G70 chain/anchor connectors

[Neeves]

More people are talking of G70 chain, some are even proposing buying it and some have made the plunge.

For those that use G70 chain, how do you connect the chain to the anchor? It might be useful if you define your chain and anchors size/type. Have you found any problems with the solution devised. Do the connectors match the chain for strength and have the connectors ever been tested, or supplied with a specification? Did the chain come with a test certificate?

Jonathan

 

[noelex]

I got Maggi to weld on some oversized links to both ends.

This makes the chain a custom order. This is a new connector from Maggi. It looks like a good (but expensive) alternative. with a titanium pin.

Note: I have not used or even seen this in the flesh and you may need to use a shackle as well for some anchors, but a large shackle will fit preserving the strength of the chain.


https://www.jimmygreen.co.uk/item/55699/maggi-oversized-link-for-calibrated-chain

My chain did not come with a test certificate.

 

[Neeves]

Hi Noelex,

Thanks.

The Maggi connector is made by Rud, or was, they have discontinued that design. Maggi must have them galvanised, as Rud do not recommend that procedure. I too note the idea they are titanium pins - I wonder, as they are magnetic and Rud do not mention titanium. They are Rud clevis pins, it says so on the pin. They will not fit an anchor, you must use a shackle - the 'gate' only takes a 8mm or 10mm chain, so no chance of taking a shank (unless its a 4kg anchor!). The Rud links are huge, that's a 8mm, or 10mm or 12mm chain - so that gives you an idea of scale.

Your oversized links - did Maggi galvanise them as part of the whole rode?

You have this decision to make, or you have made it - what are you installing on the new yacht. You are one of the few with long term G70 experience.

Jonathan

 

[[2574]]

I've taken the plunge and gone for grade 70 8mm chain from Maggi, swapped out from 10mm grade 30. The old rode - 40m 10mm + 30m 18mm anchor plait weighed in at 16kgs lighter than the 80m of 8m chain that I have now. So now all chain for a relatively small weight penalty.

The chain has the Maggi connector on one end and I have connected this to a Rocna 20kg anchor using a Petersen stainless shackle which has a WLL about 30% stronger than the WLL of the chain. I have some pictures but can't post at the moment but will later if that would be helpful.

I had to swap out the winch gypsy from 10mm to 8mm which was expensive but then the whole experience has been pretty costly. Anyone want a perfectly serviceable 10mm gypsy for a Lofrans Cayman winch?

I have specification and test certificates for both the G70 and the Petersen shackle. Haven't tried it in anger yet, that to come soon.

 

[Neeves]

Thanks Rob,, It sounds as if you are just a few steps behind us, we have used our new rode but only upto about 35 knots. I had wondered if the Maggi connector might be an issue on bow rollers. Enough people complain about a common bow shackle, or the end of the pin of a common bow shackle, fouling the ends (flanges) of the bow roller. The Maggi link should come 'in' vertically so maybe not an issue.

Ideally this is an exercise done when commissioning a new yacht - then you do not have the issue of buying a very expensive new gypsy - but life isn't that straight forward. We have a spare 8mm Muir Atlantic gypsy, but its an expensive item to post from Oz (but we will be in the UK your summer).

What size of yacht are you?

How have you found the space differences with the new rode? Towering, and knocking the tower over, for us has disappeared.

Images of the shank end, Petersen shackle, Maggi link and chain would be useful. We are using devices similar to but much smaller than the Maggi link (6mm, G80 with G100 pins, Van Beest's Omega link from their Excel range) that I have specially coated, then a Peerless Grade B 3/8th" shackle, twice the WLL of the chain. Ours is a 6mm G80 chain, like you 75m. 38', 7t, cat.

Again thanks - it will be interesting to hear if you find any negative issues - so far we have found none.

Jonathan

 

[noelex]

Your oversized links - did Maggi galvanise them as part of the whole rode?

Yes, I presume they welded the larger links before they galvanised the chain.

You have this decision to make, or you have made it - what are you installing on the new yacht. You are one of the few with long term G70 experience.

Results were mixed with our G7 chain.

I think all the evidence shows that keeping the rode as light as possible, as well as consistent with adequate strength and abrasion resistance, and using an anchor as large as can be reasonably managed, is the best solution for assigning the relative weights of anchor and chain on a cruising boat.

G7 helps achieve this, but there have been some practical problems. Notably, a short chain life of three to four years (note: I anchor almost full time so this is over a 1000 nights at anchor).

