Splicing high-tech double braid.
 

So I need to put a couple splices in Endura Braid, which has a Dyneema 12-strand core and a more-or-less standard polyester cover. The line is 3/8" diameter, overall.

I have Brion's "Riggers Apprentice", and see the instructions and all about measuring 24 rope diameters for the bury, etc.

So here is my question. For these high-modulus cores, do the instructions refer to the rope diameter of the whole thing, or just the high-modulus part?

So for a 3/8" line (overall diameter), do I need to bury 24 rope diameters of 3/8" (i.e., 9 inches), or 24 diameters of the core, which since it is about 1/4"....6-inches of bury?

-Keith

Keith -
you really should stop by our shop - I'd be happy to run though this splice with you and help out with these other questions too.

Use the new england ropes insturctions for core to core splices for that line.

http://newenglandropes.com/SPL_DoubleCoreToCore.aspx

Hi Keith,
The NE Ropes instructions are good as are those supplied by Samson and Gleistien.
All of them use a variety of techniques (Gleistein offers two), and employ various fid lengths for their measurements. Marlow also has some instructions as does the related English Braids which are all helpful.

I've found Brion's drawings the clearest however for doing the splice. The bury should be 48 diameters for this splice not 24 (as would be appropriate for STA-Set LS etc core and cover splices)
Measure with the cover on for this splice 48 diameters or 18" to be tucked into itself.

If your near Brian's shop I'd stop in as the "learning curve" for splicing the exotics can get a bit costly.
good luck,
jeff

Those numbers work pretty well, but I've run into a couple lines in which the 48 diameters yields an incorrect bury. Lines like NER's Flight Line have an proportionally larger cover than core, which means you'd end up burying too much core.

Instead I usually just mic the core and bury 72 diameters of that.

Thanks for all the input.

Yes, I mis-typed. I looked it up after I posted and realized that the correct length was 48 diameters of the overall diameter.

Brion's instructions look way easier to follow than the ones from New England Ropes.

The one thing that bothered me about all the instructions, Brion's included, was that it seems that once the core is inserted into itself and the core-in-core is covered by the cover again.....that there will be too much slack in the cover.

Specifically, refering to Brion's directions, the core emerges from the cover at the eye of the splice at "core point #1". After putting the core in the cover for the loop/eye, once does not insert the core at this point.....but 8diameters further toward the other end of the line. So it appears that once the splice is all done, the throat of the high-tech core is 8diameters away from the throat of the cover part.
Does that make sense?

Brion's book talks about snapping it against a belay. Is this meant to get the throats and such all lined up? will the core emerge from it self to do this alignment?

For what it's worth, the NER instructions have the same thing, but to my eye, it looks ever worse (even more mis-aligned).

Brian Duff, let me give this a shot on my own, then if I run into a brick wall I may visit. I bought the line a few feet long for this very purpose!

-KM

Kristian is right about the Flight Line, but since the oversized cover is short lived polypro, it's just as effective to strip the cover and lock brummel and go core only, with this configuartion of line.

When inserting the core into itself this entry will be well inside the standing part of the cover, as the splice is drawn up. I've found that a small fid (or large sail needle) is helpful in holding the two marks together as your drawing up the splice. Be sure to massage the slack out of the eye as you're drawing up the splice.
You should have to snap against a belay until the very end with endura braid as its cover has some give.

In addition to Brion's Books (both the Apprentice and the field guide to braided rope splices) take a look at the English Braids website. They present some good photo sequences in their Splicing Directions. Their cordage is a bit more "Marlow Oriented" with the techniques differing somewhat however the principles are still the same. Their core to core splice does employ a cordage with an "intermediate cover" which you don't have to concern yourself with and they cheat a bit by lopping off a bit of the core which makes a little more room in their extra tight tweedy cover.
good luck
jeff

Just wanted to correct my ealier post, you SHOULD NOT have to snap against a belay too much until the very end of running home a covered Edurabraid eye splice. As with a normally constructed core dependent line (with an extra thick covered line like NE Ropes flight line you'd take the 48 diameter measurement only on the core-if your retaining the cover over the eye), the proportion of measurements offered by Brion's method allow adequate slack in the cover until the last inch or so of burying, when a little helpful snapping comes into play.

As I said earlier with endurabraid it (the cover) does have a rounded relatively "forgiving" nature and makes running this splice home pretty easy. V-100 and T-900 are two examples of core dependent lines, from NE Ropes, that require a little more coaxing to get home, as their covers seem to run a little tighter in their weave.
sorry if there was any confusion.
jeff

I think that the core offset you are thinking of is what gives the cover the slack to fit two cores inside the line, Kieth. maybe i misunderstand

!!! there should be no jerking or slamming of anything - not with splicing core to core and the covertail not buried inside the cover.

even then, or really with any splicing of new line commonly used on sailboat rigging, would I say that slamming or jerking is never needed or ever good- I can recall having to slam my way home when splicing- or even setting the line up between two points and dropping my weight on it to move thing along- thats how I was taught to treat line when things weren't going easy. Or I had learned anyway.

Now I have figured out that that is not the right way to splice. Being gentle is much better for the line and your body, and easier on the wrists, elbows and shoulders. Easy on the strands, the helix of the lay, and the splices ability to provide near breaking strength of the line in load. So take it easy - no jerking.

Especially not with core to core and no cover bury- on endura briad, that should be an easy slide.

When applying load to tenson the core and milking the cover down over the constricted core, use your body weight leaning back holding the core in one hand and milking the cover down over it with the other. If things really get stuck - then your trying too hard, try less cover at once, or sit down and 'massage' the line to help work slack into the cover strands from further down the cover . Once the cover is up and over the splice you might have some slack ( if you marked right you will not) and it might be ok to loosen the 'knot' you used to work off of, and milk the excess cover back and forth from the eye down the line and back up to the eye.

Be easy on that line- it would not take much abuse to have many strands bearing no load,due to deformation by rough handling. We see it all the time - bunches of core inside cover, loose cover, incorrect buries. Really funny is when you see those big snags or run showing that the tools use to splice had sharp edges or raised shap edeged lettering- or just that the line was really abused. We call those splices ' Frustrated Lumps'

Splicing is actually really easy to do - have a beer- and enjoy !

Hmmm.

Hadn't thought of that. Guess that makes sense, and since the difference only a few diameters, and there is a ton of extra bury.

I have a firm grasp on standard double braid splices (normal braided dacron), and only later got into locked brummels for single braid.

So this is just an evolution on my skills. Just trying to try it in my mind before I try it for real.

Thanks for all the input. I will be giving this a shot some time soon.

-Keith M