Notes about the Bowline and the Sheetbend knots

Collated Notes on the investigation about bowline and sheetbend knots

Ricardo Nemirovsky

October 27, 2020

The first two images include descriptions for how to knot the bowline and the sheetbend. The following pages include email-exchanges and questions

It all started with an email from Geraldine (October 9):

Dear all ,

I was interested to find that even my son Sam and Pete, both fishermen and handy knotters, hadn’t ever thought of the bowline and sheetbend knots being the same.
The construction and usage is totally different and also the stress and strain is different and depends on which ends you pull..

Thought it might be worth sharing – though it’s not how to tie a bowline exactly. Just my way of bringing looping into the equation.
gx

Although this knot could be called a bowline, a bowline knot is generally is used as a loop and could not easily and quickly be made using the method illustrated here.

 

The knot would be called a sheetbend if the join between orange and green cable didn’t exist. The sheetbend is used to tie two lengths of rope together. Same knot but different pull exerted?

 

Stephanie responded with this email on October 10th:

Hi Geraldine

Thanks. They are incredibly similar, but as far as I can see, not quite the same, though maybe a topologist would disagree. – They probably have the same number of crosses. But the ups and downs are a bit different.

So this is how I was taught to do a sheetbend for net-mending/making, which is just a bit different from a bowline. one thing is that you can easily do the moves correctly, but still get a sheetbend wrong, by pulling at the wrong angle and slipping over the bottom of the loop. Can you do this with a bowline?

                                                                                        Sheetbend right way

 

                                                                                      Sheetbend wrong way      

  
What would be interesting would be to repeat tying them both, and to use them. this would make the nuances of difference clear and show why the practice of knotting, as opposed to drawing knots, is so important.
Just stopped raining
Stephanie

Question:
but still get a sheetbend wrong, by pulling at the wrong angle and slipping over the bottom of the loop. Can you do this with a bowline?

On October 22nd, Geraldine sent another email:
Same identical form but the notation would be different?

Question:
Same identical form but the notation would be different?

Question:
The text includes “The purpose for which a knot is used and the way in which is tied, rather than its appearance, decides its classification”. What does “the way in which is tied” actually refers to?

On October 23rd, Geraldine added:
This already seems to be an ongoing debate, I feel like a collapsed knot, think we need Des. https://youtu.be/ozskWrDM-F4…

Then Stephanie asked Des (October 24th)

Dear Des

I hope you don’t mind me asking this. I have attached the images that Geraldine has sent so you can see them. I have also copied in the rest of the group so they can all read your response if that is okay?

As said, the group has been working on knots, among other things, and one question we have been discussing is about the difference between a bowline and a sheetbend. One of the group, Geraldine, is pretty sure, and she has the literature which agrees, that if you cut a bowline, you get a sheetbend. I’m not convinced, but am open to persuasion, it seems to me that visually they are not quite the same, and that you would get a twisted sheetbend which would be aproblem if netting. There can be no other better person than you to help us resolve this, and we would all be very interested in your view on this question.

Hope you are all well, and things are going well with you. … And thanks loads for your thoughts on this matter.

all the very best Stephanie

Des responded (October 26th):
There are two slightly differing things involved. The structure of the knot & the way in which it is tied. It is certain that the structure of the Sheet Bend & knot that forms the Loop we call the Bowline is the same. Off course the way in which they are tied differs indeed there is the so called weavers knot which is a sheet bend but tied in a particular manner. I suppose that there could also be taken into account which of two of the 4 ends of the structure take the strain .

The most amazing thing to me is that this sheet bend structure is probably the old knot found, 9000 years old found in a early Mesolithic fragment of fishing net found Antrea on the Karelian isthmus in 1913 formally east Finland .( E Albrectsen , Et Offerfund fra Sludegaards Mose ( Fynske Minder 1954. ) Quoted in TURNER.JC & GRIEND P van de, editors. The History and Science of Knots World Scientific Publishing Co Pte Ltd, Singapore, 1996..

It is a wonder that the same knot is still used for the same purpose today.

There is more on the Sheet Bend & Bowline in Knots & Rope Problems by Pieter vab de
Griend the Author 1992 Arhus isbn 87 98 3985-4-7 Chapter 3 People knowing the Sheet Bend structure know the Bowline .

Stephanie you also mention a “twisted sheet bend” not being good for nets there is a way of making the sheet bend in nets that deliberately adds the twist I was told that it was outlawed as it allowed the net to pass the size test but fish small. I have also seen it on billiard table nets. My memory is hazy but I think that it has been referred to as the Bridport knot. Another of its attributes was that it enable a very small mesh to be made, where passing the netting needle would be difficult.

Hope that this is of interest. DES

Des Pawson MBE
Footrope Knots
Museum of Knots & Sailor’s Ropework

Geraldine followed up (October 26th)

following Des’s wonderful email- here’s a video which helped me understand the anomaly
and which shows how they NOT the same knot and that your life could depend on knowing the difference…..

He uses the best phrase i’ve heard to describe the difference in these identical knots – ‘ the lines of force are completely different ‘.

Question:
What is a “twisted sheet bend”?

Question,
How to think about “lines of force”?