Stainless Anchor Chain

[GordMay]

Originally Posted by Mark Johnson

SS chain is not nearly as strong, size for size, as HT-G4 galvanized...

I don’t believe that HT-G4 Galvanized chain is any stronger than Stainless G40/G43 (S40/S43) chain.
Can you provide a reference source for that statement?

[ShipShape]

Originally Posted by At sea

A major chandlery in Oz, Whitworths, includes a warning in its catalogue to the effect that stainless chain is suitable only for day anchoring, and not long term anchoring, "as it can work harden and become susceptible to cracking".

That SS is not suitable for long-term anchoring is correct, however I have not learned anything about it being due to "work hardening". Maybe they are referring to stress corrosion or corrosion fatigue.

Stainless steel "works" because of its protective oxide skin, but this skin requires oxygen to stay intact. When submerged for any length of time, you get barnacles and other organic growth on the chain, and chain on the ground can work its way into the anchoring bed. The surface of these areas of the chain are deprived of oxygen and the protective oxide layer quickly deteriorates, creating the conditions for crevice corrosion.

Additionally, pitting corrosion starts up as soon as the oxide skin is damaged - say dragging the chain over a rock. An active little galvanic cell starts at the scratch, driven by oxygen and the chloride ions in the seawater. Once these pits start there is no way to stop them, and they can get very deep very quickly. This is not a problem in fresh water.

SS chain may be fine for occasional anchoring, however for frequent/long-term anchoring, and certainly a mooring, galvanized is the correct choice.

[thinwater]

Originally Posted by GordMay

I don’t believe that HT-G4 Galvanized chain is any stronger than Stainless G40/G43 (S40/S43) chain.
Can you provide a reference source for that statement?

Oh, you can buy g43, but at $165/foot vs. $3.50/foot.... So, that would be $24,750 for something that is not better, for a 32-foot boat. It's not the money, it's that I have a brain and don't care if my chain has a few smudges. Stainless wouldn't even look right, to me.

Hilarious.

http://www.cyber-bridge-marine.com/p...ductid=AC80402

Granted, proof coil is much cheaper, but it won't fit the windlass.

[PamlicoTraveler]

Saw this in another thread on stainless anchor chains

[GordMay]

Originally Posted by PamlicoTraveler

Saw this in another thread on stainless anchor chains

From that post:
" ...the chain is 304SS the shackle is 316SS and the welds were done with 321SS ..."

I believe that all of Suncor’s S/S chain, for instance, is type 316L.
➥ http://www.suncorstainless.com/chains.html

[colemj]

Originally Posted by Bash

Acco certainly deals in stainless chain. Check here: Powered by Google Docs

I also stand by the workload of 5/16" BBB chain I published above. Check here to confirm:Acco Chain Anchor Chain

That isn't Acco's catalog, it is from ALP - a distributor. While Acco may indeed produce SS windlass chain, Acco does not list it in their catalog.

In the ALP catalog you reference, the SS chain is said to be Acco's, but they also say they supply Suncor stainless. I suspect there is an error in their catalog and they are showing Suncor chain.

You made a mistake on the galv. BBB, it is 1900lb SWL. The spec listings on WM's website are very confusing and run together.

Mark

[colemj]

Originally Posted by thinwater

Oh, you can buy g43, but at $165/foot vs. $3.50/foot.... So, that would be $24,750 for something that is not better, for a 32-foot boat. It's not the money, it's that I have a brain and don't care if my chain has a few smudges. Stainless wouldn't even look right, to me.

Hilarious.

Stainless Steel Anchor Chain Sized as G43

Granted, proof coil is much cheaper, but it won't fit the windlass.

Look closer. That is $166/10ft, not 1ft. ~$17/ft is about right for good stainless chain.

Surprisingly, 5/16" proof coil does fit a 3/8" Simpson Lawrence gypsy perfectly. It is all a matter of matching the dimensions of any chain to the gypsy.

And not arguing about the price or personal esthetic preferences, but man you should see how mud slides right off stainless as it comes out of the water. It comes on deck perfectly clean, even off the bottom of the Chesapeake.

Mark

[colemj]

Originally Posted by Mark Johnson

SS chain is not nearly as strong, size for size, as HT-G4 galvanized. A frequent application that I have seen it used in nonetheless, is on aluminum boats. The SS apparently gets along with the hull material better than galvanized chain does. Presumably one just goes up in size to match galvanized...
M.

Gotta be careful when talking about chain. There are many strength grades available. Same for galv and SS.

G50 SS (the most common high quality anchor chain) is stronger than G43 galv.

Of course, both come in higher and lower grades, so mismatched statements can be made either way.

