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Old 15-05-2007, 01:09   #16
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23000lb boat on 1/4" G4? Feel free but please don't anchor anywhere up wind of me unless you're very skinny with no windage, even then I won't be happy.

Bear in mind all the Hi-test has a lower safety margin than the BBB. In all the world, US excepted, a 1/4" G4 chain (Hi test) has a WLL of 1500lb round figures or 25% of it's break load. The BBB (a G3) a WLL of 1760lb again 25% of break. Not to mention they would also be called 6 and 8mm but that's another story . Note - numbers close as due to swapping from metric to the old way and back again in places.

Hi-Test is a marketing phrase, it is not anything that special. There is a reasonable amount of smoke and mirrors by the spin doctors involved.

It's all not just about the strength. The loads chains can handle dis-proportionalty increase with the size of the chain, assuming the same grade. I'm of the mind that the 5/16", in this case, would be safer than the 1/4" even though the smaller is stronger or appear so at least. Working on the 'it's stronger so it's better theory' would mean you would be better off again with a 3/16" G7 chain. Obviously that is ludicrous.

The higher the grade the lower the tollerance to any shock loads. The smaller the chain the higher the chance of shock loads. Shock loads are major killers of much boat equipment.

So effectively going down to the 1/4" from the 5/16" you would be;
making your anchor chain more prone to shock loads
decreasing your chains ability to handle shock loads
decreasing your safety margin
decreasing your chains ability to help the anchor
decreasing any dampening you get from the chain
Will have to lay out more to get the same performance
decreasing the weight in the bow
spending more money
and a few other small fringe things, mostly not good.

As I see it one good thing is being outweighed by 7 + bad things.

An interesting FYI. I'm in NZ and do masses with the visiting cruisers. We swap out their chains often. For a US boat to stay with the same or go down a size is exceptionally rear. Going up one size is common and often down to a G3. Could it be that once they have spent some time in the out of the way ocean they may have realised the benefits of small supposedly stronger chains are more a myth than a fact?

If you stick with the 5/16", a reasonable size for a disp. of that size, you can anchor by me and I'll even shout you a cold beer or 3

Edit - A US G4 is the same as a NZ, French or WhyKickaMooCow G4.
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Old 15-05-2007, 03:17   #17
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I am very uncomfortable with the appearance that I am advocating smaller chain.

For the reasons cited by Gmac (one of our resident chain experts), and according the principles explained in Al’s “Tuning an Anchor Rode”, I do believe that, within the bounds of practicality, BIGGER IS BETTER.
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Old 15-05-2007, 03:24   #18
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If you have GREAT insurance you can anchor upwind of me!!

For the few extra pounds of weight, go with the heaver chain. Use less and get a good rode for the deeper water if you want to.
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Old 15-05-2007, 06:17   #19
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GOOD FEEDBACK!!

l thought it would bring a few sleepers to the surface with the topic.
Though l have never gone into the subject with such detail and science l could not in all good conscience place 1/4" chain on my beloved Wind Rose ll.
5/16" is what l use and is what l shall continue to use, as l have often said..."what price a good night sleep?"
Thank you again to all who responded and for the educated debate.
Dave
Wind Rose ll

PS. You may also sleep soundly if l anchor upwind of you.
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Old 15-05-2007, 08:23   #20
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GMac...notwithstanding Dave's decision, can you explain why the HT 1/4" inch chain is rated with a higher working load in the US than the rest of the world and is it ONLY this size & type that is similarly "over-rated" this way?? This is the first time I have heard this and I accept Gord's word that you are the "expert"...Just want to understand what is going on and what ratings CAN be relied on.
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Old 15-05-2007, 08:39   #21
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Don't use HT in that context, the acronym does not mean hi-test but high tensile, which is not what is being talked about...

Hi-test means just that; it is rated to a higher working load. That's not a bad thing but it does mean you can't compare the SWLs like-for-like to most other chains. You need to compare the breaking or yield strains.

