Thoughts on Stainless Steel Anchor Chain?

[Simi 60]

Originally Posted by Adelie

So you suggest creating a very large hole in the hull in a locations likely to see lots of water running across the deck and the occasional wave crashing down on the cover?

Its what we have with a 2 inch lip and a hatch covering hole
Hole large enough to a big bloke to drop through
And 6ft + headroom and space to work when in there.

But, our deck is close to 10ft off the water

Saying that, plenty of smaller boats have an anchor locker with a lid
My first 23ft keel boat did
My 33ft sailing cat did.

[Jim Cate]

Originally Posted by arthur.watson.1

I have a question—two, actually.

First, the OP stated that his problem was the chain piling up until it got in the way of the bottom end of what we came to learn was the “spurling pipe.” My question is, why do we need a spurling pipe? I do not have one on my boat, and my chain simply falls vertically into a heap. When the heap gets too tall or too steep, the chain simply slides off to one side or other and keeps piling up. This system works fine for me. If the chain is piling up to the bottom of the pipe, perhaps the OP could add more usable height to his locker by shortening or eliminating the pipe.

Second, while we're on the subject, has anyone tried installing a pipe or hose that guides the chain down and aft into a deeper (and possibly larger) space, for example under the V berth? More space, weight lower and further aft.

If anyone has tried this and had a good outcome, I would be interested hearing more about their experience.

Arthur, the term "spurling pipe" refers to any aperture in the deck through which the chain descends into the chain locker. It may or may not have a length of actual pipe to direct the chain, but in most yacht installations it is simply part of the windlass structure and does not extend much below the deck level.

Jim

[joelhemington]

Originally Posted by Departing2017

Ok, so once you've stopped laughing and rolling your eyes at my vanity and extravagance (probably justified, if you ask the Admiral), I have a couple of serious questions.


I have been exploring the option of upgrading to stainless anchor chain, and here's why. We do not have access to our chain locker from the deck, and our current chain (3/8" galvanized G4) makes a nice cone-shaped pile in the locker that fouls the hawse pipe long before we have the anchor up. This necessitates placing a crew member below in the V-berth to reach through a small opening in the bulkhead and manually stack the chain. Problem is, we're usually short handed and don't have a crew member to spare.


My understanding is that stainless chain being a bit more slippery won't pile itself into a cone. So first questions: Is this true? And do you think SS chain would solve my problem as described?


Next question. As I'm researching online, I'm running into huge variation on the price of SS chain. Around $2,700 for 300 feet on the low end up to almost $9,000. Nine grand is a non-starter, but the bottom end of the range might be worth it. I'm guessing the price difference boils down to Made in China versus Made in Not China. The sources for the lower priced chain at least appear to be fairly reputable marine retailers. How much do I worry about quality control on SS chain if it is made in China?


Thanks for sharing any thoughts.

I'm curious, having lived on Oahu for twenty years and sailed around the whole island at least a couple of times, where exactly do you anchor? Waikiki has a pretty good sand bottom but it's about a 60' drop (so lots of scope needed) Every where else is pretty much surrounded by reef and drops off radically deep once you get out far enough to avoid washing up on the reef. Sunset Beach in the summer is very calm but the bottom there is all rock as the winter swell tosses all the sand back up on the beach. Hanalei Bay on Kauai is the only place I recall seeing people anchor and that could be a three day sail from Oahu.

[Fbfisher]

I thought a soccer ball or similar was a solution to this?

[Alan Mighty]

Originally Posted by Jim Cate

Arthur, the term "spurling pipe" refers to any aperture in the deck through which the chain descends into the chain locker. It may or may not have a length of actual pipe to direct the chain, but in most yacht installations it is simply part of the windlass structure and does not extend much below the deck level.

This use of "spurling" is probably only 100 years old (meaning 1920s). Really.

Started with the term "spurling gate", the name for a metal rimmed hole in the deck through which anchor cable could flow to and from the chain locker.

About 10 years later (meaning 1930s) "spurling gate pipe" then "spurlingate pipe" and finally about 60 years ago (really!) "spurling pipe".

