Rebraiding for Brummel splice in 12-strand dyneema?

[Jdege]

I'm trying to terminate both ends of some Dyneema 12-strand with tubular thimbles, similar to these:



My understanding is that with Dyneema it's preferable to use locking Brummel splices to keep things from unravelling.

My problem is that I've found instructions for two different approaches for doing a Brummel splice in 12-strand, and neither will work for the second end.

The first involves pulling the other end of the line through the splice. This worked fine for the first end of the line, but it won't work for the second because the thimble is too large to fit.

The second only works with one end of the line, but requires creating an inversion then pulling the final loop through the line to undo the inversion. This works fine to create an eye, but won't work with a thimble.

But then I found this video from the Rigging Doctor. He's making a deadeye, rather than splicing in a thimble, but it seems to me that the technique should work.

The idea is to pass the working end through the standing end after the thimble, then unravel it, pass it around the standing end, then rebraiding it before the bury.

It looks to me as if it would work.

Thoughts?

http://www.youtube.com/watch?v=9-4AYV7jKRA

[s/v Jedi]

You don’t need to do a Brummel lock on a splice when you sew the splice. Find Samson instructions. The splice is even stronger without the Brummel lock.

[GordMay]

Originally Posted by s/v Jedi

You don’t need to do a Brummel lock on a splice when you sew the splice. Find Samson instructions. The splice is even stronger without the Brummel lock.

12-Strand Splice ➥ https://www.samsonrope.com/docs/defa...rsn=b2d98cae_2

All Splices ➥ https://www.samsonrope.com/resources/how-to-splice-rope

[s/v Jedi]

For class 2 rope like Dyneema dimensions are different. Here’s the correct PDF: https://www.samsonrope.com/docs/defa...rsn=f00ad20c_2

[jtsailjt]

For my running back stays I used a Brummell splice on the upper end to eliminate any chance of slippage in a location I can’t see easily, but as you say, you can’t do Brummell splices on both ends using thimbles. So on the lower ends I just pulled the Dyneema around the thimble a little more than a foot from the end and then used a fid to make 3 passes through the line just above the thimble before burying the rest. I wanted to see if it would slip before stitching it but I’ve been using them for 2 years with no loosening at all. Probably not as strong as other alternatives but super easy and plenty strong enough since Dyneema in the size I used is so strong.

[Benz]

Don't bother with a brummel--just do a direct bury of 72 diameters, tapering from the half-way point of the bury onward.
Lockstitch the splice so it can't move when unloaded, and you're done.
There's a myth that a brummel will keep the splice tail from wriggling out, but in reality even a brummelled splice needs a whipping at the beginning of the bury to keep it from bulging out. Not all will bulge, but enough that the minute spent whipping is worth the while.
Under no circumstances should you do multiple brummels--you might as well just tie granny knots, wrap then in duct tape, and hope for the best.

[seandepagnier]

it will work to unbraid and rebraid the strands.

[thinwater]

Sampson (the maker of the rope) published proven instructions for a straight bury. It is the primary method in larger sizes. IMO, the Brummel is a fun, quick variation, and the lock stitch is standard practice.

[Jdege]

Originally Posted by seandepagnier

it will work to unbraid and rebraid the strands.

From what I've been able to learn, rebraiding will work. But lock-stitching should also work.

And lock-stitching looks like it will take less time. And given that I have nine of these lines to complete, less time adds up.

[Jdege]

Any ideas on what sort of cordage I should use for lock-stitching?

[seandepagnier]

i just finished splicing continuous loop of 9/16 amsteel by rebraiding on the other side.

you can use whipping twice too. It is not that much faster, and you have to protect the twine

[solana707]

Originally Posted by Jdege

I'm trying to terminate both ends of some Dyneema 12-strand with tubular thimbles, similar to these:



My understanding is that with Dyneema it's preferable to use locking Brummel splices to keep things from unravelling.

My problem is that I've found instructions for two different approaches for doing a Brummel splice in 12-strand, and neither will work for the second end.

The first involves pulling the other end of the line through the splice. This worked fine for the first end of the line, but it won't work for the second because the thimble is too large to fit.

The second only works with one end of the line, but requires creating an inversion then pulling the final loop through the line to undo the inversion. This works fine to create an eye, but won't work with a thimble.

But then I found this video from the Rigging Doctor. He's making a deadeye, rather than splicing in a thimble, but it seems to me that the technique should work.

The idea is to pass the working end through the standing end after the thimble, then unravel it, pass it around the standing end, then rebraiding it before the bury.

It looks to me as if it would work.

Thoughts?

does this look right ?

[thinwater]

Originally Posted by Jdege

Any ideas on what sort of cordage I should use for lock-stitching?

On large lines (barge towing!) they use a strand from the rope.


For any line you are likely to use on a boat, #1 whipping twine (1 mm) is suitable and has been tested extensively. Not too tight, you don't want to distort the weave. There is practically no load on the stitching. #4 (0.4 mm) twine is enough for smaller sizes.

[Jdege]

Originally Posted by solana707

does this look right ?

No, but I don't see how it's relevant to my question.

That sort of distortion isn't possible with the tubular thimbles I'm using.

[Breaking Waves]

Originally Posted by Jdege

rebraiding

It will 'work' but is a high skill job to make high strength. You need to ensure that all the rebraided strands are equally tensioned so they share the load equally. This is hard to do accurately by hand. Even when done perfectly it reduces strength by (around) 10% vs the long straight bury, and it is difficult for a diyer to determine if an example is 30% or 90% by inspection.

A long straight bury splice with lock stitch is the preferred technique. It is strong(er) and requires less skill and will not come undone.