Such a short life is inconvenient, as well as expensive. Alternative brands of G7 may perform better (I would hope so), but availability especially with suitable delivery to out of the way places, limits the brand choice. Given the heat treatment used on G7 and smaller wire diameter, I think it is important to replace G7 before there is anything more than very minor material wastage. This further shortens the potential life and increases the chance of using chain that is unsafe.


For the new yacht, I am going back to G4 chain. The chain storage on the new boat is in a locker a long way from the bow which helps, and easy replacement/regalvanisng together with long life win out, although I still think for many boats G7 is a good solution.

 

[Neeves]

Re-galvanising chain is an issue - but of a different source. It was a cheap proposition its now, looking globally, becoming more difficult and more expensive. Every country used to have leisure anchor chain makers, not so any more, they have closed down and import from China. America is a last bastion of domestic sourcing but even there they currently sell imported as well as domestic - how long they keep up the domestic production - it will be interesting to see. But galvanising - lots of environmental controls - and they add cost. The numbers of galvanisers have contracted and the ones willing to process chain more so. Many people I hear from say they simply would not bother to regal any chain, just buy new (and the main reason is, cost. (For example - are then many chain galvanisers in Greece). So the idea of not being able to regalvanise G70 might start not to feature - don't know, we'll have to wait and see.

I might add - 1,000 nights at anchor is 2 lifetimes, or more, for many people and their chain - its a non event. Lightweight chain is much more critical.

There is a chance Thermal Diffusion Galvanising might be repeatable, Its one of the trials I have scheduled in the future. Take some old TDG coated chain and re-coat, again using TDG and re-check strength. The theory says its kinder on strength, another unknown. As you can imagine finding old TDG chain is a bit difficult.

TDG is meant to be a harder coating and G70 and G80 are harder steels so thinning through abrasion should be at a lower rate.

Its all a bit unknown.

Interestingly Dashew, who is the original proponent of G70 (I think) - and I've often wondered what prompted him and how he persuaded Peerless to make for him - makes no mention of the reality of an inability to galvanise. He mentions the advantages but completely ignores the downsides (though I might have missed it - his website is not really set up to easily read about G70).

Dashew also studiously omits mention of the difficulty of finding matching connectors - hence wondering how people solved the problem.

Jonathan

 

[noelex]

Dashew also studiously omits mention of the difficulty of finding matching connectors - hence wondering how people solved the problem.

He advocates getting the G7 chain made up larger end links (as I have done) which removes the connection issue.

http://www.setsail.com/anchor-chain/


Steve Dashew has some great ideas. Almost everything he publishes about cruising boat design makes lots of sense, and the more I cruise the more sense it makes .

He pushes the anchoring boundaries using very thin chain (3/8 or 9.5 mm G7 in his FPB series up to 110 foot). He teams this with large anchors, a 240lb Rocna on his smallest 64 foot boat.
He takes advantage of this powerful anchoring gear cruising ares with difficult anchorages and anchoring at very short scopes when it is needed.

Modern anchoring gear has changed. High performance anchors and lightweight chain are a relatively new option. This has been combined with reliable and powerful windlasses that can lift heavy anchors effortlessly. This opens up a multitude of cruising grounds that were previously not viable. As these are new developments and few have take advantage of the options this sort of approach opens up. Steve Dashew is a real pioneer.


The only problem with his approach to chain is that replacement is a special order. Most spare parts can be shipped these days reasonably easily to out of the way places, but for chain the heavy weight and long delivery time (for a special order) creates some problems. When choosing essential parts such as anchor chain there are advantages in choosing parts which can be sourced anywhere. It is also helpful to choose parts with a long lifespan.

In terms of regalvanising I would not rule this out for G7 chain. There are differing opinions concerning hydrogen embrittlement, but the most common view is there is only a small loss of strength. The bigger issue is that you need to be careful with G7 it is done (or the chain replaced) before there is any corrosion and loss of material. G4 chain is more forgiving.

Regalvanising still seems reasonably readily available, even more so in out of the way places that cruisers tend to frequent.

 

[Neeves]

Noelex,

Are you aware of a single case of HE in G70 chain, I have not found one. Lots of armchair experts - but not a shred of evidence.

One oft repeated commented is that HE is an issue because G70 is brittle - I'm not sure what these people mean by 'brittle' but in America G70 is meant to have a higher elongation to break than G43 and G30. The reality is that G30, in America, is more brittle than G70. In Europe G30 and G40 are indistinguishable, in terms of extension to break, from G70.

