When to replace anchor chain?

C

CalicoJack

Well-Known Member
Joined
5 Jan 2004
Messages
567
Location
Chatham, Kent
Visit site
I have just read in PBO 646 December p67, that it is recommended by Vyv Cox that anchor chain is replaced every 5 years. Now this news brought a moment of terror to me, as I have never replaced an anchor chain in my life of boating, and if this is correct with our current boat I should have already replaced it twice and be getting ready for a third time. We normally anchor a number of times over a year, maybe as many as twenty and apart from hosing the chain off when we come out of the water and inspecting it that’s the sum total of our maintenance. Our current chain is beginning to loose some of its galvanise, but it generally looks sound, although I haven’t gone over it with a magnifying glass.

Am I just a fool who has so far got away with it, or is there a misprint in this addition of PBO?
 
CalicoJack said:
I have just read in PBO 646 December p67, that it is recommended by Vyv Cox that anchor chain is replaced every 5 years. Now this news brought a moment of terror to me, as I have never replaced an anchor chain in my life of boating, and if this is correct with our current boat I should have already replaced it twice and be getting ready for a third time. We normally anchor a number of times over a year, maybe as many as twenty and apart from hosing the chain off when we come out of the water and inspecting it that’s the sum total of our maintenance. Our current chain is beginning to loose some of its galvanise, but it generally looks sound, although I haven’t gone over it with a magnifying glass.

Am I just a fool who has so far got away with it, or is there a misprint in this addition of PBO?
Click to expand...

What??? That is most definitely not what I said. I have the article in front of me and there is no mention of five years except that Dave's failed chain was less than five years old and he has heard somewhere that it should be replaced before about that age.

My current chain was bought in 2006 and was regalvanized about four years later. It remains in good condition mechanically but the galvanising is beginning to go. It is used a lot, we live aboard for half the year and often anchor twice per day. No red rust down the decks yet but it is not far off. Very little inter-link wear. I shall have no hesitation in regalvanising it again.

As with most equipment, inspection is the key. The article highlights the main points, which are wear and corrosion. The latter is sometimes user-defined: I see many boats with red-rusty chain and streaks all over the foredeck. Their owners seem happy with that but I am not.
 
My boat is mid 70's and apart from end for ending the anchor chain - its still original chain.

Just to put this in as well ...

My halyards and sheets are over 15yrs old. They get removed periodically (hopefully 1x each year) and 'washed' ... checked and put back.
My mast stays and rigging are original apart from one that suffered damage on a dock wall.
 
I'm glad that Vyv has come here and rubbished the original statement. My chain, new in about 2006, has been regalvanised twice. The last time was just a week or two ago. We're anchored for about 100 nights each year, and often several times a day, so the chain gets a lot of use. While the galvanising gradually wears away, there is absolutely no appreciable wear between the links. That is ordinary mild steel chain, and I have every confidence that it will see me out.
 
I agree with the responses so far. My chain is really old, (30 years?) has been re-galvanized about 4 times I think. I've done it twice, previous owner probably twice (like me he was in galvanizing business).
I'd say when the galv is gone, get it replaced. When the chain starts to go, get that replaced. Neither until then.
 
There are three factors that are factors in chain life (leaving out salt water) :

1. The steel thats used
2. The galvanising done
3. How the links are closed and set

Over the years 'good old fashioned' chain has been replaced with what I call 'chinese grade' ... no it does not have to come from China. It can be from anywhere. But the steel can be softer, the galvanising thinner / less resistant and the link closing not as strong as it could be.
The old days of buying certified calibrated chain are basically gone. About the only bit of certified that's left is the calibrated bit to be sure it fits your windlass. Even that I have seen some calibrated that is worse than non-calibrated.
My chain is as old as my boat - 1975 - and only the standing part (bitter end) that has only ever left chain locker when I ranged the chain is corroded. My links have literally no sign of inter link wear, galvanise is still reasonable.
But I have seen many younger boats with chain far worse than mine.
 
