4 strand rope making questions

[Hornet]

I have been making rope on a homemade powered rope walker for a number of years. I have made 3 and 4 strand of a variety of diameters. I usually use cotton or linen thread rather than polyester. I have never had any thread ‘flatten out’

 

[Steef66]

I have been making rope on a homemade powered rope walker for a number of years. I have made 3 and 4 strand of a variety of diameters. I usually use cotton or linen thread rather than polyester. I have never had any thread ‘flatten out’

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Because you use cotton. When I use Poly it got flatten out. You see strands laying deeper then the next to it. Like I mentioned before, I use a core just about 1/3 of the thickness of 1 strand. I don't let it turn with the strands, only when the rope turns. Maybe I make a video how I do it in my topic about rope making. https://shipsofscale.com/sosforums/threads/make-your-rope-on-a-rope-walk.9094/

 

[Ben Gilbert]

I believe that four-stranded rope in hemp was traditionally made with a stationary heart (the traditional term), rove through a hole in the top on the ropewalk. Its primary purpose was to fill the void between the strands so that they would not collapse into the center and the rope would remain round. Four-stranded line was usually considered to be more supple than three-stranded line. As an archaeological example from Vasa, the hearts are usually just a few yarns (7 and 9 the most common), Z-spun and S-twisted into a loose cord that does not appear to be twisted as the rope is closed. I suspect in a model, where the line is under no real load, the heart will not matter, unless one wants to run the raw rope through a process of stretching and running over a pulley to compress it. The longer fibres in synthetic thread, as noted above, probably resist strand collapse perfectly well for a model.

In traditional terminology, a 12-inch rope is 12 inches in circumference, a little less than 4 inches in diameter. This would almost certainly be cable, as it is nearly impossible to make a normal hawser- or shroud-laid rope of this size that will balance. As a result, it would have a left-hand (or S) lay if made from Z-spun yarns.

As a side note, I have spent the last weeks excavating a rowing barge from 1738, and it produced some cablets (probably anchor cable but possibly stays) only about 40 mm in diameter, which would be 4½ or 5 inch cable.

Fred

Dr. Hocker, when you talk about the impossibility of making large hawser laid rope because it will not be balanced, are you referring to the unequal tension exerted upon the interior versus exterior yarns in each strand? I've read that one reason for the development of cable laid rope was to limit the size of the strands and therefore limit the disparity between the tension of the inner and outer yarns in a strand.

 

[Steef66]

There is a essay called:
The Need to Record Ropes and Rigging on Wreck-Sites and Some Techniques for Doing So by Damien Sanders
He mentioned that a rope before 19th century possible is never made thicker then 9" in circumference.

I can't find the reason in the essay, but I believe it has to do with the difference in lenghts of the yarns in the strands when twisted. The outer layer yarns will be longer then the inside yarns. This fact will make thicker hawser rope weak. So after 9" they use cable, that is stronger because the is less difference in lenght between the yarns.

 

[Bob Cleek]

I believe you meant to say, "... rope before 1800..."

 

[Steef66]

Thanks for the correction, English is not my native language.