For those that think S/S chain is a good idea

[Simi 60]

I have never used stainless underwater for what I thought were obvious reasons
Some think it's a great idea.
This from a FB cruising site

Somebody posted a warning against using SS anchor chains recently. I replied, I didn't make any bad experience with them recently. The situation has changed :-(.
I was caught in a 40kn blowout at Lady Musgrave Island a few days ago. As it was well advertised, I dropped 2 anchors - one on 10mm short link and another on 10mm long link SS chains.
When the seemingly uneventful show was over, I found no anchor on the short link chain and almost all welds on the long link one broken - the chain didn't part though.
I recovered the anchor and found the guilty link as well. The break was showing an old crack that developed deeper over time by an oxygen deprivation corrosion. The surface of the link had also a few hairline fractures. Examination of a number of other links on the chain found no other similar crack, what led me to a hope I had only one faulty link.
I attached a recovery buoy to the anchor, dropped it and gave it a decent jolt with the boat. The chain has severed with a loud bang...
The breakage on the link was showing the same pattern as on the first one. Anybody wants 30m of a nice shine SS 10mm chain? Cheap!
The problem is, SS doesn't age so much with years as with load cycles. There is no other mechanism producing higher number of load cycles than an anchor chain on a boat on choppy seas... Stainless steel chain is a deathtrap. Never again - maybe for "lunchbreak" anchoring in a calm water when I am in a full control, have recovery buoy on my precious anchor attached and a few hundred m drifting wouldn't be any issue.
What else to say?
"Have a SS chain? If so, think twice!"

 

[Simi 60]

I know that German made Ketter Walder "Cromox" is claimed to be a suitable S/S chain
But at over $21,000 AUD for 80m of 13mm chain that ain't happening

 

[rslifkin]

I know that German made Ketter Walder "Cromox" is claimed to be a suitable S/S chain
But at over $21,000 AUD for 80m of 13mm chain that ain't happening

Yup, there are 2 kinds of stainless chain. Inadequate ones and unaffordable ones.

 

[socalrider]

Terrifying! But agree - why on God's green earth would you use stainless for an anchor chain in the first place?!?

 

[Northern Spy]

Without a NDT report, the causation is merely speculative.

The term "stainless steel" covers a large metallurgical spectrum. Grade and alloy composition is important.

It is suspect that the failure is at the welds. Could very well be incompatible filler material or improper weld procedure.

That said, I see no need or value in a stainless steel anchor chain. Or anchor, for that matter.

 

[twistedtree]

The photo shows that the welds separated on many links. I would think you’d notice that when operating the windlass. And it would be very interesting to know who the manufacturer is.

 

[Simi 60]

The photo shows that the welds separated on many links. I would think you’d notice that when operating the windlass. And it would be very interesting to know who the manufacturer is.

You wouldn't necessarily notice it with crevice corrosion.
Could have been a decent amount of chain weld still intact holding links closed and running through windlass fine but during a blow broke the links.

Have seen the same in chainplates, rigging toggles even prop shafts
All looks good until it's not.
Die check reveals things to some degree.

 

[O C Diver]

The other side to stainless steel chain:

I used stainless steel chain on my charter boat for 20 years. I carried scuba divers to shipwrecks and short scope (1.25 : 1) grappled the wrecks with 40' of chain and a stainless steel grapnel. Above the chain was 1/2" twisted 3 strand nylon. I did this over 1,000 times in 20 years. Still have the chain and custom built grapnel.

So you ask, why? Drag galvanized chain across the bottom and up the jagged edges of a steel shipwreck and see how long the galvanize lasts. The chain would be rusting on my boat in less than a year.

Never had an issue with the chain, and it saw its share of shock loading with 1.25 : 1 scope. Usually had to cut off the first 50' of rope at the end of each season due to abrasion and shock loading. The short scope was so that divers could descend down to the wrecks, not swim forward hundreds of feet.

I remember buying the chain from Hamilton Marine in Maine 25 years ago at $$$ per foot. Proved to be a very good investment.

Ted

 

[jgwinks]

Stainless contains a lot of nickel and some chromium and other metals, that's what makes it "stainless". But those metals are not very strong and anything made of stainless is going to be substantially weaker than if it were regular steel. And that's without even considering welds, etc. IMO stainless is only appropriate for cosmetic stuff. Galvanized or bronze are better, but no one makes hardware like that anymore.

