High Tensile Chain Hydrogen Embrittlement

[akio.kanemoto]

Howdy,

I am currently looking for an anchor chain for my boat, as soon-to-be a full-time cruiser. However, my boat is a converted racer... meaning that while I want a LOT of chain, I can probably only deal with 100kg (220lbs) at the bow and that's stretching it and there's no way to carry it further aft.

So I want the strongest chain that I can get for the lightest weight possible.

Boat is 40ft, light(ish) displacement and I was hoping to get away with 8mm (5/16") high tensile chain. This means about 66m (~200ft).. which I can extend with nylon if required in a worst case scenario.

However, when I called the local chain manufacturer here (PWB Anchor - PWB Anchor - Chains, Fittings, Hoists, Australia, Melbourne, Materials Handling, Marine, Transport, Agriculture, Entertainment, Mining, Construction, General Engineering, ISO 9001), they told me that high tensile chain cannot be used for marine use as it will suffer from "hydrogen embrittlement" and fail. Their high tensile stuff is called "Hercalloy 800" and 8mm has a WLL of 2 tonnes (4400 lbs).

So after having read through a million cruising experiences of others swearing by high tensile chain including Mr. Estarzinger who hangs around in Really Hard Places(tm)... I am baffled.

The chain that is recommended in Australia is something called "Grade L"... I have since come to think that perhaps there is just a naming convention difference between AU and USA?

Could it be that when (generally) American folk refer to "High Tensile" chain and "Grade 70" etc... could they be referring to "Grade L" here?

The only thing that kills my argument here is that the Grade-L 8mm chain has a paltry WLL of 640kg (1410 lbs).. (but mentions a design factor of 5:1... breaking load?)

Yet another fly in the ointment here is that the person from Pwbanchor.com.au also referred to a "Grade T" chain that is often used but is not recommended... to me, this looks like their "transport" chain, but WLLs are only given for "lashing capacity"... for which 8mm yields 4 tonnes (8800 lbs).. which sounds much better, but I'm totally confused now.

Can somebody shed light on what Grade L is and whether it is what everybody on the other side of the ocean refers to as "high tensile"? Should I be looking at breaking loads of WLLs? Any other thoughts? Recommendations?

Help! I'm going crazy!

[colemj]

"HT", as used by most in the context of anchor chain, means "high test" and not "high tensile". High test simply means that the chain has been tested at a higher working load. However, it has the same breaking load as other chain in its class. It is a bit of a marketing gimmick.

Grade L is the new denomination for what used to be Grade 4/40/43 - what most refer to as HT

High tensile is another beast altogether and higher tensile chains are not really appropriate for dynamic applications like anchoring. You can probably get by with a G70, but not higher. I suspect that using the term high tensile when talking to a chain supplier had him thinking of true high tensile chain, so his response was correct as far as he understood. Call him again and ask about high test instead.

BTW, we are on a relatively heavy 40' catamaran and are using 5/16" G43 high test chain. Personally, I think you would be fine with it also.

Mark

[Pblais]

In the US G40 is what we call high test. G40 1/4 inch is the same WWL as 3/8 inch (10mm) BBB. That would be 2600 lbs. and about as recommend for a 40 ish foot boat. The fact that you used to be a racing boat does not matter once you load all the crap you need to cruise. This is not the same grade as "lifting" chain. You don't want that kind of chain for cruising.

I think the problem I see is just what is grade "L". It's not something I have know of. 10 mm chain would be my preferred choice. The bulk of the chain allows to drop 160 ft in the water without an anchor on a calm day and never move. In the US we call it G40 "high test" and you could be good 1/4 inch with that.

[donradcliffe]

Peter and Craig from Rocna will set you straight on the local chain

Chain (Rocna Knowledge Base)

[foggysail]

I am using 5/16" HT on my boat only because Maxwell does not offer a 1/4" gypsy fror my HWC2200 windlass.

