Soft shackle for mooring tackle.

[Gsailor]

I was talking soft shackles at the sailing club and one chap said he used them to secure his mooring chain!

It was not as bad as I first thought.

He used 200mm diameter amsteel to make a shackle and used it to secure the riser to the chain buried in the seabed.

He said it was to stop metal on metal wearing away.

When the shackle would break (presumably) he had a big shackle that was attached but not under tension.

I told him it was novel to me.

What do you think?

 

[thinwater]

Probably not 200 mm diameter Amsteel. Correction?

 

[roaringgirl]

Chafe will kill it eventually, but in terms of strength, why not? I use a 6mm dyneema soft-shackle to join the nylon snubber to the anchor chain. The boat is 12T and I've tested it in 55kt gusts.

 

[Gsailor]

Probably not 200 mm diameter Amsteel. Correction?

Yes, correction, it was 2cm diameter dyneema, that's 20mm (he called it amsteel... is it the same stuff?) He added a bit of anti chafe webbing.

Whole idea was to stop the galvanised chain being used until the dyneema chaffed through. I have asked him to photograph it if he is ever out there sometime.

 

[Neeves]

If he is using chain - he has metal to metal abrasion anyway.

I suspect we don't have enough, nor correct, information

If he us using 200mm dyneema then his chain must be monstrous - and he has no worries.

Jonathan

 

[Gsailor]

If he is using chain - he has metal to metal abrasion anyway.

I suspect we don't have enough, nor correct, information

If he us using 200mm dyneema then his chain must be monstrous - and he has no worries.

Jonathan

Moderation is not allowing my correction to show. It is 20mm dyneema.

 

[Stemar]

Even assuming it's 20mm, it still isn't going to let go in a hurry, with a minimum breaking strain of 33.5 tonnes. I doubt many of our boats' mooring attachments would stand up to half that.
AMSTEEL-BLUE - Samson Rope

 

[Neeves]

20mm dyneema IS very generous and will need a pretty massive chain to allow the soft shackle to be used.

It is not entirely clear to me how the soft shackle is being used but if it is being dragged over a rough seabed, or rough components (a concrete block) - I'd not be complacent. Most soft shackles are used as a replacement for a conventional shackle - often in specific circumstances. Mooring components are subject to rotation and a (commonly agricultural) swivel is incorporated - I wonder how soft shackles perform in such a situation......

A soft shackle used to retain a snubber, is both easily visually checked and is not the ultimate backstop, noting that a big shackles is also being used, but if there needs to be the big shackle - then the owner obviously is cautious and does not, really, trust the use in that application.

Here in Sydney during testing I can remove the galvanising off a chain within a month and our mooring contractors have sussed this out (long before I was testing) - and use ungalvanised chain.

Jonathan