Anchor Shackle or Connector

[ctva]

I’m in the process of installing (if that is the right word) a 15kg Rocna to 10mm chain. In all the research I’ve been doing, I’ve got four option;

1 - use a swivel Kong stainless connector that I have currently
2 - a fixed Kong stainless or galvanised connector
3 - a galvanised certified shackle
4 - a stainless Allen key shackle

What do others use and why?
Ithe Allen key shackle good?
Is a bow better than a straight shackle?

Lots of anchor related question I know, but thanks for taking the time.

 

[NormanS]

A lot depends on how much space there is at the bow roller. Do you have room for a bow shackle, which is reckoned to allow better articulation? I have never seen the need for a swivel, and I don't see the need to introduce a stainless item between two galvanised items. I guess that all points to a suitably sized and rated, galvanised bow shackle.

 

[West Coast]

I have used a stainless steel bow shackle, as it was the only one I could find in the chandlery with a decent load rating. Galv anchor and chain, no corrosion issues in the past 4 years.

 

[Neeves]

A lot depends on how much space there is at the bow roller. Do you have room for a bow shackle, which is reckoned to allow better articulation? I have never seen the need for a swivel, and I don't see the need to introduce a stainless item between two galvanised items. I guess that all points to a suitably sized and rated, galvanised bow shackle.

+1

A Crosby G209A gal bow shackle, 3/8" size will have a 2t WLL, higher than anything else available. Each shackle is tested to 2 times WLL better than anything else available. If you follow this route - make sure you buy a G209 A - the G209 is half the strength! They cost Stg10 - cheap as chips! Most stainless shackles are not tested, none will have a 2t WLL and I'd be surprised if any are individually proof tested - except something inordinately expensive.

Available from Tecni in the UK.

Its a no brainer.

One issue - if your bow roller 'sides', or the space between the sides is narrow, you may find a bow shackle catches when you retrieve. You can cut the 'ear' (I wonder if that part has a name?) off the clevis pin and slot the end of the pin (for a flat screw driver) - securing with Loctite or use something less rigorously tested and/or with an alan key slot.

But the fact you have a Kong swivel suggests you have the room to use a bow shackle.

There is nothing wrong with a Kong ( the alternative is an Ultra) swivel. Well engineered. But it is stainless, it will not swivel under water and remove all twists - the only thing it will allow you to do is rotate the anchor with a broom handle should the anchor come up 'upside down' (on which there was a thread recently). If you have space and this is an issue - you can rotate the anchor by hand - a 15kg Rocna is hardly heavy. The better answer, in my view than a swivel is a Bent Link, Boomerang, Flip Link - speak to Geoff at Knox Anchor about a Bent Link (who also sells shackles - though not as good as Crosby's).

http://www.mysailing.com.au/cruising/how-to-boomerang-your-anchor-right-back-at-you

http://sail-delmarva.blogspot.com.au/2017/02/boomerang-your-anchor.html

http://www.tecni-lift.co.uk/Products_3/Crosby-G-209A-Full-Alloy-Steel-Screw-Pin-Shackle

And if you send me an email address I have a video of the Boomerang in use, no - its not on YouTube.

Jonathan

 

[vyv_cox]

You may find this useful http://coxeng.co.uk/anchoring/swivel-problems-and-solutions/

If you don't need a swivel, don't fit one. They are by no means essential. I find them useful and have used the arrangement shown in the link for many years. Stainless between two galvanised components is not a corrosion issue for anchoring equipment, even if you anchor a lot as I do.

 

[prv]

A Crosby G209A gal bow shackle, 3/8" size will have a 2t WLL, higher than anything else available. Each shackle is tested to 2 times WLL better than anything else available.

S3i's stainless "Lifting Shackles" have the same WLL and test load, and crucially they are available in a narrow D shape with a countersunk pin so will fit through my bow roller.

One issue - if your bow roller 'sides', or the space between the sides is narrow, you may find a bow shackle catches when you retrieve. You can cut the 'ear' (I wonder if that part has a name?) off the clevis pin

Any bow shackle except something comically undersized like 3mm or so, will not just "catch" on my bow roller but will simply not fit. Blame the Scandinavians who built my boat and mostly anchor by the stern, but there are plenty of small-to-medium older cruiser-racers with very narrow bow rollers as well.

Also be careful about cutting the lug off the end of the pin - probably OK on your Crosby shackle since it has a flange below it, but if not then cutting off the lug will seriously compromise the strength of the shackle. Here's the result of me trying it as a temporary solution before the S3i countersunk shackle arrived:


The shackle caught on the outer end of the bow roller and instantly opened up. I had to rush to the chandlery that was about to close and buy a Sea Searcher magnet to go fishing for my brand new Spade...

Pete

 

[NormanS]

Some people say there is no corrosion risk having stainless and galvanised in close proximity in salt water.
My own experience is different. I am in the habit of leaving my boat for a month each summer, anchored with a "Bahamian Moor", in various sheltered places in Scotland. Once, several years ago, I attached a "Chum/Angel" using a stainless shackle, at about the 40m mark on my main chain. On retrieval, after a month, the galvanising on three or four links adjacent to the stainless shackle, had completely gone.