In short, most of the world uses a 4:1 safety margin applied to the breaking strain to get the SWL. Hi-test does not use the same ratio. GMac may be able to tell you what the hi-test is in this case.
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Old 15-05-2007, 08:46   #22
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5/16" G3 has a WLL of 1900#, and an Unltimate Strength of 7600# (1900 x 4),
whereas
1/4" G4 has a WLL of 2600#, and an ultimate Strength of 7,800# (2600 x 3).
If the same factor of 1:4 were applied to G4, it would have a comparable WLL of 1,950# (for 1/4"),
still comparing favourably to 5/16" G3 (though lighter, for good or ill).
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Old 15-05-2007, 08:47   #23
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Quote:
Originally Posted by wind rose ll
l currently have approx 130 ft of 5/16 BBB chain and comparing it to 1/4" Hi-Test chain find the 1/4" to be stronger...l would like to increase my chain length and want to "sound the board" for opinions before l purchase the 1/4", l have capstains for both and my boat weighs 23000lbs loaded.
Dave
I don't necessarily agree that there is a problem with the 1/4", although I think you would need to go to high tensile (not hi test) to maintain a decent amount of strength, but I notice you also want to increase the chain length. The answer will depend to some degree on your intended anchoring, particularly how deep the water usually is, and what you have behind the chain.

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Old 16-05-2007, 00:58   #24
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Quote:
Originally Posted by camaraderie
GMac...notwithstanding Dave's decision, can you explain why the HT 1/4" inch chain is rated with a higher working load in the US than the rest of the world and is it ONLY this size & type that is similarly "over-rated" this way?? This is the first time I have heard this and I accept Gord's word that you are the "expert"...Just want to understand what is going on and what ratings CAN be relied on.
Expert?? No more just a sad bloke who has spent too much time fondling the bloody stuff. Some of the associated info just seems to have stuck in the old grey matter

It's not only that one or chain alone really, the US runs quite differant in many boat items and many others things but we won't go down that route incase someones gets rude or bombed. Why? Personally I think it is just the great american marketing thing.

Basically US made HiTest are bloody good chains so don't stress about that side of things, you do pay through the nose for it though. That's just the way it seems to be with lots of US gear. We use lots of US made rope and while top end quality it costs at least twice most others in the premium end.

When they test the Hi-Test they push the Proof Load right up close to Break load. The WLL is 1/2 the proof load. Generally the world use's 1/2 the break load as Proof Load so the WLL is a 1/4 of break.

Ya whot the Load to what? I hear. Chain loads 101

Bloke makes a chain out of a steel. The steel is a certian grade so Bloke can figure out a rough end result load. The chain is normalised and so on to get a finished Grade. The Grade is like most grades i.e big, small, whatever. In the case of chains we have grades from 1 thru 100 round figures as there are some real specials out there but you'll never use them. The Grades usually jump in lots of 10 hence we get Grade 30, Grade 40 and so on.

Grades below 30 are not that common for the likes of the recreactional boater. The most common, by a very very big margin, is Grade 30, this is what 95+% of cruisers are on. Then we get Grade 40 or what the US calls Hi-Test (actually most is G43 but I'm rounding numbers for ease). Each 10 jump in grade roughly equaly a 25% strength increase. So round figure a G4 is 25% stronger than a G3, a G5 is 25% above a G4 or 50% above a G3. I hope I'm making sense here.

Grades you'll find usually -
G3 - very very common and the most common used in anchor chains.
G4 - Quite common and used by a few as anchor chains, mostly Americans. This is not a bad thing.
G5 - fading away really and not easy to get anymore.
G65 to G7 - The one most loads are tied onto trucks and stuff like that. Usually not galvanised. There are only 3 places who make this galvanised for anchor chains, we know of. Maggi Aqua7 (Italy), A Swedish crowd who don't deal with the public and Acco/CM does some. While bloody strong it is a Hi Tensile, hates shock loads, don't ever re-galvanise it and costs a good moonbeam a foot.
G8 - the stuff hanging off cranes and fishing boats hauling nets. Never galvanised, usually painted black or yellow or red (for no appearent reason).
G100 - Serious cranes and bloody big fishing boats. Never galvanised, usually painted (a nice blue or red but again for no appearent reason so don't rely on colours to identify).

As a general rule using a Grade 50 or above on a anchor chain is silly. Just don't need the strength as the bits on the ends (boat and anchor) just will never get to the same loads.

Loads -
Break load - The load the chain breaks at. Usually the chain will break well above this load but never rely on it doing so, it may just not.
Proof Load - The actual load applied in the factory during the testing process. This is usually 1/2 the break load.
WLL - 1/2 the Proof load.

So what the US Hi Test guys do is bump up the Proof Load to give an increased WLL. Then the marketing department goes hard out saying "Look at our high WLL, isn't our chain that much better". As most people don't know the jiggerypokery that has gone on behind the scenes they think it is massively stronger than the rest. Quite cunning really. The effective end result is many running around paying more and thinking they have masses more security so go down in chain size. Also the Saftey margin is a lot less than what it appears.

In the rest of the world G3 and G4 chains run a 4 to 1 saftey margin so show lower WLL's. Many US chains run the same, the BBB is one. This trick bit is nearly the Hi Test only.