Although it's not been around in text for a while "spurling gate" would be a useful term.

The pipe, if it exists on a vessel, could just as well be called "chain pipe", "spill pipe", or "navel pipe". Any of them is more likely to fit into landlubber's vocab than "spurling" or even "spruling".

"Spill pipe" is neat. Let me come back to that one ...

We have two sets of earlier references to "spurling".

First is about 200 years ago (1820s). Then the word was in the term "spurling line". A spurling line could be any of a few things, including: the cordage that connected the steering system to a tell-tale showing the angle of the rudder; and a line spliced with several thimbles or grommets, each acting as a fairlead for running lines.

The second was just less than 70 years ago. The editors of Encyclopedia of Nautical Knowledge (1953) surveyed the archives and argued that spurling was formerly an ‘English word for flowing, running, or turning, as a rope in a block’.

That ENK statement has not been disputed. And no one has bothered to support it (or even examine it further). A PhD dissertation waiting to be funded and written, for sure.

The ENK statement fits. Chain flows through the spurling gate into and out of the chain locker. Note well that English "gate" has two sources: one the gateway; the other the thing that can temporarily block the gateway.

Similarly, a spurling line turns around a shaft connected to a steering quadrant with a tell-tale moving within sight of the helm so the helmsman knows the rudder angle. Or a spurling line acts to hold fairleads through which other lines flow or run.

Spill pipe picks up that idea of chain flowing or running like a fluid. Chain pipe is simple and direct.

Navel pipe (sometimes written as 'naval pipe') relates the spurling gate to the omphalos of a placental mammal (navel and omphalos and umbilicus are Germanic, Greek, and Latin versions of some original - likely proto Indo-European - word).

[Departing2017]

Originally Posted by Gaia

We were faced with that problem on our shallow draft Gazelle. Without enough drop the chain would pile up like you describe. We solved the problem by dropping the chain on a sloping platform equipped with a trap door equipped with bungee cords. The chain flows over the trap door into the aft part of the chain locker until that is filled and then it piles up on the trap door further forward opening it. Works for us.

Jim sv Gaia

That is a cool idea. I'll be experimenting. Thanks.

[Departing2017]

Originally Posted by joelhemington

I'm curious, having lived on Oahu for twenty years and sailed around the whole island at least a couple of times, where exactly do you anchor? Waikiki has a pretty good sand bottom but it's about a 60' drop (so lots of scope needed) Every where else is pretty much surrounded by reef and drops off radically deep once you get out far enough to avoid washing up on the reef. Sunset Beach in the summer is very calm but the bottom there is all rock as the winter swell tosses all the sand back up on the beach. Hanalei Bay on Kauai is the only place I recall seeing people anchor and that could be a three day sail from Oahu.

We're in Oahu temporarily. We've been cruising full-time for about three years, and came up here from French Poly to wait out the craziness. We're currently "chained" to the dock replacing all chainplates, so not much anchoring going on right now. But normally we're on the hook most of the time.

[Departing2017]

Once again, the forum proves its worth. Thanks everyone for the great info. Given the eye-opening info on corrosion issues and the great suggestions for less extreme ways to solve my problem, I think I'll look for other things to waste my money on.

The nine-year-old is coming into his own as the ship's official chain stacker, and I think we'll stick with that crew arrangement for now. He's not going to like it, but if the professional video game player gig doesn't pan out, he'll always have chain stacking to fall back on.

[Alan Mighty]

Originally Posted by Departing2017

Once again, the forum proves its worth. Thanks everyone for the great info. Given the eye-opening info on corrosion issues and the great suggestions for less extreme ways to solve my problem, I think I'll look for other things to waste my money on.

Excellent choice, D2017.

I tried to design my questionnaire so that those choosing (a) at each question were suitable customers for stainless steel anchor chain. While those who chose (b) were better staying with galvanized steel.