Now I don't know if it was something to do with that particular shackle, or something to do with the acidity or otherwise of the mud that it was in, but I have had to live with the result.

I can see no benefit in using a stainless shackle, where a galvanised shackle will do the same job perfectly well, without any risk of damage to the adjacent galvanising. Why take the unnecessary risk?

 

[Neeves]

Pete,

S3i - any links - its not a product that I recognise (but would like to know) - but then I'm in the nether regions. The best shackles gal/alloy are G80 (Crosby G209A - I think they come as 'D' shackles as well) and the best stainless I know are 'just' G50 Cromox - so if there is something better I'd like to know.

Agree - if the shackle does not have a flange the clevis may/will pull through. I tested a recessed head stainless bow shackle - the whole head pulled through (nothing broke - it just deformed and did not meet its min specification (and was bought from Tenci)

Jonathan

 

[LoneHort]

I ditched my Kong type swivel after I saw some strain on the ends. now the happy owner of one of these https://www.mantusmarine.com/mantus-swivel/ which is bullet proof. You may need to widen your bow roller a little bit to get it to fit.

 

[Neeves]

Corrosion of galvanising.

I practice what I preach and I use Crosby G209A shackles. Historically they were attached to a 800MPa steel shank and a G30 (call it mild steel) chain. The links at the shackle and one or 2 adjoining showed signs of accelerated corrosion. I have never taken much notice of how quickly this happened, 1, 2 or 3 years. It was never an issue, bolt croppers, chop them off - re-attach. 3 links in a 50m - its nothing - I really took little notice.

I have always assumed this was 'normal' and a function of galvanic corrosion between two different metals (the shank and shackle are a high tensile alloy and the chain mild steel).

I now have a HT steel chain and HT steel shackle (and an alloy shank, 7075 alloy (a high tensile aluminium alloy). The chain has only been in use for 2.5 years and I have no signs of preferential corrosion of the link(s) at the shackle. I don't have any signs of corrosion of the aluminium of the anchor either. and I've been using it for about 5 years now.


The galvanised coating of chain (or anything galvanised) will erode preferentially in some muds. There are organisms that can live in mud in the absence of oxygen. They produce sulphur contained products which react and form acid compounds, sulphuric acid comes to mind. Sulphuric acid will dissolve galvanised coatings. It is a common issue, particularly in slow moving rives and old harbour facilities (without much fresh water flushing).

The first signs of this are that the galvanising goes black.

This is a reason to wash your chain of mud - and not let the mud fester in your anchor locker.

It does not matter how good the galvanising is - chemistry does not distinguish between good and bad galvanising.

Why Norman's stainless fitting might make this worse - I don't know - but its a major issue with galvanised products (sewage treatment plants being a, maybe, extreme. example).

Given how cheap (is Stg10 too much for a 3/8th" shackle) a decent gal alloy shackle is - I'm like Norman - I simply see no need to use stainless. The stainless i have tested deform like undercooked spaghetti (and a 4t tension, marginally less than the breaking strength of my chain) will not even commence deformation of my shackle - which I have also tested). I wanted to test Cromox shackles, 10mm G50, - but they were so expensive I would not buy them and could not imagine many others would buy them either

Cromox shackles - these are the best I know 9mm or 11mm, WLL is much less than a 3/8th" Crosby shackle, but I did not find their safety factor nor how they are proof tested. But I was discouraged by price, here in Australia - hopefully they are cheaper in Europe. But as they are so much weaker - I was not strongly motivated

http://www.ketten-waelder.com/products/cromox/cromox-lifting/d-shackles-csa/

Jonathan

 

[Neeves]

The Mantus swivel is so large it will detract from anchor performance, it will retard anchor penetration. There have been reports, on Cruisers Forum, of the 'mousing wire' that holds the device together corroding.

http://www.cruisersforum.com/forums/f118/mantus-anchor-swivel-break-183784.html

An extraordinarily clever piece of engineering.

Jonathan

 

[Neeves]

I’m in the process of installing (if that is the right word) a 15kg Rocna to 10mm chain. In all the research I’ve been doing, I’ve got four option;

1 - use a swivel Kong stainless connector that I have currently
2 - a fixed Kong stainless or galvanised connector
3 - a galvanised certified shackle
4 - a stainless Allen key shackle

What do others use and why?
Ithe Allen key shackle good?
Is a bow better than a straight shackle?

Lots of anchor related question I know, but thanks for taking the time.

There is an absence of comments to your final query.

A bow shackle will better swivel with the direction of tension. It will act more as part of the chain than as part of the anchor. A 'D' shackle tend to extend the length of the shank of the anchor, so acts more as part of the anchor. This extends the length of the shank and increases, slightly, the lever arm effect of sideways tensions. Its not a really big issue for a Rocna, the shank will not bend but it might reduce its hold marginally.