 

[Group9]

Terrifying! But agree - why on God's green earth would you use stainless for an anchor chain in the first place?!?

It's pretty and shiny.

 

[twistedtree]

It's pretty and shiny.

And practical reasons like is sheds mud much easier, piles in a tighter mound in the chain locker, and doesn’t shed rust all over the chain locker and foredeck.

I think what’s important is to get chain with the same or better WLL vs gaIvi chain.

In the original set of pictures, you could see many links where the weld let go. What’s unclear is whether that was due to overloading, or if poor welds and/or corrosion weakened the welds.

 

[backinblue]

Stainless contains a lot of nickel and some chromium and other metals, that's what makes it "stainless". But those metals are not very strong and anything made of stainless is going to be substantially weaker than if it were regular steel. And that's without even considering welds, etc. IMO stainless is only appropriate for cosmetic stuff. Galvanized or bronze are better, but no one makes hardware like that anymore.

I think that's more opinion than fact. If you look at the specs of high quality SS chain, it is in fact very strong. Besides the abrasion resistance and cosmetic reasons, there are another few reasons to want SS anchors and chain.

1) Mud does not cling to them nearly as much so the ground tackle comes up much cleaner.

2) Because the chain is more slippery, it falls and stores more easily.

3) If you have a SS anchor or swivel, the SS chain does not have the galvanic corrosion issue that galvanized does.

 

[Peter B]

I have never used stainless underwater for what I thought were obvious reasons
Some think it's a great idea.
This from a FB cruising site

Simi, the post you quote is confusing. He says (quoting the confusing bit), "...As it was well advertised, I dropped 2 anchors - one on 10mm short link and another on 10mm long link SS chains....When the seemingly uneventful show was over, I found no anchor on the short link chain and almost all welds on the long link one broken - the chain didn't part though".

Confusing, because he gives the impression the short-link chain was galvanised, yet when he retrieved that chain, he says there was no anchor on it. Suggesting it had also parted company at some point. Yet the stainless steel chain did not part - just had a lot of welds separate.

The overall conclusion would appear to be it was sh*ty cheap stainless, but at least it held - just long enough by the sound of it - but the galvanised chain broke at some point..? Anyone else confused as well..?

 

[BruceK]

Simi, the post you quote is confusing. He says (quoting the confusing bit), "...As it was well advertised, I dropped 2 anchors - one on 10mm short link and another on 10mm long link SS chains....When the seemingly uneventful show was over, I found no anchor on the short link chain and almost all welds on the long link one broken - the chain didn't part though".

Confusing, because he gives the impression the short-link chain was galvanised, yet when he retrieved that chain, he says there was no anchor on it. Suggesting it had also parted company at some point. Yet the stainless steel chain did not part - just had a lot of welds separate.

The overall conclusion would appear to be it was sh*ty cheap stainless, but at least it held - just long enough by the sound of it - but the galvanised chain broke at some point..? Anyone else confused as well..?

I agree Peter. Bad fortune/coincidence to set 2 anchors,one rode gal, the other ss,anchor separates from gal chain while the ss chain welds fail. Maybe poor conditions, 2 anchors were employed. But simultaneous different forms of rode failure raises "what was going on".

 

[twistedtree]

I agree Peter. Bad fortune/coincidence to set 2 anchors,one rode gal, the other ss,anchor separates from gal chain while the ss chain welds fail. Maybe poor conditions, 2 anchors were employed. But simultaneous different forms of rode failure raises "what was going on".

It seems to say that the 10mm chain was significantly undersized since two of them failed (in different ways). I think you could just as well conclude that SS is better than galvi because the galvi parted completely where the SS only partially failed. But I think the real conclusion is that 10mm was too small for the load, and that it really doesn't speak to galvi vs SS at all.


Full disclosure: I have 600' of SS chain in my locker waiting for a new chain wheel so I can put it into service. So I've picked my dance partner....

 

[Delfin]

An under appreciated feature of galvanized chain is that it presents resistance to dragging through the sea bed because it's rough. SS, not so much. It kind of acts like an underwater Jordan drogue with lots of points of drag, each small, but cumulative adding up, and especially so with cross link chain. Underwater photos of ship's ground tackle seems to confirm this. Yes, when it really blows the chain lifts, but in most anchoring situations, it's the chain that is anchoring the boat.