The boat in the next marina berth to me is a good example. He (let's call him R) has a 30-something foot runabout, called a 'bowrunner'. It's a sort of party boat thing. Rumoured to sometimes have skimpily-clad people on board (an unfounded rumour, Mrs R).

R drives out of the marina, anchors in coastal aerated water over clean quartz sand. Has a cold beer, chars some mammal flesh on the BBQ, then runs back to the marina.

The anchor and chain come up clean. Look superb - genuine boat jewelry. Chain stows neatly in the locker.

R uses 316 austenitic stainless steel chain, an austenitic stainless steel shackle, and an austenitic stainless steel anchor. Washes it down with dock water back at the marina.

The clean quartz sand presents little galvanic risk to the stainless steel. The short dunking, followed by a freshwater wash, minimises a lot of the corrosion risk. The anchoring and the stowage present little risk of low oxygen levels.

Cruisers know that 316 austenitic ss is a compromise and a compromised material.

For a cruiser, the duplex stainless steel chains and shackles (2205 or 318LN) are much less of a compromise. Jolly expensive (~US$15 a foot for 8 mm 5/16" short link) to buy. And only worth buying if tested and certified. And then either inspected. tested, and re-certified or replaced.

As Simi 60 and others have mentioned, Cromox Suprene 40 at Euro 60/metre for 8 mm 5/16" short link, made of 2507 super-duplex stainless steel is the one to get.

I've followed Jim Cate and others in replacing 316 austenitic chainplates and chainplate bolts with 2205 duplex and/or 2507 super-duplex ss.

Galvanized steel ground tackle, likely to bend or stretch before it breaks, remains my choice, even though I have embraced duplex and super-duplex to anchor the rig to the hull.

Jim Cate has proven duplex ss chainplates for 25+ years of service. No one has yet proven super-duplex anchor chains for that duration.

[carstenb]

Originally Posted by Simi 60

Amazing these stories of chain and galv longevity.

Ours shows signs of rust within 6 mths and is generally rusty over the used length within 12 mths.
The first lot was an unknown breed, but was near new when we got the boat.
Showing sign of rust within 6 mths and replaced at 2 years due to stretching slightly from a storm and not going nicely through chainwheel.

Second lot using Australian made PWB and it was rusting within 6 mths
Daily use dragging through sand and mud has it come up shiny, but within hours that rust colour is on it.
About to chop out the first 30m as it doesnt run through the chainwheel nice anymore either.

Our experience is similar to this. Galv chain that had lost all the galv after a couple of years of anchoring. We turned the chain after about 1 year, but replaced it after two (we live on teh hook so it was constantly in the water)

Wouldn't have stainless - fellow on a cat showed me his stainless that parted due to crevice corrosion - happily he was on board so no damage to the boat.

I sometimes worry about my stainless shackle and my stainless swivel - does anyone have any ideas about how much I should lie sleepless at night?

[Simi 60]

Originally Posted by carstenb

)

Wouldn't have stainless - fellow on a cat showed me his stainless that parted due to crevice corrosion - happily he was on board so no damage to the boat.

But apparently there is stainless and then there is "magic cromox" stainless.

I sometimes worry about my stainless shackle and my stainless swivel - does anyone have any ideas about how much I should lie sleepless at night?

Why would you would be the question.
If you don't trust stainless chain why would you trust other stainless components when far cheaper, sleep at night alternatives are available?

[Alan Mighty]

Originally Posted by Simi 60

But apparently there is stainless and then there is "magic cromox" stainless.

Ketten Walder and their cromox brand, do not have a monopoly on duplex ss (dss) or super-duplex ss (sdss). You can buy sheet and plate dss at your local steel supplier, such as Stirlings at Cooper Plains.

The magic that Kettten Walder performs is making anchor chain out of dss (318LN or 2205 dss) and sdss (2507). And then testing, certifying, and (with the top grades) electropolishing. Then Ketten Walder stands behind their brand and gives a 3 year warranty. Further, if you carry your anchor chain back to Ketten Walder just before their 3-year warranty expires, they'll inspect, test, re-certify and re-polish the anchor chain. For Euro60/metre for the only sdss chain in town, why not?!