But one thing for sure, if they did, I would chuck the 5/16 stuff and go with the 1/4" HT. Another thing for consideration................ those who are using very heavy chain such as 5/16 and larger, do you really think your boat is structually strong enough to withstand the breaking force needed to cause chain failure????

I for one firmly believe there would be a LARGE chunk of fiberglass flying through the air attached to the chain before the chain would fail. Anybody want to test their boat??? LOL of course!

Foggy

[Mark Zarley]

Ok, Lets talk pounds per ft. or per 100ft. What is the most impt part of anchoring? Keeping the chain on the bottom! That's right keep that chain on the bottom , otherwise it pulls up on the anchor, then the anchor breaks loose, then you drag. So want to feel safe at anchor, use enough heavy chain to keep it on the bottom or have a kellet handy. It is not about breaking strength it's about having enough weight to keep a laterial pull on the anchor.

[Pblais]

It is not about breaking strength it's about having enough weight to keep a laterial pull on the anchor.

Anchoring 101 - Keep the hook in the bottom until you want to leave.

[akio.kanemoto]

Thanks for the replies, greatly appreciated.

Regarding weight of chain - I subscribe to the Alain Fraysse school of thought, meaning weight of chain is largely irrelevant in difficult situations since it comes off the bottom anyway:

Tuning an Anchor Rode

Which means that chain strength is what I'm keen on.

Regarding boat structural strength - I have SERIOUSLY beefed up the bow and have evenly distributed stress points etc etc so I'm pretty comfortable in wagering that my bow would come darn pretty close to taking the breaking load of the 8mm chain.

[akio.kanemoto]

Originally Posted by colemj

"HT", as used by most in the context of anchor chain, means "high test" and not "high tensile". High test simply means that the chain has been tested at a higher working load. However, it has the same breaking load as other chain in its class. It is a bit of a marketing gimmick.

Grade L is the new denomination for what used to be Grade 4/40/43 - what most refer to as HT

High tensile is another beast altogether and higher tensile chains are not really appropriate for dynamic applications like anchoring. You can probably get by with a G70, but not higher. I suspect that using the term high tensile when talking to a chain supplier had him thinking of true high tensile chain, so his response was correct as far as he understood. Call him again and ask about high test instead.

BTW, we are on a relatively heavy 40' catamaran and are using 5/16" G43 high test chain. Personally, I think you would be fine with it also.

Mark

That's comforting to hear - what length of chain do you carry by the way?

[craigsmith]

Originally Posted by colemj

Grade L is the new denomination for what used to be Grade 4/40/43...

No it isn't, Grade M is G4. Grade L is low tensile G3, or the equivalent of what Americans know as BBB or proof coil. The other Australian grade is P, which is G5, I don't know of an equivalent for G7.

Originally Posted by colemj

- what most refer to as HT

And totally incorrectly. HT is an engineering abbreviation which means high tensile. Americans innocently or not misuse the term because of the confusion with "high test", a marketing gimmick as you imply which was obviously intended to create just such confusion.

~

Originally Posted by akio.kanemoto

Regarding weight of chain - I subscribe to the Alain Fraysse school of thought, meaning weight of chain is largely irrelevant in difficult situations since it comes off the bottom anyway:

Good for you. Ignore the traditionalists You are on the right track.

The simple answer to the above confusion is to insist on using the numbers, which equate to the tensile strength of the steel, and there can be no arguments. G7 has a tensile strength of 700 MPa, over double that of BBB/G3.

The 800 grade that PWB suggested does sound a bit over the top. If there's not a galvanized version available you should probably move on.

Now, hydrogen embrittlement: yes a possible issue, however, there is a bit of myth and lore surrounding hydrogen embrittlement and it's something that gets blamed for a lot of problems but frequently unfairly (and in ignorance of the true causes). I am not a galvanizing expert, but most will tell you that hydrogen embrittlement is not much of an issue in steels with tensile figures below 1000 MPa. I would think strain-age embrittlement is more of a concern with chain. Look it up on Google if you're currently developing an interest in HDG technology.

