Step salsa down in size.
 

On my A-Cat I am running a 10:1 internal mainsheet cascade with 9mm salsa in order to provide a good hand by the time it gets to me out on the trapeze. The problem is it's a relatively big line bent around smallish blocks. my plan is to replace the standing portion of the salsa with 1/8 amsteel, but am not sure how to go about it.

My first thought is to end for end the salsa into a 8mm dyneema piece, then that into a 6mm piece, and on down to 3mm, but this seems like a lot of discrete steps. Does anyone have a guide for how large each step down can be?

Taper
 

Hi there,
A cascade has at least two pieces of rope; how is yours configured? Once I know that, we could talk options.
Fair leads,
Brion Toss

Brion,

It's a 2:1 initial running 3mm amsteel that cascades to a 5:1 with 9mm salsa,then falls to a ratchet block to exit the boom, then another ratchet flip flop block to trim from. The issue is the salsa is too large for the blocks and pulls itself into a large rope plug that keeps the line from running cleanly.

If I replace the salsa with 3mm it runs fine, but is far to small to grip by hand, so what I am trying to do is taper the salsa into thin quick running line to keep it from binding. My plan right now is to end for end splice the 9mm into 6mm, then 4mm, then 3mm. It is a little cumbersome and a lot of steps, but other than a machine tapered line I am not sure how else to get it to work.

Option
 

Hi again,
How about inserting the 3mm directly into an adequately-large single braid. Bury it a couple of feet, and stitch a lot, neatly, for a smooth transfer of energy. Whip the end of the single braid at the transition.
One trick here is to position the transition such that it goes through few if any blocks.
Fair leads,
Brion Toss

Unfortunately there is no way to arrange it so that the larger doesn't run through blocks.

I did consider trying to use the Samson Smooth Ice cover installation splice but couldn't get the larger line to bury in the smaller. The size difference was just too large. I could certainly just bury it up the middle, lock stitch it, then whip it to see if it holds, but I am concerned this wouldn't transfer the load appropriately, and would jam in the blocks.

edit:

I received my order of line and documented all the testing I did as well as my final result.

In order to be as efficient as possible I wanted to go from 9mm salsa to 3mm dyneema in as few steps as possible. I think with one of the Toss splicing wands it maybe possible to eliminate a step, but I don't have one so can't test it.

I have no way to test strength, but because the tapers are somewhat shorter than ideal the stress risers created are likely going to cause the line to break. In this application reducing the leingth of the total splice was more important than retaining maximum strength because the total package is far stronger than needed for the expected loads.

1) 9.5mm Salsa was end for end spliced into 6mm dyneema each end was tapered 17" from the crossover
- tapering the Salsa first was required to make this step. Here a wand would have been prefered.
2) Then 6mm dyneema was end for end spliced into 5mm dyneema on a 17" taper.
- I suspect that with a wand the 6mm could be buried into 4mm, but with the Selma finds I couldn't get the line throug
3) 5mm was spliced into 4mm. With each side tapered 14"
4) 4mm spliced to 3mm. With a 11" taper.

So from the Salsa to the 3mm amsteel is a total of four splices, and a distance of a little over 5'.
If I am correct that 6mm could be buried into 4mm directly then it would be 3 splices and not quite 4' long.

What I found is that generally dyneema will open up enough to accept a bury from up to 1.5 times its original size. I need to replace my #4 Selma fid before making the finish rope and posting pictures, and I have no idea where this would have an application other than here, but I have found it a fascinating experiment that will cut weight from my boat and reduce line friction at the same time.

Inserts
 

Hi again,
The wonderful people at New England Ropes tested inserting 5/16" Endura 12 into 5/8" Regatta Braid, and got a break in the latter, at full strength. This was with a 6ft bury, as I recall, making it about 115 diameters. No reported rope distortion. I'm much more inclined to insert small into large, as a result, especially where the differences in size are great.
Fair leads,
Brion

Brion,

So your recommendation would be to just run the 3mm as a core inside the Salsa? It would be a much cleaner installation so I am intrigued, but I'm not sure how it would work.

1) how would you secure the core? Just lock stitch it once, and if so at the bury or further down the line, says where the core terminates?

2) Since I at least cant get 8mm to bury in 3mm how would you smooth the transition from just the core to core/cover?

Splice
 

Hi again,
I do a palm-and-needle whipping, two if I expect the lead one to see much chafe, then milk the rope firmly down the standing part, and make a series of "invisible" stitches, working away from the whipping. Very important not to make either rope bunch up. Most of the buried tail is not stitched to, so the covering rope can stretch out and compress. Sort of like the tail on a Whoopee sling, where you put the bearing at the head of the splice, and let the rope stretch out on the tail.
Fair leads,
Brion Toss

Brion,

So you would just use the whipping to smooth the transition?

The major issue is that the line has to be able to run through a Harken 40 fiddle so the line is already right at the maximum line size, really it's already too big. But it's also the largest block that will fit inside the boom so there isn't much I can do about that except for changing down the line size. An abrupt increase in thickness is going to cause all sorts of issues, particularly if it increases line size beyond maximum block size.