So if that makes sence you hopefully have a better idea of what's going on.

Just to make the American audience feel a tad more out of step with the rest of us, the Grade names changed around the world a few years back to letters. A Grade 30 in the US is a Grade L elsewhere, a G40 is Grade M, a Grade 50 is a Grade P and so on. So if one day you pick up a chain and see, for example, a 'L' stamped on it you can now big note a bit and say "Oh yeah a Grade L, what you in Texas call a grade 30"

Oh at yet another US thing, sorry all you guys , sizing used in the US is generally differant from the rest as well. This is the phyisical size of each link. Many can be swapped straight over but many can't. A US 1/4" G4 for exapmlpe can be swapped directly for a DIN766/A 7mm chain, a 3/8" US can be swapped for an 11mm DIN so it not all that bad. But do remember if you load up with some US chains and lose it in the Med, for example, a replacement may have to come from the US or you do a gypsy swap.

Obviously all of the above is a bit 'general' and there are many other loads, chains and so on used but almost all of those are specialised and you'll never see or use then.

THE BIG NOTE - ALL OF THE ABOVE APPLIES TO GOOD QUALITY MADE CHAIN SO YOU CAN NOT INCLUDE MOST OF THE ASIAN MADE PRODUCT. While they are getting their act togeather and quite quickly their chains still have a very high random lemon factor. By that I mean, lower loads, poor or non-existant calibration and rusts quicker (they leave too many dashboards in the steel when re-making it). It is not uncommon to find just one link not even welded. Spooky spooky spooky. When your mate says buy here it's 1/2 the price be cautious, it not 1/2 the price for no good reason. It maybe good but it usually is asian made.

Quick note: 1st Chain Supply in the US has some bloody cheap chains at times. They just seem to do good deals and good on them for doing so. I wouldn't even know what State they are in or them from a bar of soap actually but have had a few people ask if they are any good. I do know they sell good quality gear though, I checked

Absorb that lot you lot
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Old 16-05-2007, 03:14   #25
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Expanding on GMac's excellent reply ...

The Ultimate Tensile Strength of a material is calculated by dividing the area of the material tested (the cross section) by the stress placed on the material, generally expressed in terms of Newtons per square millimeter (N/mm2), or pounds per square inch of material (PSI).

1 N/mm2 ≈ 145.04 psi
1 psi ≈ 0.006895 N/mm2

Common North American (ASTM/NACM) chain grade numbers are actually 1/10th of the tensile strength or (1/100th for single digit markings), hence G30 is actually G300 etc.

The DIN series is a standard for size and strength set by the International Standards Organisation (ISO). The DIN series has been adopted as the world standard for chains, North America excepted.

The standardized grade designations are:
ASTM: (actual, DIN, Vernacular)
carbon steel chains
G30: (300, L , Proof, BBB)
G43: (430, M, Hi-Test)
G70: (700, Transport/Binding),
alloy steel chains (for overhead hoisting)
G63: (630, S)
G80: (800, T)
G10: (100)

Some chain definitions:

Breaking Strength/Ultimate Strength:
Breaking Strength is the average force at which the product, in the condition it would leave the factory, has been found by representative testing to break, when a constantly increasing force is applied in direct line to the product at a uniform rate of speed on a standard pull testing machine. Proof testing to twice the Working Load Limit does not apply to hand-spliced slings.
Remember: Breaking Strengths, when published, were obtained under controlled laboratory conditions. Listing of the Breaking Strength does not mean the Working Load Limit should ever be exceeded.

Proof Test
The term "Proof Test" designates a quality control test applied to the product for the sole purpose of detecting defects in material or manufacture. The Proof Test Load (usually twice the Working Load Limit) is the load which the product withstood without deformation when new and under laboratory test conditions. A constantly increasing force is applied in direct line to the product at a uniform rate of speed on a standard pull testing machine.

Working Load Limit/Safe Working Load:
The Working Load Limit is the maximum load which should ever be applied to a chain, even when the product is new and when the load is uniformly applied - straight line pull only. Avoid side loading.

Design Factor/ Safety Factor]:
An industry term usually computed by dividing the Breaking Strength by the Working Load Limit and generally expressed as a ratio. For example: 3:1 (where the breaking strength is 3 times the WLL), or 4:1 (where the breaking strength is 4 times the WLL).