I'm not entirely sure of the implications but:

Chinese chain is very common now and reports of poor quality are like hens teeth. Vyv has written an article (articles (YM/PBO) and I have included Chinese chain in article(s) Practical Sailor/SAIL. Both of us have tested Chinese chain and come to similar conclusions. We have found Chinese chain, G30, to be grossly over strength and near G40 quality (so the idea it is made from poor quality steel or is badly welded, is not supported by testing). I have measured the gal thickness of Chinese chain and it is on a par with the best from N America, Peerless (America's biggest chain maker). I do not recall seeing any negative comments on Chinese chain, strength, sizing and gal life over the last 10 years or so - I don't recall prior.

The idea or the inference that 'Chinese Chain' is of poor quality is basically wrong.

Vyv and I sampled at random, or as random as possible - I bought my samples from different chandlers in Australia. You rely on the integrity of the importer and regular importers will generally buy from the same source, one they know. if you buy a cheap lot off eBay (or similar source) wonder why it is cheap and ask for an independently developed certificate of quality. Ask for 100mm of chain and conduct Vyv's galvanising test - if this is accepted and you are happy - you are good to go.

Interestingly chain failure, now, is simply not mentioned - chain seems to be strong enough and well made. The only comments of gal quality have been of specific European based chain makers - and this is despite the fact most chain, at least in the UK, comes from China.

Longer term - things might change. I advocate that the relevant magazines schedule chain checks regularly, every 5 years?, so that quality can be monitored (and I'd add shackles to the list) - but whether they can be persuaded to fund the testing - different question. But if you do not buy the magazines, PBO, YM, Practical Sailor, SAIL and rely on forum like this for your information then the likes of Vyv and I are unable to extend largesse to fund the testing ourselves. There are lots of opinions on ground tackle - often without any technical basis (gut feel and xenophobia are often the foundation) - if you want data based on testing ??? - maybe something to think about.

Jonathan
 
The best Chinese chain, as Jonathan says, is of excellent quality. The then-director of Bradney chain told me some years ago that their supplier made the best in the world, made on new German-made machines and at the time manned by German technicians. The steel they use has a higher carbon and manganese content than is required by the specification, hence its better mechanical properties. The reason that calibrated chain is no longer available is that it is no longer needed - all chain is produced with high accuracy to the relevant specification, unlike the past when different facilities produced chain to different sizes that then had to be 'adjusted' to fit each maker's windlass gypsy.

In UK it is easy to ensure that the chain being bought is from the best Chinese sources (as with most things in life there is bad as well as good) - buy from the big importers such as William Hackett, Bainbridge and Rigmasters. They test imported chain regularly and will usually provide a copy of the certificate.

Unfortunately galvanising quality meets the specification minimum, which for marine chain is insufficient. Poor galvanising life is problematic across the industry regardless of country of origin, although Chinese does seem to last better than French and Italian. However, as this thread shows, the zinc on hot dip regalvanised chain only has a life of around 10 years on frequently used anchor gear. Interestingly my chain has never been end-for-ended but has corroded almost equally at each end, whereas the centre part is not so bad.
 
Where corrosion is most likely to become an issue before it's obvious is if you have a mixed rode and a rope-chain splice. The rope woven through the links keeps the chain nice and wet with salty water, multiplying the rate of corrosion, but an annual inspection will tell you when it's time to sacrifice those few inches of chain and remake the splice. I think I've done it twice in 15 years of boat ownership.
 
Galvanising is harder and thus more abrasion resistant than the underlying mild steel for most commonly used anchor chain, G30 and G40 or G43. The hardness of galvanising is a bit better than American G70 and about the same as Maggi G70 (which I suspect is based on a G100 stock). There are galvanising methods other than Hot Dipped Galvanising (HDG) one being Thermal Diffusion Galvanising (TDG) - this is what I have used (trade name Armorgalv) and it offers an even harder coating (than HDG) with a precisely known coating thickness and no exterior soft zinc

However the outer layer of galvanised (HDG) chain is usually raw zinc and it is soft and wears off quickly. When you see your chain rusting and it may rust at the crowns or the long of the link first - depending on how you use it (the seabed in which you anchor) then you will start to wear the base steel (and its the base steel that gives the chain strength). Once you have worn the base steel by 10% in needs to be retired. The trick it to catch the chain when it starts to show signs of rust - and have it regalvanised. So measure the long of the link and the crowns - ideally you want some of your unused chain against which to compare......