It was obviously not an issue for you as you used G70 for 4 years.

Jonathan

 

[noelex]

Noelex,

Are you aware of a single case of HE in G70 chain, I have not found one. Lots of armchair experts - but not a shred of evidence.

Yes, I agree. That is my point.

Hydrogen embrittlement does not seem to be a practical problem when re-galvanising G7 steel.

 

[Neeves]

The problem of regalvanising G70 has nothing to do with HE. 'Raw' American G70 chain is a Q&T product derived from a product very similar to G43, G70 has some boron added but that apart it is virtually, if not actually, identical (to G43). The strength of G70 is imparted by the Q&T process, the heat of galvanising degrades the strength imparted during the Tempering process. Basically American galvanised G70 is not a G70 strength. Maggi G70 is different, it appears to be based on a different feedstock and may originally be a G80, G100 (or something in between) as when it is galvanised the final product is more like a true G70 strength. It might equally be a completely different alloy - but it is also a Q&T product. If a second galvanising were conducted, and then a third and fourth the eventual outcome would be that the strength of the chain, American or Italian, would revert, at some point, to G43 or G40.

There are no hang ups about G43 and HE - so if there were risks those risks would actually diminish with each and subsequent regalvansing.

Initial galvanising of G70 is conducted by people who are well aware of the issues of galvanising Q&T high tensile steels and they both (Peerless and Maggi) state they take HE into account - and there are certainly no recorded case of HE in G70 chain, or none that I have heard of. If another supplier entered the market (seems unlikely its very small), who might not be so conscious of HE - the situation might change. The best documented cases of HE I have found have been of galvanised high tensile bolts - usually bought to a tight budget. So be very cautious of cheap, gal HT bolts from 'offshore'.

But to return to the question - G70 usage is never going to be anything but niche unless connectors are easily available to allow anyone to buy the chain off the shelf and attach it easily, cheaply and safely to an anchor. The situation is worse for metric chain as its link aperture is so small. So if users have found, cheap and successful but novel ways to join chain to anchor - it might engender more interest

Jonathan

 

[MM5AHO]

HE isn't really a major problem in galvanizing. Its the cleaning part of the process where it occurs, immersion for hours in HCl. But there are other ways to clean steel not using acid.
HE isn't a result of immersion of steel in liquid zinc.

 

[Neeves]

Thanks Geoff, another myth dispelled.

Jonathan

 

[[2574]]

Here are some pictures as promised of the G70 chain connected to a Rocna 20kg via a Petersen shackle. The picture also shows the oversize Maggi terminal link. How well this link runs through the roller remains to be seen. As is evident from the photo it assumes a vertical plane so hopefully won't cause a problem but if it does lay over to horizontal then it may well jamb. We'll report on experience if it proves to be a problem.

Here also, in case of interest, is a link to the test certificate for the Maggi chain and Petersen shackle (both PDF format):

https://dl.dropboxusercontent.com/u/64249185/Aqua7-Chain.pdf

https://dl.dropboxusercontent.com/u...h Tensile Stainless Steel D shackle PH2TB.pdf

Rob

 

[noelex]

Thanks for the detailed photos Robih.

The Maggi connector looks like it is a great, if a bit bulky, solution to connecting G7 chain without resorting to welded larger end links. Can you comment on the security the titanium pin? I gather it is a friction fit and is then secured with two grub screws, but this is not clear from the documentation.

 

[Neeves]

There must be two designs of Maggi link. I have 2, an 8mm and a 10mm, they (Jimmy Green) sent the 10mm by mistake. The pins, on mine, are not titanium, as already mentioned - its magnetic and heavy. They are secured as one side of the link has a slot too small for the pin to pass through the other end is secured by a large split pin, cotter pin, that needs be hammered in. The only way to take the enlarged link off would be to drill out the cotter pin and hammer out the clevis pin (as not being titanium, 'feeling' like steel and not being galvanised - I suspect it will corrode solid). The clevis pin is marked 'Rud 10' as is the link itself. The pins are oval is shape.

I am due to test, to destruction, the 8mm version and return the 10mm model.

Robin's oversized link looks different to mine as Robin's clevis pin reaches the end of the hole where as mine stops short to allow space to hammer in the cotter pin.