The more commonly used Design Factors are:
4:1 G30, G70, G80
3:1 G40/43

Shock Load:
A load resulting from rapid change of movement, such as impacting, jerking or swinging of a static load is referred to as shock load. Sudden release of tension is another form of shock loading. Shock loads are generally significantly greater than static loads. Any shock loading must be considered when selecting the item for use in a system.

More information:

“Welded steel Chain Specifications”
From The National Association of Chain Manufacturers (NACM)
http://www.nacm.info/Downloads/NACM_Welded.pdf
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Old 16-05-2007, 12:16   #26
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Thanks GMac & GMay! Lots of good info...did you guys go to school with Tolstoy?? (G)
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Old 17-05-2007, 00:28   #27
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Gezz Gord, how to you hold all the info you do? My por old head would explode with only 1/2 the good stuff I've seen you post.

Nice one above there and a bit tidier than mine

A quick note to the US audience and Lewmar users here. CM/Acco and Lewmar refer to some of their chain sizes as 'ISO'. As Gord rightly pointed out the ISO is an organisation that oversees the many standards so ISO is not a standard in it's own right as such. These ISO sizes are a mix usually of DIN and EN (mostly 818-3 but with a splash of -2). If you get one of those you may have to note the pitch measurement so you can get a gypsy to fit. Some of the winch makers struggle with that one and a pile more of their sellers

Don't stress about all these DIN766/A, EN818-3's and so on, there's piles of them out there. Just pick a chain that matches your gypsy with the load you like and all is good. The guys selling you the winch should know what sizes fit what and so on.

'Pitch' - basically the internal length of each link of chain. It is actually measured a bit differant but the answer should be the same. The Pitch measurement is the important one when fitting to winches, besides the wire size obviously. 1mm differance in pitch can be the differnace between a nice quiet smooth runner and a gypsy trasher. Sorry, I have no idea what 1mm is in that old measurement system, damn small anyway

'Wire size' - the size of the wire bent to make the link i.e a 3/8" chain is made from 3/8" wire, simple really. The width of the links don't usually make any differance as most gypsys will have a large tollerance with that measurement.

There you go. Choose well, size right and boat safe

Tolstoy?? Wasn't he the Russian dude who designed that wierd banana shaped boat for the Whitbread Round the World race a few years back? I know the name and have this un-easy feeling I just made an arse of myself..... yet again
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Old 17-05-2007, 07:59   #28
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I've been mulling over the exact same decision as the original poster, though on a much lighter boat.

Firstly, thanks GMac for all the information, especially about the 3 vs 4 safety factor for G43 vs G30. It does raise a question you might be able to answer.

Is there any science behind the different safety factors? In my experience, these factors are usually based on the underlying probability distribution of a measurable property, in this case breaking strength. The tighter the distribution, the smaller the safety factor can be. Is there any reason that the distribution for G43 would be different from G30? I know the metallurgy is different, but I would think the manufacturing process would be the same. Possibly less variation in weld strength for G43?

The other possibility, as GMac suggests, is that it is just marketing nonsense designed to sell more expensive chain.

It is interesting to note that the proof test load is the same (half the breaking strength) for both grades.

Last question: Based on peoples experience, when chain does fail, what is the usual failure mode? (material, weld, etc) I realize that many ground tackle failures are due to other elements, such as shackles or swivels. I'm interested in understanding how chain actually fails.

I am always suspicious of round numbers when related to physical properties. Why a safety factor of exactly 4 or 3? Why not 3.1416 or 2.718? It leads me to believe there isn't much science involved.

This has been a very useful thread. Thanks to all who contributed.

Charlie
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Old 18-05-2007, 01:21   #29
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I just don't know why the US, and it's only the US, run the G4 at those margins. Nobody has been able to give me a firm answer and I've asked many.

Sceptical I maybe but the great US marketing machine looks to have had it's fingers in there. It's about the only thing that stacks up. I could be very wrong but there just does not appear to be any other reasonable reason. When you think about it, it is a bloody clever idea which many have fallen for. Can't blame the punters for that though.

There are a range of safety margins out there and the same chain can have more than one depending on end use. A bit like ropes really. As a general rule most run a 5 or 6 to 1 safety margin when used for everyday stuff like halyards, anchor rodes and so on but the exact same rope when used to climb on it must be rated at 10 to 1.

I'm guessing margins of round numbers are just easier. Our Maggi DIN chain, for example, is listed in the Tech Specs with 2 loads. One is according to the DIN standard, 8mm is 3200kg for example, as specified by the ISO. But then Maggi say the actual break load (of their chain) is 4000kg. We have busted lots over the years (boys and a a 200 tonne ram, More Power Tim ) and none has been below 4300kgs. So they have 2 WLL's, one according to DIN spec and one according to actual results, a 200kg differance. Mind you the EU has also a pile of overpaid idiots just making stuff up to keep their job just like most countries so silly **** does and will keep happening.