 

[Hippocampus]

I’m curious about the failure as well. 40k is miserable but not at all extreme. Not at all uncommon to see 40k when anchored to avoid being out as a front moves through or with a T storm. You’re talking force 8. Not storm or hurricane. Questions in my mind are:
Was the event brief like a tstorm or long like a gale?
What was the boat? A lot of weight or windage or a little thing?
What’s a “blowout”?
Reason I ask is to determine if any chain regardless of construction would fail or was this something a decent galvi chain would shrug off?

 

[Simi 60]

Reason I ask is to determine if any chain regardless of construction would fail or was this something a decent galvi chain would shrug off?

It's the characteristics of S/S
It is susceptible to crevice corrosion, all looks good until it isn't
Galv on the other hand will deform and stretch - it does not get micro cracks, appear to be ok and then fail like s/s does

But, apparently that Ketter Walden Cromox chain at around 12x the price of Galv is a different thing again.

 

[Hippocampus]

Thanks. For kicks and giggles did a commercial welding course. A great stress reliever against the cerebral work I did in my “day” job as a doc. You have to get into a particular zen frame of mind to weld SS much like Al. Otherwise you destroy its strength and properties. If you don’t use exactly the right material (and heat) to match the SS welding requirements the weld’s not SS any longer. You can weaken SS as well. Pulling a good puddle in SS is hard. I got that. I believe with chain it’s automated and not prone to human error like I did practicing. But still unlike mild steel where strength isn’t significantly degraded by a good weld I think welded SS is more prone to weakness at its welds even before issues of crevice corrosion.. I don’t know much about how SS chain is made. I know nothing about about how it’s welded. Still I would think working load and break would be stated with recognition of the SS chain’s properties and testing.
So my questions remain. Basically was this chain used in a application well past its stated working load and ultimate break? Was this chain well past its service life? What kind and brand of SS chain was involved? What were the boats properties? How much time was involved with this event? If I was anchored in a open roadstead during a 3-4 day gale I’d take a real careful look at my galvi chain and shackles afterwards.
To blanketly state SS is no good and should never be used is a big jump in my mind. Maybe this example of failure is a word to the wise. Maybe not. Without further details don’t know.
Would imagine 600’ of the stuff in the size TT would need is a pretty penny. Think he’s a wise, thoughtful individual. Don’t like the prior posts throwing stones at SS chain without further support than given.
Personally love good SS for applications above the waterline. When appropriately executed, using purging argon if necessary and polished the welds shouldn’t be an issue. Don’t like it for anchors nor rode. Think money spent elsewhere is more productive. But then expense is a concern for me and there’s always some place to spent it on a boat or entertainment while cruising.

 

[Northern Spy]

An under appreciated feature of galvanized chain is that it presents resistance to dragging through the sea bed because it's rough. SS, not so much. It kind of acts like an underwater Jordan drogue with lots of points of drag, each small, but cumulative adding up, and especially so with cross link chain. Underwater photos of ship's ground tackle seems to confirm this. Yes, when it really blows the chain lifts, but in most anchoring situations, it's the chain that is anchoring the boat.

I was the project manager for moving the breakwater hulks at the Powell River mill. It was amazing to see how many of the hulk anchors were no longer connected to the anchor chains and the and the only thing holding the ship in position was a shot or two of stud link chain embedded in the mud.

Incidentally the reason for some of the anchor detachment was that the shackle pin was worn away from galvanic corrosion due to someone mousing the shackles with SS wire. Of course this took many, many years to accomplish.

 

[twistedtree]

It's the characteristics of S/S
It is susceptible to crevice corrosion, all looks good until it isn't
Galv on the other hand will deform and stretch - it does not get micro cracks, appear to be ok and then fail like s/s does

But, apparently that Ketter Walden Cromox chain at around 12x the price of Galv is a different thing again.