Oh
 

Hi again,
If the tackle cannot be proportioned such that the transition avoids hitting the block regularly, you might try removing half the strands, burying them, and whipping down the rest with fine Spectra twine. If you remove alternating left-and right-laid strands, it will leave you with a coherent 6-strand braid, and you might be able to insert that. Alternatively, you could try whipping the end of that reduced braid to the surface of the core strand -- its diameter will be less, and should enter the block about as smoothly as a buried tail, and provide a ramp for a fairer entry for the full-diameter section behind it. I rather favor this version, and hope you will try it. Even a full-diameter stop has shown great success going into rather small blocks, without chafing or binding.
Fair leads,
Brion

I'll give it a try tonight and see how it goes. Pics to follow.

So I tried just burying the amsteel and whipping it, but it is far too large to fit. After looking at it again the real issue is in the system there is a Ronstan 30mm block that had a max line size of 6mm so there is no way this is going to work, even with tapering. I am going to have to replace the block with something larger.

It isn't shown, but I did a second whipping over the first to lock down the fuzz on the end of the salsa. It isn't even close to fitting inside the 30mm block.

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Rebuilding main sheet

Size
 

Hi again,
Sounds like the Rigger's Curse: Large rope and small blocks to you. 30mm blocks are typically used for a maximum line diameter of 5/16" (8mm), so your Salsa was fat, even before the insertion of the Spectra. One option is bigger blocks, but you might consider a different configuration, like hanging your blocks on a long pendant, anchored at the gooseneck. With this you might be able to proportion your tackle so that the Salsa never enters the blocks. You'd have the same overall elasticity.
Fair leads,
Brion

I went ahead and upgraded the 30mm to a 40mm block which has helped a lot. The biggest question now is how long of a pennant I can leave of the smaller line.

The goal is to always grasp the larger line, but use as much of the 3mm as possible. unfortunately I forgot to measure where the line exits the boom when sheeted in fully, so I am going to have to wait until the boat gets back from the yard to finish this up. I think it's going to be about 12 foot of 3mm With another 12' of 8mm. But it will have to wait.


Brion,

You idea of just burying it is working very well by the way. It looks a little silly since I redid the whipping from these pictures, and stepped the 8mm down over 6 inches, then whipped the entire transition to hold everything in place. It's a little stiff now, but I ink it will soften in time, but even in its current state it travels pretty cleanly.

Sadly the weight savings won't be as high as I was hoping, but still nothing to sneeze at.

Addendum
 

Hello again,
The topic of tapered and/or dissimilar running rigging is a hot one these days, as riggers figure out how to get the most out of the newer synthetics. To some extent we are simply trying to approximate how we used to blend wire and rope, notably for halyards, but there are many more variations available. For instance we can pair either covered or uncovered HM to comfortable single- or double-braid Dacron tails, or end-to-end splice "blended" double-braids to Dacron. As an example of the latter, we are currently splicing 5/16" Classic Endura Braid to 3/8" Vintage Dacron tails, for some reef clewlines. The HM portion makes for a more positive reefed position, with thin, light, tough rope, and the splice stops well aft of the belay, so the crew only handles Dacron. The constant-diameter splice we are using has been shown to achieve about 80% efficiency, relative to the strength of the Dacron portion. Other tapered splices have shown efficiencies at or near 100%. More research is needed -- people trust their lives to these splices, so we must be sure of them -- but the possibilities for stronger, lighter, and even cheaper running rigging are many.
Fair leads,
Brion Toss

I am a bit late on this and may have mentioned this on SA on a similar thread. But if there is a smaller diameter Salsa then use that and bury the Amsteel the entire length of the Salsa to build the diameter back to what you want. This is what I do with my halyard although I am using Tenex instead of Salsa. Tenex of course is polyester but I don't need it for the strength. I am splicing 3/8 Tenex to 3/16 Amsteel. I have several season on it. It was discussed on this forum back when I was first replacing my wire halyard with the Amsteel. I did not replace the sheaves so needed to keep the Amsteel small. I can now report that this has worked fine although I do remove some of the Amsteel each season to get a clean section going over the sheave.

Variation
 

Hi,
We sometimes do a similar thing with running backstays. Most of the length is HM -- covered or uncovered -- and is inserted several feet into a single-braid Dacron tail. We lead this tail through a single deck block, and thence to a cockpit winch, and the bury is far enough that the HM is wrapped around the winch at least 3 times by the time the load comes on. The rest of the tail is empty making things lighter, cheaper, and easier to handle when the runner is slacked on the lee side.
Recent tests have shown that we don't need to worry about having the HM on the winch for security,but with the HM compressed inside things are arguably stronger. Whether or not to bury it that far might depend just on how much room there is in the tailer on the winch.
If the HM is of the covered variety, we strip the cover just below the insertion into the tail, which in turn is positioned so that it remains clear of the deck block.
Fair leads,
Brion Toss