Mark

[markpierce]

[QUOTE=Bash;596876]You'll ending up paying four times as much for stainless chain, and won't even get half the holding power.

[QUOTE]

What? I thought appearance was more important than functionality. I'm even thinking of a rode made from a gold alloy.

[thinwater]

Originally Posted by colemj

Look closer. That is $166/10ft, not 1ft. ~$17/ft is about right for good stainless chain.
Mark

Good point. I need to use my glasses.

But I'm not sure that changes my view. It's still 4x, and perhaps I like Chesapeake mud. It's traditional.

[savoir]

Originally Posted by Bash

from the Acco catalogue, stainless 5/16" 316L (S1) Stainless Chain has a working limit of 2,400 lbs. compare that with galvanized 5/16" BBB chain, which has a working limit of 7,600 lbs.

You'll ending up paying four times as much for stainless chain, and won't even get half the holding power.

Not a great investment.

You are comparing SWL of stainless with BL of BBB.

Not valid.

BL of 5/16" stainless according to Suncor is 9600 lbs.

[Wand]

Originally Posted by ShipShape

Stainless steel "works" because of its protective oxide skin, but this skin requires oxygen to stay intact. When submerged for any length of time, you get barnacles and other organic growth on the chain, and chain on the ground can work its way into the anchoring bed. The surface of these areas of the chain are deprived of oxygen and the protective oxide layer quickly deteriorates, creating the conditions for crevice corrosion.

Additionally, pitting corrosion starts up as soon as the oxide skin is damaged - say dragging the chain over a rock. An active little galvanic cell starts at the scratch, driven by oxygen and the chloride ions in the seawater. Once these pits start there is no way to stop them, and they can get very deep very quickly. This is not a problem in fresh water.

Thanks for this answer Shipshape. Just a couple of further queries...

Re para 2, wouldn't the oxygen in the water replace the 'oxide skin' on stainless chain as soon as it is scratched, rather than create a galvanic cell? I always thought that a benefit of stainless fittings was that a scratch or gouge didn't start any degradation...

Also, re para 1, how long would stainless need to be deprived of oxygen for the oxide skin to be lost? I ask that because stainless keel bolts are avoided for that reason, yet I've seen them come out in perfect condition after some years locked in timber and sikaflex.

I guess what I'm querying is whether any anchoring chain could be buried and deprived of oxygen long enough to lose the protective skin. Wind and tide should ensure that all of it 'comes up for air' regularly.

And even then, why wouldn't it immediately reskin itself (oxide layer) once exposed to the oxygen in water?

BTW, I ain't super rich - just got lucky with 40 metres of half inch stainless made in Oz for the price of galv, and want to put it to its best use.

[savoir]

Half inch stainless chain would hold a 60 footer. Maybe that's what you have.

I use stainless chain for anchoring near home. The main section of chain is 250' G4 but it comes off the boat when I'm home and 40' of stainless goes on. Works for me. The bow floats 1" higher too. Clean chain + clean anchor locker + faster boat = happy owner.

I don't know your needs or anything but I would find 40m OTT for local and too short for faraway.

[SailFastTri]

Originally Posted by PamlicoTraveler

Saw this in another thread on stainless anchor chains

I had a stainless shackle break in my hand the same way -- it was the bow shackle at the clew of the furling genoa. It was the oddest thing... I was removing the sail for the season in late fall, and as I unscrewed the pin it just came apart with a clean break. Must have been a hidden defect, but why it didn't come apart in use is a mystery to me.

[Mark Johnson]

COLEMJ,
On our 34' Searunner trimaran, minimizing weight on the bow is of paramount importance. We use a 110' section of "custom made" ACCO, galvanized 1/4", G-4 / HT chain, connected to a long section of nylon brait/plait. The "custom" aspect of the chain, is that it has a 3/8" link made into it's end by ACCO, then it is proof tested and galvanized. I had this done so that I could use a "strength compatible" connection to the anchor.

This 1/4" G-4 galvanized chain has a 2,600# SWL, according to ACCO! (Breaking strengths are irrelevant). NO SS chain, of similar size and weight to mine, even comes CLOSE to this WL. If it did, I would've used it!

SS chain does have it's down sides, but so does my G-4 galvanized, which, being hardened, is more brittle and less ductile than the standard stuff.

I like that SS chain stacks in a shorter pile, and is so much easier to clean, it is just not as strong as HT, (not pound for pound). Then there is the cost... IF SS chain last > 20 years, it might actually be about the same. I find that my galvanized chain is about shot after 5 years, and with my small 1/4" stuff, I would not consider re-galvanizing. It weakens the chain a bit, and I consider my setup to be a little marginal already.

Mark