As I understand crevice corrosion, it happens when SS is deprived of O2 for a prolonged time and the protective oxidation layer is lost. My thinking has been that as long as I'm not using SS chain as a permanent mooring where it's submerged all the time, crevice corrosion shouldn't be a problem. The longest the SS will ever be submerged is probably 3-5 days, and more typically 12-15hrs before it's returned to air. And over time it will probably spend 90% of it's life in air rather than water. So I'm thinking that's sufficient to maintain the oxidation later that prevents crevice corrosion?

 

[twistedtree]

It's the characteristics of S/S
It is susceptible to crevice corrosion, all looks good until it isn't
Galv on the other hand will deform and stretch - it does not get micro cracks, appear to be ok and then fail like s/s does

But, apparently that Ketter Walden Cromox chain at around 12x the price of Galv is a different thing again.

Oh, and the Cromox chain is more like 2-3x the cost of galvi. Still very expensive, but not 12x

 

[Hippocampus]

Have taken to using multiple brightly colored zip ties on shackles. The SS wire can be broken and you not know it unless you pick at it. With the plastic wire ties you know right away if the pin has loosen even the smallest bit.

 

[Delfin]

I was the project manager for moving the breakwater hulks at the Powell River mill. It was amazing to see how many of the hulk anchors were no longer connected to the anchor chains and the and the only thing holding the ship in position was a shot or two of stud link chain embedded in the mud.

Incidentally the reason for some of the anchor detachment was that the shackle pin was worn away from galvanic corrosion due to someone mousing the shackles with SS wire. Of course this took many, many years to accomplish.

I can't remember where I saw it, but I remember seeing video of tankers at anchor showing the anchor lying on its side, not dug in at all, but the vessel securely held by the chain nestled into the seabed. I think the main effect with small dude boats is a reduction in wandering around the hook.

 

[backinblue]

An under appreciated feature of galvanized chain is that it presents resistance to dragging through the sea bed because it's rough. SS, not so much. It kind of acts like an underwater Jordan drogue with lots of points of drag, each small, but cumulative adding up, and especially so with cross link chain. Underwater photos of ship's ground tackle seems to confirm this. Yes, when it really blows the chain lifts, but in most anchoring situations, it's the chain that is anchoring the boat.

While this is most likely true I don't see it as an advantage. All you are saying is that in calm conditions your anchor is not doing much to hold the boat. Who cares about holding power of chain in light conditions? I'd rather trust a well set anchor than a rough chain to hold me.

 

[Simi 60]

Oh, and the Cromox chain is more like 2-3x the cost of galvi. Still very expensive, but not 12x

I bought my last 80 metres of Australian made PWB 13mm Galv for under $2000 ( I actually paid $900 as it had water stains)

On this site 80 metres of 13 mm Cromox works out to around $21000 aud

As it is German made and that's an English supplier I would have to think it was a lot cheaper there than it would be in Australia


https://jimmygreen.com/Cromox-G6-St...-chain_size-13mm_din766/4491-length-80_metres

 

[Simi 60]

As I understand crevice corrosion, it happens when SS is deprived of O2 for a prolonged time and the protective oxidation layer is lost. My thinking has been that as long as I'm not using SS chain as a permanent mooring where it's submerged all the time, crevice corrosion shouldn't be a problem. The longest the SS will ever be submerged is probably 3-5 days, and more typically 12-15hrs before it's returned to air. And over time it will probably spend 90% of it's life in air rather than water. So I'm thinking that's sufficient to maintain the oxidation later that prevents crevice corrosion?

I have seen many chainplates on yachts with crevice corrosion and micro cracks.
Same with rigging toggles
Chainplates and toggles do not live underwater.

 

[Northern Spy]

I have seen many chainplates on yachts with crevice corrosion and micro cracks.
Same with rigging toggles
Chainplates and toggles do not live underwater.

That's likely SCC (stress corrosion cracking) , not crevice corrosion.

 

[Simi 60]

That's likely SCC (stress corrosion cracking) , not crevice corrosion.

Possibly, but still not something you want and, if I'm not mistaken, not something you'll get with Galv. Chain

 

[Hippocampus]

Yes corrosion is an issue for SS. Many flip to titanium when replacing chain plates. See troubles mainly under pins and where it pierces the deck. Also under the plate where it sits on the bulkhead if bedding has failed. All oxygen starved places and frequently wet with salt water. Don’t have the expertise of some here but it’s corrosion nevertheless.