heavier material.  Tony

Seaworthy

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Re: Important Double Sheet Bend query
« Reply #13 on: June 18, 2014, 03:53:38 PM »
Now I would like to pose an important question to the International Guild of Knot Tyers :).

I have just looked at your home page and checked out the Sea Cadet knots. Low and behold what do I find, you are displaying ABOK #1434 as the method of tying a Double Sheet Bend. I had to smile.

I have attached the photo from your web page below.

Why have you selected this knot in preference to the ABOK #488 version of the Double Sheet Bend?

I have not found #1434 to be nearly as secure using line of different diameter (eg 16 mm yankee sheet and 10 mm line both in double braid).
The DSB's prime purpose is to be used when lines are of different diameters.

« Last Edit: June 18, 2014, 03:55:39 PM by Seaworthy »

roo

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Re: Important Double Sheet Bend query
« Reply #14 on: June 18, 2014, 04:24:51 PM »
Seaworthy,

If you're looking for a more secure bend, it's probably time to look toward a different bend rather than a different dressing of the double sheet bend.  If, for the sake of argument, your favored dressing is more secure, it's still not that great when compared to the continuum of other bends.  In mismatched line, a snag of the larger rope's free end may destroy the bend! And just to make sure the preferred dressing is made and maintained during tightening, you'll need expert and vigilant eyes.

It comes as a surprise to some, but the sheet bend family can become difficult to untie after hard strain.

For all these reasons, I would like to suggest the use of the Zeppelin Bend, which is more secure, stable, determinant in dressing, is more jam resistant, and better handles differences in line diameter:

http://notableknotindex.webs.com/Zeppelin.html
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