Reports are that chain that has been regalvanised has a longer galvanising life than original chain. This is a consistent comment - but I don't know why regalvanising is better than original galvanising.

As Vyv mentions the specification for the thickness of galvanising (HDG) is 'crude' or 'simple' and does not tell you the 'quality' of the coating and you cannot measure the coating thickness anyway (unless you have a coating thickness meter, or borrow mine). But Vyv has a very simple test for coating adhesion - look at his website. Some European chain, from Italy, has failed Vyv's test miserably (but my last use of Vyv;s test on Italian chain was a few years ago - hopefully things have improved. The horror stories on Italian chain were of chain bought a good few years ago, the Italian chain maker went into administration hopefully they have their act together now.

Theoretically the coating could be largely soft zinc or hard alloy layers - even if you know the thickness you don't know what the coating is based on (alloy or zinc). I have a simple abrasion test - but that's not much use to anyone in the UK buying chain (I simply hang lengths of chain, 200mm, from a long rod and allow them to drag on the seabed - but you need to develop a standard with which to compare - or you need samples of each chain you might want to buy. You need a decent weighing balance - as that is the quickest way to see wear).

It is impossible to know how long galvanising will last- It depends on how much you anchor, what the seabed is like (mud or sand and type of sand) and how you look after your chain. If you anchor is some mud the mud itself, or the organisms in the mud will dissolve the gal (any gal as they produce directly or indirectly sulphuric acid (the bad egg smell) and you chain will go black).

If you want to extend the life of your chain wash it as often as you can with fresh water, never leave it sitting in a puddle of salt water, wash off the mud, let the chain dry and keep any rope away from the chain (see another post above about the splice allowing the chain at the splice to corrode).

If you use your chain a lot - you are a live aboard then you will not necessarily see the chain rusting - as every time you use it you will wear the rust off - but if you look carefully you will see the base, shiny, steel - which does look different to galvanising.

https://www.sailmagazine.com/diy/know-how-ground-tackle

Jonathan
 
Last edited:
"Wash as often as you can with fresh water".
That's not so easy for those of us who are either anchored or sometimes on a mooring. Fine for marina based boats, but then they don't anchor as much. We carry quite a lot of fresh water, but I'm not going to squander it on the chain, so it'll just have to make do with salt water. :D
 
AndrewB said:
Does anyone know where to get a chain regalvanised in Greece - in easy reach of Corfu for preference?
Click to expand...

I don't know exactly but there are galvanisers in Athens. Any boatyard can arrange it, I have seen a couple of pallets of regalvanised chain on my travels. I recall that noelex had his done a few years ago when hauled out in Leros. All i have seen were batch process, i.e. not a dedicated chain line as with BE Wedge at Willenhall.
 
NormanS said:
"Wash as often as you can with fresh water".
That's not so easy for those of us who are either anchored or sometimes on a mooring. Fine for marina based boats, but then they don't anchor as much. We carry quite a lot of fresh water, but I'm not going to squander it on the chain, so it'll just have to make do with salt water. :D
Click to expand...

But you do go and get fuel and unless you refuel, as we do, with 20l drums most fuel wharfs have fresh water. I also vaguely recall that Scotland is well endowed with rain water - leave the hatch of the chain locker open and wash it with no effort from yourself.

If you use your chain frequently then seawater is fine - but people who anchor only occasionally and keep their yachts in marina may retrieve and forget - they will wash the deck - when they get back to their berth - but never think of putting the hose into the chain locker - they then leave the chain festering for a few weeks covered in salt and worse mud.

Once you have washed the chain - leave the hatch of the locker slightly ajar - to try to have the chain dry out.

Jonathan
 
vyv_cox said:
I recall that noelex had his done a few years ago when hauled out in Leros. .
Click to expand...