The point is that G70 chain can be safely galvanized, is safely galvanized and sold by a number of reputable brands, and can also be re-galvanized but only with significant care. This is really where it's the biggest issue for you - an ignorant galvanizer can ruin your chain if they don't know what they're doing. But, lots of folk end up just replacing chain anyway.

Finding high tensile galvanized chain is a bit tricky, in the US ACCO/Peerless sold it as "transport chain", in Europe Maggi make a brand called Aqua7 which is available in New Zealand at least - worst case scenario you could order it from across the Tasman. Throw in a few anchors and shipping won't cost that much on a per-unit basis. Or, phone around Australian chain suppliers (not necessarily marine specialists - in fact don't even bother with chandleries to start with) and ask them if they sell Maggi. If they don't have it in stock they can probably add it to their next order if you're not in a hurry.

Refer to the link Don R gave above for sizing table. You should size G7 with a slightly higher WLL than G4, to allow for its reduced handling of shock loading. However WLL is WLL and all chain breaks when it breaks, the particular failure mode (stretch or snap) is a bit of a non-issue.

[colemj]

Originally Posted by akio.kanemoto

That's comforting to hear - what length of chain do you carry by the way?

Right now 125', but we are going to 200'.

Originally Posted by craigsmith

No it isn't, Grade M is G4. Grade L is low tensile G3, or the equivalent of what Americans know as BBB or proof coil. The other Australian grade is P, which is G5, I don't know of an equivalent for G7.

My bad. I knew the terminology had changed and should have double-checked before posting.

Mark

[Mark Zarley]

If I only wanted 220 lbs of chain weight in the bow , and I was going to anchor I would want all 220 lbs in the water. If it was in 50 ft of chain even better, the rest rode. Tensil strength with a lite chain is a moot point , the hook will never stay set long enough to even begin to reach the breaking point. Sort of like trying to anchor with no chain at all, just rode. I agree that when conditions get really bad it is more difficult to keep your anchor, anchored. That is when we will deploy all 200 ft of our 1/2'' BBB . If the bottom is good we are good. The weight of the chain still onboard after anchoring is wasted weight.

[akio.kanemoto]

Originally Posted by craigsmith

No it isn't, Grade M is G4. Grade L is low tensile G3, or the equivalent of what Americans know as BBB or proof coil. The other Australian grade is P, which is G5, I don't know of an equivalent for G7.


And totally incorrectly. HT is an engineering abbreviation which means high tensile. Americans innocently or not misuse the term because of the confusion with "high test", a marketing gimmick as you imply which was obviously intended to create just such confusion.

~


Good for you. Ignore the traditionalists You are on the right track.

The simple answer to the above confusion is to insist on using the numbers, which equate to the tensile strength of the steel, and there can be no arguments. G7 has a tensile strength of 700 MPa, over double that of BBB/G3.

The 800 grade that PWB suggested does sound a bit over the top. If there's not a galvanized version available you should probably move on.

Now, hydrogen embrittlement: yes a possible issue, however, there is a bit of myth and lore surrounding hydrogen embrittlement and it's something that gets blamed for a lot of problems but frequently unfairly (and in ignorance of the true causes). I am not a galvanizing expert, but most will tell you that hydrogen embrittlement is not much of an issue in steels with tensile figures below 1000 MPa. I would think strain-age embrittlement is more of a concern with chain. Look it up on Google if you're currently developing an interest in HDG technology.

The point is that G70 chain can be safely galvanized, is safely galvanized and sold by a number of reputable brands, and can also be re-galvanized but only with significant care. This is really where it's the biggest issue for you - an ignorant galvanizer can ruin your chain if they don't know what they're doing. But, lots of folk end up just replacing chain anyway.

Finding high tensile galvanized chain is a bit tricky, in the US ACCO/Peerless sold it as "transport chain", in Europe Maggi make a brand called Aqua7 which is available in New Zealand at least - worst case scenario you could order it from across the Tasman. Throw in a few anchors and shipping won't cost that much on a per-unit basis. Or, phone around Australian chain suppliers (not necessarily marine specialists - in fact don't even bother with chandleries to start with) and ask them if they sell Maggi. If they don't have it in stock they can probably add it to their next order if you're not in a hurry.

