Destructive test of rope-chain splice?

[Ric]

I've googled but not found any investigation into a destructive test of rope-chain splice - ie a backsplice v inline splice.

My money would be on the inline splice - but would like to see my intuition checked. And how many chain-links should be covered for optimal inline splice?

Last time I was pondering this was with sustained 50 knots gusting to 65 and with all my 50m of chain out plus another 30m of rode and only maybe 8 links covered by my inline splice. It held - but next time would prefer not to think about it!

 

[Plum]

I've googled but not found any investigation into a destructive test of rope-chain splice - ie a backsplice v inline splice.

My money would be on the inline splice - but would like to see my intuition checked. And how many chain-links should be covered for optimal inline splice?

Last time I was pondering this was with sustained 50 knots gusting to 65 and with all my 50m of chain out plus another 30m of rode and only maybe 8 links covered by my inline splice. It held - but next time would prefer not to think about it!

I've not found any either. Suspect there is not much difference in strength but which you choose may depend on which best passes over your gypsy if using one. Given your actual experience, if I were you, I would continue using the inline splice that works for you but increased to 12 links to reduce your worry about safety factor

Www.solocoastalsailing.co.uk

 

[gregcope]

I think you might need to mention size of boat (tonnage/type) rope and chain size.

However I would assume a good splice retains around 80% approx of line strength. A good figure of eight knot will keep around 60%. Other knots allot less. For example climbers only really use figure of eights; never a bowline.

But ground tackle strength might have more to do with anchor type, setting and swivel type rather than splice. Ie I hear of more issues of anchors dragging or swivels failing rather than a splice failing. You might have different data.

 

[Hadenough]

I put an inline splice, 20mm anchor plait to 10mm chain and worried about it. (I am not the most skilled splicer in the world) . Had the thought one day to put the joint to test by putting the chain / rope joint in the the middle of a spring and motoring against it on the pontoon. Did that WOT for 20mins and all the happened was that the splice tightened up. Held perfectly so I was well happy.

 

[geem]

We have 10mm chain with an inline splice to 24mm anchor-plait. It was a bitch to splice and I only did four links. I really struggled to get the large rope through the links. I have no worry about the strength. We are a 19t boat. I end to ended my chain a couple of years ago and had to remake the splice. It was so tight I just cut it off and started again. It was going nowhere

 

[thinwater]

https://www.ussailing.org/wp-content/uploads/2018/03/1994_Rope_to_Chain_Splice_Test.pdf
http://www.oceannavigator.com/January-February-2003/Splicing-rope-to-chain/

I know that Brian Toss tested elongated splices and that they were very slightly weaker than backsplices.

But the bottom line is that neither fail. Never heard of any of these failing... though I have know of thimbles wearing through, followed by rope failure (I replaced two like that in an industrial setting two days ago--the 316 SS thimbles cracked--seawater was likely a factor). Ropes fail from chafe.

I find it interesting that the back splice is less popular in the UK and the elongated splice is considered obsolete practice in the US. No body in the US would be interested in testing it.

 

[Yngmar]

And how many chain-links should be covered for optimal inline splice?

As many as you would like to saw off every year when the spliced chain links have turned to rust.

Last time I was pondering this was with sustained 50 knots gusting to 65 and with all my 50m of chain out plus another 30m of rode and only maybe 8 links covered by my inline splice. It held - but next time would prefer not to think about it!

Why not just use a shackle? While I do rather let the windlass pull our 25kg anchor out of the mud and lift the combined weight of chain, anchor and scoop of mud up to the boat, picking up a bit of rope while gently motoring forwards is comparatively little effort, so there is no real reason for the whole mess to pass through a gypsy, is there? Therefore a splice is wholly unnecessary - I expect you're only occasionally anchoring with all your chain out and don't usually need to extend it.

 

[thinwater]

Re. Shackles, many windlasses, and all vertical windlasses, will NOT pass a shackle or thimble, making that a non-starter.

Many vertical windlasses will not a pass an elongated splice, which is the reason that most recommend a backsplice. IF that is what they recommend... go with that!

And don't forget that it needs to be redone when it shows wear. That can be 1-3 years, depending on use. And as Yngmar pointed out, any chain splice holds salt against the chain, so those link will need to be cut away each time. But since this will only happen a few times during the life of the chain, the effect on length is totally unimportant.