DSS is called duplex because it is not just austenite crystals (316 is an austenitic ss) but a solution of both austenite crystals and ferrite/martensite crystals. And there's a big mob of magic in that solution.

DSS has been around for 90 years now (I think 2020 was probably the 90th birthday, but it took a while to be appreciated.

DSS was invented a couple three times, just but increasing the proportion of chromium in the melt. At least once it was by accident. That was in about '35, when a factory was making a standard austenite ss by the formula and blundered because one bloke tipped too much chromium into the melt. That resulted in a demerit for the worker who'd 'wasted' the precious chromium powder, but the foundry got a patent for the result! I don't remember if the first foundry making dss (Avesta of Sweden making 453 dss) held a patent for dss (I've always found Swedish patents difficult to research - feel free to interrupt if you're good at Sverige patents from the 1930s to 1960s).

Ketten Walder prefers to spec their dss as 318LN. I prefer calling dss and sdss by the SAF designations: 318LN is 2205; and one grade of sdss is 2507. So the first one is about 22% Cr (by weight) and 5% Ni, with of course 3% Mo (so 2205). 2507 is 25% Cr, 7% Ni, and 4% Mo.

Contrast that with 316 - about 16% Cr, 10% Ni, and (depending who is making it) 2 or 3% Mo. Pushing the Mo proportion above 3% makes a big difference in resistance to pitting corrosion.

We all care about the same three or four things with ss: yield strength, stress cracking corrosion, pitting corrosion. And those are inter-related.

Look at YS.jpg. 2205 has double the yield strength of 316. 2507 even better than double.

For resistance to stress cracking corrosion, look at SCC.jpg. Resistance to SCC is rated in percentage of Yield Strength (so you can see the interrelationship just mentioned), so you get a multiple effect if you replace 316 with dss or sdss: one YS increases by two-fold or more; and then the percentage of YS at which SCC rears its ugly face rises.

For resistance to pitting corrosion and crevice corrosion look at the curves of Critical Pitting Temperature and Critical Crevice Temperature in CPT CCT.jpg. You can see why 316L anchor chain can be used in cool waters, as noted by Muaddib1116 upthread. 2205 does better. But with the oceans at the end of the beginning phase of climate change (and getting hotter) you can see why anyone who depends on shiny anchor chain needs cromox Suprene made from 2507! 2205 is not good enough to stop crevice corrosion in waters up to 30C. In late summer 2020 the waters around Japan and northern Taiwan were cooking. Right now the waters just off a section of the N coast of PNG are cooking.

[skipmac]

Originally Posted by Jim Cate

Worthless trivia correction: it is a spurling pipe, not a spruling pipe.

Jim

More worthless marine trivia. The phenomenon of chain piling up in the locker when retrieving it is called castling.

[NSboatman]

Originally Posted by Departing2017

I love worthless nautical trivia. Worthless trivia of any kind is pretty much the only thing I can consistently remember. Thanks!



The other problem I didn't mention is that even if the spruling pipe doesn't get fouled, that nice cone-shaped pile of chain will ultimately fall over and create a tangle that will not feed next time we drop anchor, so I don't think trimming the pipe will help.

I think technically it is a “spurling pipe”, not a spruling pipe... sp?

...doh. I see others have already corrected. Sorry!

[Muaddib1116]

Originally Posted by Alan Mighty

Ketten Walder and their cromox brand, do not have a monopoly on duplex ss (dss) or super-duplex ss (sdss). You can buy sheet and plate dss at your local steel supplier, such as Stirlings at Cooper Plains.

The magic that Kettten Walder performs is making anchor chain out of dss (318LN or 2205 dss) and sdss (2507). And then testing, certifying, and (with the top grades) electropolishing. Then Ketten Walder stands behind their brand and gives a 3 year warranty. Further, if you carry your anchor chain back to Ketten Walder just before their 3-year warranty expires, they'll inspect, test, re-certify and re-polish the anchor chain. For Euro60/metre for the only sdss chain in town, why not?!