Refer to the link Don R gave above for sizing table. You should size G7 with a slightly higher WLL than G4, to allow for its reduced handling of shock loading. However WLL is WLL and all chain breaks when it breaks, the particular failure mode (stretch or snap) is a bit of a non-issue.

Wow, that's quite a bit of info there. Thanks muchly.

OK, so I sent an email to Maggi and asked for their Australian distributor.. still waiting on that one... but in the meantime, have called another chain manufacturer Serafini in QLD...

Them: "transport chain is not suitable for anchoring - we recommend Grade P..."

Me: ??!??! "ok, so what is it's tensile strength?"

Them: "don't know... working load for 8mm is 1.28 T"

Me: "err... does that mean that the tensile strength of the steel is 700mpa by any chance?"

Them: "don't know.. we recommend only grade p and stainless for anchoring"

...hmm... did I mention that it's AUD30/m + AUD230 freight to Sydney from Brisbane?

On the Rocna, I'm planning on buying only one.. so I might pass on a containers' worth to save on the shipping of the chain.

I don't suppose you have the contact details of anybody who does know what 700mpa means and can sell me a chain (preferably cheaper than $30/m too!!! eek!)

[Healer52]

Originally Posted by akio.kanemoto

Wow, that's quite a bit of info there. Thanks muchly.

OK, so I sent an email to Maggi and asked for their Australian distributor.. still waiting on that one... but in the meantime, have called another chain manufacturer Serafini in QLD...

Them: "transport chain is not suitable for anchoring - we recommend Grade P..."

Me: ??!??! "ok, so what is it's tensile strength?"

Them: "don't know... working load for 8mm is 1.28 T"

Me: "err... does that mean that the tensile strength of the steel is 700mpa by any chance?"

Them: "don't know.. we recommend only grade p and stainless for anchoring"

...hmm... did I mention that it's AUD30/m + AUD230 freight to Sydney from Brisbane?

On the Rocna, I'm planning on buying only one.. so I might pass on a containers' worth to save on the shipping of the chain.

I don't suppose you have the contact details of anybody who does know what 700mpa means and can sell me a chain (preferably cheaper than $30/m too!!! eek!)

Well, 700 MPa is 101,526.4163900 PSI, if that helps.....But if these guys don't know the specs on their chain, I might start looking for another vendor.

[craigsmith]

Originally Posted by akio.kanemoto

OK, so I sent an email to Maggi and asked for their Australian distributor.. still waiting on that one... but in the meantime, have called another chain manufacturer Serafini in QLD...

Them: "transport chain is not suitable for anchoring - we recommend Grade P..."

Me: ??!??! "ok, so what is it's tensile strength?"

Them: "don't know... working load for 8mm is 1.28 T"

Me: "err... does that mean that the tensile strength of the steel is 700mpa by any chance?"

Them: "don't know.. we recommend only grade p and stainless for anchoring"

Grade P is G50 and I've only ever seen it in stainless. Strange that they'd recommend only that for anchoring, although ideal it's hardly realistic for the bulk of customers on account of the price as you can see.

I don't suppose you have the contact details of anybody who does know what 700mpa means and can sell me a chain (preferably cheaper than $30/m too!!! eek!)

If you mean in NZ, this outfit is probably your best bet. Here's the link to the page for 8 mm Maggi Aqua7:
http://www.chainsropesandanchors.co....ain-p-596.html
Deduct the included NZ GST (12.5%) for an export order. If your vessel is foreign flagged in transit you shouldn't have to pay Australian GST either so keep on top of that.
Phone them up and check re stock and shipping before placing an order. (No affiliation)
This is the Maggi catalog if you're interested:
http://pdf.nauticexpo.com/pdf/maggi-...4985-4218.html