Witchcraft - Splicing Octoplait

[colemj]

And in certain applications, 8-plait has much more stretch than double braid.

Mark

[Seaworthy Lass]

I am about to put an eye splice on our new snubber (16mm nylon octoplait). One end will be attached to a rear bollard. Rather than looping it over and having it permanently take up space on the bollard, I am planning to cow hitch a dyneema loop to the eye splice and throw that over the bollard instead.

I have a query. On the end being attached to chain I usually put a metal thimble (a plastic one deforms quickly). I don't want metal banging on the deck when load is removed from the snubber. It is viable to simply leave out the thimble? With 8mm dyneema going through it will need a sharp 180° bend in the nylon eye splice (less than 1:1).

SWL

[nigel1]

How about keeping the thimble, but frap it, that should keep the metal isolated from the deck.

[JPA Cate]

Nigel, forgive my ignorance, but, I thought "frapping" was wrapping tightly, so I'm not sure what you meant. Did you mean to whip the bottom part of the splice where the thimble separates, with thick enough twine to keep it off the deck? Or, was it something else????

Ann

[StuM]

Ann, I assumed he meant wrapping all around the eye, over the thimble with light line so that you can't see any metal.

[StuM]

SWL, I wouldn't omit the thimble. That will severely weaken the eye.

[Factor]

Interesting stuff, I like the idea of octo as it stows so much better - a few questions, when you say rear bollard, do you mean a bollard at the back of the boat or the rearmost of two bow mounted bollards? Also what size octo and chain are you using and and the attachment method to the chain? I sort of presume you are doing this with an eye to you new boat? What is the displacement?

thanks in advance - always on the lookout for new ideas and skills.

[Seaworthy Lass]

Originally Posted by JPA Cate

Nigel, forgive my ignorance, but, I thought "frapping" was wrapping tightly, so I'm not sure what you meant. Did you mean to whip the bottom part of the splice where the thimble separates, with thick enough twine to keep it off the deck? Or, was it something else????

Ann

I would interpret that as wrapping line around the entire thimble and nylon running around it (with a portion left free at the apex for the dyneema cow hitch).

Great idea Nigel! Thanks.
Something like clove hitches tied in alternating directions to keep the binding straight would work beautifully I think. Maybe like the images below? Pretend that is a thimble holding line .
Or is anything used traditionally?

[Snowpetrel]

I wonder if something like a chain splice would make a very small, tight eye that the soft shackle could be passed through rather than a link of chain.

I would make it around a hollow fid slightly bigger than the soft shackles diameter.

[Seaworthy Lass]

Originally Posted by StuM

SWL, I wouldn't omit the thimble. That will severely weaken the eye.

Dyneema is not good with severe bending (1:1 will weaken a loop by 50%, but with an eye splice this means line strength is retained). Nylon should do better, but I don't have the figures. I was hoping I would get away with it .

Originally Posted by Factor

Interesting stuff, I like the idea of octo as it stows so much better - a few questions, when you say rear bollard, do you mean a bollard at the back of the boat or the rearmost of two bow mounted bollards? Also what size octo and chain are you using and and the attachment method to the chain? I sort of presume you are doing this with an eye to you new boat? What is the displacement?

thanks in advance - always on the lookout for new ideas and skills.

Hi Factor
Plans are only provisional until deck gear is fitted, but I am planning to attach the snubber to the twin bollard at the stern. This means around 14m of snubber will run along the deck. We had this system on our old boat and it worked well. The snubber will be 16mm nylon octoplait. Yacht displacement is around 19 tons.

Previously the snubber deviated slightly around the cabin top at a couple of points with soft shackles. That worked reasonably, but the shackles would sometimes ride along a bit before they jerked back in place. I am playing with trialling the use of low friction rings attached to the cross piece of the bollard using an openable Bullseye strop. This will also raise the snubber slightly off the deck when it is under tension. The strop is short enough that that LF ring can't reach the deck and bang on it when the load is released. If for some reason this doesn't work, I will go back to soft shackles to divert the track around the cabin top.

SWL

[Seaworthy Lass]

Originally Posted by Snowpetrel

I wonder if something like a chain splice would make a very small, tight eye that the soft shackle could be passed through rather than a link of chain.

I would make it around a hollow fid slightly bigger than the soft shackles diameter.

Would it have to be a small eye? I imagine the radius of bend is the critical bit.

[StuM]

Originally Posted by Seaworthy Lass

Something like clove hitches tied in alternating directions to keep the binding straight would work beautifully I think. Maybe like the images below? Pretend that is a thimble holding line .
Or is anything used traditionally?

ABOK #2497 ?

[StuM]

Originally Posted by Seaworthy Lass

Dyneema is not good with severe bending (1:1 will weaken a loop by 50%, but with an eye splice this means line strength is retained). Nylon should do better, but I don't have the figures. I was hoping I would get away with it .

It's not the Dyneema that I was concerned about, especially with a cow hitch. It is the sharp bend in the octoplait eye folding over the dyneema once load is applied that I would worry about.

[Seaworthy Lass]

Originally Posted by StuM

ABOK #2497 ?

That's it! A Single Tatted Bar. Thanks, I have learned a new name .

Originally Posted by StuM

It's not the Dyneema that I was concerned about, especially with a cow hitch. It is the sharp bend in the octoplait eye folding over the dyneema once load is applied that I would worry about.

Yes, I knew you were referring to the nylon. I just meant dyneema loses strength badly with bending, but it still copes with a 1:1 bend, so maybe nylon would handle a bit less than 1:1 (it wouldn't be much less as the dyneema would be hitched on).

[nigel1]

Originally Posted by Seaworthy Lass

I would interpret that as wrapping line around the entire thimble and nylon running around it (with a portion left free at the apex for the dyneema cow hitch).

Great idea Nigel! Thanks.
Something like clove hitches tied in alternating directions to keep the binding straight would work beautifully I think. Maybe like the images below? Pretend that is a thimble holding line .
Or is anything used traditionally?

Yep, that's what I meant.