The loads and working of are an industry norm thing and I'm guessing the Hi Test WLL being 1/2 the proof load is just to keep in sync with that. Maybe could be read as 'easier to defend in court if it goes bad'. A cynical prick don't ya think

Chain is one of the worlds oldest manufactuered products, right back there with bread I'm told. So you would think that it's properties should be pretty well known by now. Well at least until we all got sucked into the Global Village and have one or 2 countries taking over masses of production backed by 'brand marketing' in the search for ever bigger profits.

Chain failure. One major cause in NZ is me, I have major issues with marketers (not that you'd know )and just love busting stuff

Chain 'should' break on one of the 4 corners just where the bend starts to go straight. It should never break beside the weld or in the weld itself. That is a big naughty if it does. Chinese chain almost always pulls apart the weld, assuming it was actually welded in the first place. Sometimes they just pull a whatever size chain it is section out of the end of the link, again a naughty.

Lower grade chains stretch and will stretch a lot before finally going pop. A G3 can easily double in length. Each link will get to a figure 8 shape before going. So a good reason to use lower grades is that if you do over cook the load it should be very noticable by Mk1 eyeball, winch jambing up and things like that.

Hi tensile chains can stretch next to nil before popping. Hence you get no warning, it just goes and it's all over rover. Snaps like a dry twig but with a more bloke type tone, sounds quite cool actually. The higher the tensile the less stretch and better bang. Try banging a 20mm G80 without getting a slight boner, a sad thing to say but the noise is absolutly fantastic, a bit like that old Chevy V8 noise when you were 16

Don't panic though, chain failure is very rear when used as an anchor rode. The usual failures in this situation are - crap chain, undersizing and the bloody idiot using it i.e bouncing the boat on it trying to get the anchor back, re-galving 20 times. So to minimise this possible problem - don't buy cheap nasty, don't get a silly on and grade up while downsizing and use it in conjunction with your grey matter. Replace when any part of a link is 10% or more less than the starting size. Saying all of that, chain (in anchor rodes) failures are increasing but almost totally due to quality decreases from some sections of manufacture. As a rule the anchor or a boat part will fail first.

NOTE and quite a biggy - ALL LOADS ON CHAINS and ropes are done when new in a lab and pulled in a slowish controled manner. When you start using them the loads will derease. If you damage them in any way the loads decrease. UV will make the loads decrease, in rope anyway. Many things will decrease loads over time. If you shock load them it will hurt if not bust them. Drop 1000kg 1 metre and 9000kg is needed to stop it. Spooky don't you think. Anyone on tiny hi tensile chain feeling a tad worried about now?

One phrase that sends the willies up my back - "I've had it for 20 years, re-galvanised it 6 times now and it's perfectly fine". I think the chances are quite the opposite often.

Good golly, what a pile of educated punters this forum will now have. Hate to see someone try to pull a dodgy on you during your next chain purchase

Beer O'clock, catch ya all later,
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Old 18-05-2007, 02:53   #30
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I’ve never actually seen an anchor chain failure. I have seen failed hoisting chains.

It's good practice to inspect your anchor chain each time you deploy it.

As Gmac indicated, when a chain is proof tested, the load is put on gradually under ideal conditions (in a straight line, with no twists in the chain's linear orientation).
In use, the strength of your anchor chain can be compromised in a number of ways. First, there is the normal wear and tear. Small scrapes expose bare steel that then begins to rust. The links gets smaller from rust and abrasion. The chain can be twisted or the load put on one individual link at an angle because the links are caught on an underwater obstruction.

Generally, any perceptible visible defects should be cause to remove the link, or chain, from service.

Check individual links, especially the crowns (where one link bears on another) for signs of damage such as:

- wear (max. 5 - 10%)
- stretching (max. 2 - 6%%)
- deformation (bends & twists ~ max. 5 degrees off plane),
- cracks or gouges (any visible* stress corrosion cracking, or corrosion fatigue cracking**)
- corrosion (visible pitting)


* Clean chains with a non-acid/noncaustic solvent so that marks, nicks, wear and other defects are visible.
** static load conditions tend to promote stress corrosion cracks and cyclic load conditions result in the formation of corrosion fatigue cracks.

Shock loading must be minimized. Always use a snubber, on an all chain road.
Brittle fractures are generally attributed to a high shock load abnormal event loading condition, rather than from a significantly defective weld condition.
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