Jonathan

 

[Neeves]

Connectors like Maggi's are common in the lifting industry, Gunnebo call theirs Bergloks, Van Beest, Omega links (for obvious reasons) the Chinese appear to be calling them Ohm links, again for obvious reasons. Maggi's links from Rud are huge, compared to most others. These links are available widely in a G80 and G100 quality (not sure about G120) No-one appears to sell them galvanised (galvanising, Hot Dipped Galvanising, appearing to be a no no for G80, G100 and G120 components).

They are all made such that they only take the chain link of the size designated, so a 10mm link will only take a 10mm chain - a 8mm chain will fit the slot but not the clevis etc.

The clevis are usually retained by hammering in small slightly compressible pins that lock the clevis pins in from either end. My understanding is that the locking pins do not alter strength, simply stop the pin falling out. It is, again apparently, possible to drill the retaining pins out, change the chain and add new retaining pins - which might seem a lot of hard work - until you are told how much a G100 link can cost (see Jimmy Greens website for prices). The clevis pins and retaining pins are sold as spare parts. These connectors come in both imperial and metric sizes.

I am using Van Beest's Excel Omega links (smaller than the shackles I am using) as my connectors on a G80 chain, with Peerless gal, bow, Grade B shackles.

Robin - why did you go the Petersen 'D' shackle route and not with a gal bow shackle, say Crosby G209- A or even stronger (by 30%) the Peerless shackles?

Jonathan

 

[[2574]]

Robin - why did you go the Petersen 'D' shackle route and not with a gal bow shackle, say Crosby G209- A or even stronger (by 30%) the Peerless shackles?

Jonathan

To b honest I've used the Petersen shackle because I had it in the boat's hardware bag from a previous anchor rode setup. I would prefer a galvanised Crosby type as you suggest but having paid serious money for the Petersen shackle I thought I had better use it. I am conscious of the galvanic corrosion that might arise though so maybe I'll fork out for a galvanised Crosby.

 

[Neeves]

If you dig though a company called Starrr in America, yes 3 rs, who sell lifting 'stuff' you will find they have on their website a Peerless, Peerlink, Grade B, 3/8th", bow, gal shackle for $2.95 each, I assume there will be some postage (and I'm obviously not sure they will sell one shackle, only). Its not much to fork out and annoying seeing that price and knowing how much a less strong shackle here costs - grrrr! Starrr might sell other brands, I did not look.

The Peerlink 3/8th" Grade B, make sure its a Grade B and not the weaker Grade A, has a Min Break Strength of 12t vs 9t for a Crosby G209 - A. Campbell Grade B shackles are as good as the Peerlink, again make sure they are a Grade B, but do not come in the same range of sizes as the Peerlink. The 3/8th" shackles have a 7/16th" clevis which will not fit in a 8mm Maggi G70, nor G40 link (but will fit an Australian 8mm Grade L (G30) link). Peerlink shackles come in 1/16th: increments from 3/16th" but you need to check sizes. The 3/8th" shackles will fit a imperial 5/16th" G30, G70 and G43 chain link.

Do not touch CMP Titans Black Pin shackles they do not meet their own specification, of 10t MBS. The Yellow Pin shackles are fine but have a MBS of only 6t. Crosby, Campbell and Peerless all meet specifications. Columbos McKinnon also make shackles but I have never seen them, so have been unable to test.

If you need to look at the Peerlink range its in the Peerless pdf catalogue and the Grade B are in the section for G8 and G10 lifting components. The Grade A, half the strength, are in the marine section and look identical - confusion reigns! Its no different with Crosby, their Grade A shackles are G209 and their Grade B are G209 - A. Interestingly many of the Chinese have adopted Crosby and call their shackles G209 type - flattery Crosby do not really need.

I use the Grade B, its a bit of overkill, as the lifting industry all point out that if side loading a shackle at 90 degrees then the shackle WLL should be reduced by 50%. But they cost peanuts, even in Australia, and its hardly worth compromising the strength of the rode for a few Dollars. I know of cases where shackle failure looks, you never know, as if the shackle was side loaded.

I only quote 3/8th" for convenience.

I had thought some might use different connectors, like hammer links - obviously G7 is not flavour of the month.

Jonathan.

 

[vyv_cox]

Be very careful about the postage/shipping costs. I almost bought a couple of West Marine C-links to test. They were less than $5 each, seemed to be hardened and tempered, so likely to be OK. I was just about to press the button when I noticed that shipping was going to be $70!