2-strand rope-to-chain splice

[thinwater]

Anyone know of instructions for this splice? I would like to do a little break-testing and would like to know the best method.

Splicing rope to chain - Ocean Navigator - January/February 2003

It seems there is some though that splicing with just 2 strands is stronger than splicing with 3 (the load distribution is more even), and it would certainly go through the windlass more smoothly. But this does not seem to be something the windlass manufacturers have adopted. Perhaps they are simply slow, or perhaps it is more idiot-prone.

[Stumble]

The two strand splice is stronger and thinner than the three strand, but I have no idea how to make it. Brion Toss discusses it in his book, but doesn't show how to make it.

[pcmm]

I can't see how a 2 strand splice is stronger than a 3 strand splice...you've remove 1/3 of the rope to make the splice!!

anyway a 3-strand to chain splice is pretty compact and goes through a windlass easily.

[estarzinger]

Originally Posted by thinwater

Anyone know of instructions for this splice? I would like to do a little break-testing and would like to know the best method.

Splicing rope to chain - Ocean Navigator - January/February 2003

It seems there is some though that splicing with just 2 strands is stronger than splicing with 3 (the load distribution is more even), and it would certainly go through the windlass more smoothly. But this does not seem to be something the windlass manufacturers have adopted. Perhaps they are simply slow, or perhaps it is more idiot-prone.

There are instructions page 344 of Brion's book - you can get on ipad.

It might be shown on p18 here - I did not look closely enough to be sure that is correct.

It is essentially a modification on the traditional long splice.

It is theoretically stronger (than the 3 stands thru splice) if (and only if) the chain link is small in comparison to the rope size. If the chain link is big and the rope can spread out they are the same. But if the link is small and the 3 strands get forced on top on each other then the 2 strand thru splice can be stronger IF it is well done - but it is not easy to make it really well.

So your results will depend on what chain size you use and how well you make each splice - I tested it and thats what I found - generally I would have said for the average splicer and average chain/rope dimensions there was no difference.

I could find no manufacturer of rope or windless that recommended the 2 strand thru splice, and the easier to make 3 strand thru splice is plenty strong - so I did not follow up on the two strand thru one

[Cheechako]

Originally Posted by pcmm

I can't see how a 2 strand splice is stronger than a 3 strand splice...you've remove 1/3 of the rope to make the splice!!

anyway a 3-strand to chain splice is pretty compact and goes through a windlass easily.

Yeah, I don't get it either. Especially since in the real world chafe at the splice is the more likely failure point I would think.

[Stumble]

Estar,

Which book of Brion's?

What he says about the two strand splice is that because chain has become so much stronger for its size (proof coil and BBB) properly sized three strand simply won't fit thru the links. So the option is to downsize the rope (weaker) or switch to the two strand splice.

His rule is that the rope should be rated to 1.33% the MBL of the chain in question. So 5/16" BBB G30 with a MBL of 7700lbs needs a rhode with a MBL of 10,250lbs. Which means you need 5/8 rope (11,650mbl) which won't fit thru the links.

[thinwater]

Originally Posted by pcmm

I can't see how a 2 strand splice is stronger than a 3 strand splice...you've remove 1/3 of the rope to make the splice!!

anyway a 3-strand to chain splice is pretty compact and goes through a windlass easily.

a. Perhaps you cannot see it, but it remains true.

b. Apparently not.

[thinwater]

Originally Posted by estarzinger

No, this is for a 2-strend eye.
It might be shown on p18 here - I did not look closely enough to be sure that is correct....

I could find no manufacturer of rope or windless that recommended the 2 strand thru splice, and the easier to make 3 strand thru splice is plenty strong - so I did not follow up on the two strand thru one
Why do you suppose this is? That it is more difficult to get right?

My windlass has never liked 3-strand splices. I carry enough chain that it very seldom matters, but I have started some in-line tandem testing that requires very long scope (20:1) and I am coming up a bit short sometimes.

----

(the broader audience, not Starzinger)

And unless you have hard data showing something different, in-line tandems really do require 20:1 scope. The chain has to stay right on the bottom all of the time. I've done a lot of diving and a lot of instrumented testing. Completely different physics than single anchors. But they do have significant promise under certain circumstances.

[thinwater]

Originally Posted by Cheechako

Yeah, I don't get it either. Especially since in the real world chafe at the splice is the more likely failure point I would think.

Actually, the failure is always chafe somewhere else. I have never heard of the splice going, but around a rock or on the bowsprit, yes.

Not something new.

[Jesse]

With the commonly used two strand splice in use for a very long time the third strand goes through the next link then back with the other two into a common three strand splice. It does receive more wear and chafe but can act as a guage as to when to re do the splice. It isn't eliminated.

[estarzinger]

Originally Posted by Stumble

Estar,

Which book of Brion's?

.

It is in riggers apprentice (I checked).

I would guess it is also in one of his series of splicing specific books but have not looked to see (mine are packed away).

I have never asked but would guess no-one recommends it because it is more difficult to do well and has only marginal advantages "in the real world" .

I have asked rope and windless mfg's why they don't recommend the "up the chain"/"shovel" splice and they said it was because it was easy for a link to turn sideways, which will then jam and stall a windless. The point is they had thought about it and had an answer for that splice, so I would guess they have also considered and rejected this one for a reason.

Thin, I am glad you are taking a serious look at tandems. Prior analysis have all been too cursory.

[thinwater]

Originally Posted by estarzinger

It is in riggers apprentice (I checked).

I would guess it is also in one of his series of splicing specific books but have not looked to see (mine are packed away).

I have never asked but would guess no-one recommends it because it is more difficult to do well and has only marginal advantages "in the real world" .

I have asked rope and windless mfg's why they don't recommend the "up the chain"/"shovel" splice and they said it was because it was easy for a link to turn sideways, which will then jam and stall a windless. The point is they had thought about it and had an answer for that splice, so I would guess they have also considered and rejected this one for a reason.

Thin, I am glad you are taking a serious look at tandems. Prior analysis have all been too cursory.

I've tried a shovel splice, and while it is easy to make strong, my windlass really hates that one.

Tandems. I have tried every which way to get the Peter Smith method to work. I have failed over and over, no matter how carefully I place the anchors, which to me makes it too fiddly. I'm not saying it does not hold, just not better than a single anchor, and certainly no better in a shift. Basically, all you need do is look closely at the pictures to see that it actually does not work (the anchors are not set and in several cases are beginning to lift out, if you look closely). I've tried many attachment points, even under the blade and bridles (gotta rule everything out) and nothing helps much. On the other hand, on shale and rocks the math is totally different (no digging) and I understand why some folks find it useful. The mode of action seems to be a matter of tag-team hooking, grabbing, or simply applying friction before the boat can gain sternway. The need for long scope comes from the need to keep the full weight of the primary on the bottom, and if there is ANY hold on the part of the secondary, even a tiny upward angle make the anchor weightless and near zero friction. But it will require a lot more diving and measuring before I'm sure of much.

Anchor testing is a bag of cats. Bottoms vary enough to make anyone nuts. The result is that most anchoring is sort of a black box; we lower away, go though our ritual, and our observations are anecdotal. It either held or not, we don't have a load figure, and we don't know if it hooked on something lucky. Obviously I exaggerate. The result of many hours with a load cell and a lot of diving I've confirmed a few things I thought I knew, and found a few things that weren't quite so. For example, I though Peter's stuff looked somewhat reasonable and rational... until I tried to duplicate the results.