The general recommendation is to use a bow shackle.

But bow roller assemblies have become smaller and smaller and some will no longer accept, at all, the width of a bow shackle forcing owners to use a 'D shackle. In the extreme even 'D' shackles can be too wide and the lug (protrusion) of the clevis pin can catch on the bow roller. The fall back is a allan keyed clevis pin - but you really need to search to find them (and in my testing (limited) they are only stainless and not strong - Pete, above, may have an answer).

You need to decide yourself what fits and then which compromises you can accept.

Jonathan

 

[vyv_cox]

The reason I use a 17/4 PH stainless steel shackle is because it has a countersunk hex drive pin. A 10 mm standard D shackle will not pass through my bow roller without serious snagging. I replaced the three links of 10 mm chain between shackle and Kong last season after 5 years when rust began to show. I have never anchored for a month but during the season could spend several periods of more than one week anchoring with many 1-2 nights between.

 

[alahol2]

What do others use and why?

I've a narrow bow roller so I've used a maillon rapide for approaching 20 years now.
I use an 8mm version (on 8mm chain) which passes the roller without snagging, has a stated WLL of close to a tonne and has never given me cause for concern.
Just another option worth considering.

https://www.s3i.co.uk/rapide_link_large_mouth.php

 

[NormanS]

I am fortunate in that both my bow rollers are housed in a wide assembly, so that they can accommodate big bow shackles without any problem. I have one between the anchor and the "Bent Link" and another between it and the chain.

I did suggest that the acidity of the mud might be contributing to the rapid removal of the galvanising, but it seemed to be only in the proximity of the stainless shackle. It is very likely that some of the anchorages in question do have acidic mud. A lot of these anchorages are in sea lochs surrounded by peat bogs, and some of them are so tucked away that there isn't a lot of tidal flow.

As Jonathan suggests, I do notice that in some places, the chain does come up quite black coloured. I'm afraid that I can't use his suggestion of washing it with fresh water, but it generally gets well washed with the deck wash (salt) when being heaved in.

 

[GHA]

I've a narrow bow roller so I've used a maillon rapide for approaching 20 years now.
I use an 8mm version (on 8mm chain) which passes the roller without snagging, has a stated WLL of close to a tonne and has never given me cause for concern.
Just another option worth considering.

https://www.s3i.co.uk/rapide_link_large_mouth.php

Worth noting that Maillon rapides are actually CE certed with a stamped WLL (5:1 from memory) that can be relied on, very few stainless rigging accessories have a certed WLL/SWL.

Maillon rapides are used by the thousands in theatre rigging. Everyone pronounces them May-On rapeed.

 

[Neeves]

S3i's stainless "Lifting Shackles" have the same WLL and test load, and crucially they are available in a narrow D shape with a countersunk pin so will fit through my bow roller.



Pete

Maybe I'm looking at the wrong part of the site but the 10mm 'D' alan key lifting shackles have a WLL of 1t, half the WLL of a Crosby G209A. (and cost factorially more)

https://www.s3i.co.uk/174socket.php

Jonathan

 

[Yngmar]

Below is our setup. It's how Kong recommends their swivel is used and it made sense to me. Plenty of space between anchor and windlass for it all and the bow roller is wide enough to easily feed it too. Currently buried deep in Ria Formosa mud and very pleased with it all. No problems, and held in gusts up to 45 knots (that's the worst we've had so far). No corrosion issues between the stainless and galvanized bits and despite its mixed reputation the galvanizing on the Maggi chain is still good too (we bought it direct from Maggi Italy). The Rocna had a tiny spot of rust on one of the roller bar welds, but we've just painted that bit and so far it's okay. Will try to find some zinc paint for it if it comes back.

The Kong swivel elegantly solves the issue of finding a shackle of sufficient strength to match the Aqua 7 (G70) chain while still fitting through a regular size link. We didn't get the oversized end links, so that we can just cut off a link if corrosion should appear there. Pins are secured with Loctite threadlocker (blue, medium strength).

 

[Neeves]

very few stainless rigging accessories have a certed WLL/SWL.

.

In terms of shackles I agree, Witchard, 3Si, Cromox, being the exception (but none of them match the strength of a Grade B shackles, like the Crosby G209A). Harken might, be stamped, but some of their shackles (from memory, that might be wrong) are 2:1 safety factor.

Sadly, with the exception of Witchard - none of these are commonly stocked in UK nor Oz chandlers.

Jonathan

 

[Neeves]

Yngmar - why do you have the Kong swivel - was it to obviate the need for Maggi's oversized end links or have you found you need the swivel mechanism - or a combination of both

Nice set up, looks neat.

Definite thread drift - how are you finding the G70, ignoring issues with galvanising (that you don't have). Did you down size from 10mm to 8mm - and are you pleased with your choice - any advice to others.

To take this to the extreme - if I said you could have 6mm chain with the same WLL (1.4t) but UTS of 5.6t (so a more common 4:1 safety factor) what would you say (ignoring the cost of (another new gypsy)?

jonathan