DSS is called duplex because it is not just austenite crystals (316 is an austenitic ss) but a solution of both austenite crystals and ferrite/martensite crystals. And there's a big mob of magic in that solution.

DSS has been around for 90 years now (I think 2020 was probably the 90th birthday, but it took a while to be appreciated.

DSS was invented a couple three times, just but increasing the proportion of chromium in the melt. At least once it was by accident. That was in about '35, when a factory was making a standard austenite ss by the formula and blundered because one bloke tipped too much chromium into the melt. That resulted in a demerit for the worker who'd 'wasted' the precious chromium powder, but the foundry got a patent for the result! I don't remember if the first foundry making dss (Avesta of Sweden making 453 dss) held a patent for dss (I've always found Swedish patents difficult to research - feel free to interrupt if you're good at Sverige patents from the 1930s to 1960s).

Ketten Walder prefers to spec their dss as 318LN. I prefer calling dss and sdss by the SAF designations: 318LN is 2205; and one grade of sdss is 2507. So the first one is about 22% Cr (by weight) and 5% Ni, with of course 3% Mo (so 2205). 2507 is 25% Cr, 7% Ni, and 4% Mo.

Contrast that with 316 - about 16% Cr, 10% Ni, and (depending who is making it) 2 or 3% Mo. Pushing the Mo proportion above 3% makes a big difference in resistance to pitting corrosion.

We all care about the same three or four things with ss: yield strength, stress cracking corrosion, pitting corrosion. And those are inter-related.

Look at YS.jpg. 2205 has double the yield strength of 316. 2507 even better than double.

For resistance to stress cracking corrosion, look at SCC.jpg. Resistance to SCC is rated in percentage of Yield Strength (so you can see the interrelationship just mentioned), so you get a multiple effect if you replace 316 with dss or sdss: one YS increases by two-fold or more; and then the percentage of YS at which SCC rears its ugly face rises.

For resistance to pitting corrosion and crevice corrosion look at the curves of Critical Pitting Temperature and Critical Crevice Temperature in CPT CCT.jpg. You can see why 316L anchor chain can be used in cool waters, as noted by Muaddib1116 upthread. 2205 does better. But with the oceans at the end of the beginning phase of climate change (and getting hotter) you can see why anyone who depends on shiny anchor chain needs cromox Suprene made from 2507! 2205 is not good enough to stop crevice corrosion in waters up to 30C. In late summer 2020 the waters around Japan and northern Taiwan were cooking. Right now the waters just off a section of the N coast of PNG are cooking.

That's some great info, thanks!

My boat came with Ketten Walder 10mm 318LN chain that was bought in 2016 by a previous owner. I haven't done a full inspection of it yet, but the section next to the anchor looks like it's in great condition. I don't think it's actually gotten that much use until recently when the most recent owner was quarantined in Antigua for a couple months in the spring. Prior to that the boat was used rarely in the Med, probably spending most of the time at dock. My plans are to use the boat in New England and Canada for the next couple years, before venturing south to warmer waters, so I'm pretty confident in the chain right now. I'll have to make a decision then whether or not I'm comfortable to keep using it. As far as replacing it, Ketten Walder only has Super Duplex in 8mm, so unless that changes (and assuming I'm willing to pay the premium) I'll go to galvanized chain.

As far as what to call it, for Duplex, I've seen 318LN, 2205, and AISI318LN and for Super Duplex 2507 and AISIF255, but like you've alluded to, I've also seen there are a number of Super Duplex alloys aside from 2507.

Interestingly, from what I've been able to figure out from Ketten Walder's catalog and 1stchainsupply's strength chart, the breaking strength of Ketten Walder's 318LN 10mm chain is a good deal higher than 3/8" G43 chain and a little lower than 3/8" G70 chain. But more interestingly, they claim a SWL of half the Breaking Strength, whereas it seems like for galvanized chain the SWL is 25% of the Breaking Strength for G70 and 33% for G43. I don't yet have a good idea of what this means, practically.