You have a good memory Vyv :). The Leros boatyard arranged for our anchor to be re-galvanised (we replaced rather than re-galvanised the chain at the same time).

The boatyard sent the anchor (a Rocna 55) away to a company near Athens, but unfortunately I don’t recall the name. Interestingly, when it came back the galvanising on the fluke was very different in appearance to the shank. The difference was presumably resulting from the different steels used for the construction.

Anyway, the re-galvanising held up well, better than the original (New Zealand made) Rocna galvanising. I wish we could say the same about the new G7 chain that had a short life, but we are very tough on anchoring gear. The anchor only receives a freshwater rinse every two years, when we haul out for fresh antifouling. The rest of the time the anchor is either on the seabed holding the boat or on the bow while we are sailing between anchorages. That is just the reality when full time cruising and spending most of the time at anchor.
 
noelex said:
Interestingly, when it came back the galvanising on the fluke was very different in appearance to the shank. The difference was presumably resulting from the different steels used for the construction.

Anyway, the re-galvanising held up well, I wish we could say the same about the new G7 chain that had a short life, /QUOTE]

The difference in appearance for the re-galvanised Rocna was one of the reasons behind the Rocna bendy shanks. When the anchors were galvanised in Shanghai, with a coal fired galvanising bath, the anchors came out with a variegated grey finish. The flukes were cast, the roll bar mild steel and the shanks a high tensile steel (they may have been using Biasalloy's Bisplate 80). Without thinking it through they changed the shanks to a mild steel - I think this resulted in a more even grey of the anchor but had other consequences. Most anchor makers when they find different hues of grey, or silver, simply spray paint with an aluminium pigmented paint.

If you have a Rocna, or an anchor where the steels used are different, it is now common to use a higher tensile shank, then if you have it re-galvanised do not be surprised if the shank and fluke are a different colour of grey or silver. As Noelex remarks its a function of the steel chemistries.

The mention that regalvanising is better then the old original galvanising is a continual and consistent comment.

The comment that the Italian G70 chain had poor galvanising has nothing, as such, to do with G70 - the same comments of poor gal life have been made for the same company's G40. It appears to be a galvanising issue - nothing, or little, to do with the base steel. Tests also show that chain size has little nothing to with gal life either. A small chain will not noticeably lose gal any more quickly than a slight larger chain, so 6mm and 8mm will have a similar life. 6mm may have a different life to 12mm (the 6mm might be better) - but that is unlikely to be the comparison

Galvanising of chain is a bit of a lottery - and though the manufacturers might have a specification - it is not mentioned to the buying public. Given that the galvanising determines chain life - this omission is surprising. Maybe if we made more noise of its absence - things might change. The only easy tests of quality is Vyv's twist link test, see his website (do it - and report your findings here - if you don't do it - don't be so surprised to find you bought a lemon).

So who has bought chain in the recent past - what results did you achieve - or can you cut a link of the bitter end (as you should not yet have end for ended it) - and report back - defining source.

Jonathan
Click to expand...
 
Last edited:
Neeves said:
...The only easy tests of quality is Vyv's twist link test, see his website (do it - and report your findings here - if you don't do it - don't be so surprised to find you bought a lemon).

Jonathan
Click to expand...

Many years ago I worked in the lab of a company making industrial cladding. The base metal was galvanised sheet, about 18 gauge. Our approval test, which I believe was in the British Standard at the time, was to bend the steel 180 degrees in a vice. If any galvanising came off the steel was rejected. Easier for thin sheet than the wire of a chain but still a good guide. I have found quite a few 8 mm links that did survive the twist and quite a few that did not.
 
NormanS said:
"Wash as often as you can with fresh water".
That's not so easy for those of us who are either anchored or sometimes on a mooring. Fine for marina based boats, but then they don't anchor as much. We carry quite a lot of fresh water, but I'm not going to squander it on the chain, so it'll just have to make do with salt water. :D
Click to expand...


When on a swinging mooring, I used to lash the locker open when heavy rain was forecast - not an unusual event in Plymouth. -)
 
You must log in or register to reply here.

Share this page

Top