Anchor chain 8mm or 10mm

[Pinnacle]

I am truly loath to start another anchoring thread but my simple proposition is as follows:
Intend replacing the 21kg plough and chain on 1999 Bav 42, 43.5’ish LOA and 8.5 ton displacement with Rocna mk1 25kg and 60 m G40 8mm and 30 metre octoplait.
Bav say German Lloyds say 8mm good for this size of boat; Jimmy Green tables say need 10mm.
What size would you go with? (oh and what diameter rope to splice on?)

All 10mm and no rope is my vote.

 

[Malish]

I am truly loath to start another anchoring thread but my simple proposition is as follows:
Intend replacing the 21kg plough and chain on 1999 Bav 42, 43.5’ish LOA and 8.5 ton displacement with Rocna mk1 25kg and 60 m G40 8mm and 30 metre octoplait.
Bav say German Lloyds say 8mm good for this size of boat; Jimmy Green tables say need 10mm.
What size would you go with? (oh and what diameter rope to splice on?)

If you are pricing up then do get a quote from Retail online mooring equipment - Chain, ropes, buoys, sinkers, anchors - UK Delivery. the quality is good and the price much better than many.

Previous thread here Seago Anchor Chain?

 

[MapisM]

Intend replacing the 21kg plough and chain on 1999 Bav 42

Just curious, is the existing anchor and chain rotting away?
Because other than that, it sounds more than good enough for anything but really extreme anchoring conditions.

Anyhow, just to throw in another answer to your OP question, mine is 8mm all chain.
I hate ropes with a passion!

 

[Sea Change]

I assume you’ve done the calculations to compare stainless chain with galvanised. How many years would the stainless chain have to last to make it comparable (on a cost basis) with galvanised chain I wonder?

I occasionally fantasise about switching to stainless. Just think of it tumbling down all by itself in the locker like a shiny liquid. And the almost infinite lifespan, in theory.

But then you price it up and it's at least five times the price of galvanised. It's reasonable to expect a galvanised chain to last 3-5yrs of continuous use. So the payback time on stainless is going to be 15-25yrs. That makes it pretty hard to justify when there are other things to spend money on.

 

[Neeves]

All 10mm and no rope is my vote.

The difference between 8mm and 10mm is is a bit less than 85kg if you plan on 100m - do you really want to have the weight of a man standing on the bow as you bash to windward. On a 20t yacht its nothing - on the OPs yacht it is significant.

Jonathan

 

[Neeves]

Just curious, is the existing anchor and chain rotting away?
Because other than that, it sounds more than good enough for anything but really extreme anchoring conditions.

Anyhow, just to throw in another answer to your OP question, mine is 8mm all chain.
I hate ropes with a passion!

In this context rope is useful as a snubber. Maybe research the idea! .

Jonathan

 

[geem]

Frankly the difference in galvanising rate loss between 8mm or 10mm chain is 'nothing'. If it were years different it would be important but its probably dictated by the quality of the galvanising not the chain size and the day of the week it was galvanised..

If you swap your gypsy from 10mm to 8mm it would be prudent to keep the 10mm gypsy anyway - its not as if its a great weight.

Interestingly Starzinger and Dashew both thought down sizing had merit and Dashew's yachts were around 40,000kgs, Hawk I recall was around 14t`and 47' aluminium Van De Stadt.

But its only a difference of 85kg on your yacht, 100m of either 8mm or 10mm - it does not even merit a discussion

Jonathan

We only carry 60m of chain so even less difference so really not worth the effort or cost of going to G70 8mm.
I just had my existing 10mm chain regalvanised here in the UK before we head off again shortly. Spin galvanising, so it will be interesting to see how long it lasts before we renew it

 

[geem]

Interesting, how many nights at anchor over the three years? I see that 80m of G70 8mm is £1400 from JGM, so if you’re at anchor for 1,100 nights (3 years) that’s about £1.25/nt. I reckon that’s reasonable, we have to accept that most things on board are consumables, nothing lasts forever.

Almost all nights at anchor except 6 weeks in a marina at the beginning.
Our chain is G45. 60 metres of 10mm. It costs us €450 last time we purchased it in Martinique. That was just over 3 years ago. We have had it regalvanised at 2 years old. We have been in dry dock for the last 11 months.

 

[noelex]

There is no doubt that switching from larger G40 to thinner G70 chain results in a significantly shorter chain life. This has been our experience (using the two chain types in identical anchorages on the same boat) and other boats we have talked to who have made the change. Interestingly, in a YouTube video posted a few days ago documented the same experience. See the link below (at about the 7 minute mark).

This is a screenshot on how their thinner G70 chain looked after only 18 months of use.



It is simply one of the drawbacks of making the switch, not much of a problem if you anchor infrequently, but for people full-time cruising, it is expensive and a pain to change chain as frequently as every year and a half.

I am not sure if this is related to the greater difficulty galvanising heat-treated alloy steel as mentioned by Vyv in post #8. Or if it is related to greater movement of the thinner chain on the seabed, or perhaps a combination of factors.

BTW, don’t listen to those that suggest light chain will spend most of time above the seabed; just dive and take a look. Even very light chain will only be all off the bottom a very small amount of the time (during strong wind). The most galvanising wear is invariably where the chain starts to touch the seabed. Unfortunately, lighter chain rolls around the seabed more than heavier chain (on the same sized boat) and it hard to image this extra abrasion does not factor into the life of galvanised chain.

 

[geem]

There is no doubt that switching from larger G40 to thinner G70 chain results in a significantly shorter chain life. This has been our experience (using the two chain types in identical anchorages on the same boat) and other boats we have talked to who have made the switch. Interestingly, in a YouTube video posted a few days ago documented the same experience.see the link below (at about the 7 minute mark).

This is a screenshot on how their thinner G70 chain looked after only 18 months use.

View attachment 195874

It is simply one of the drawbacks of making the switch, not much of a drawback if you anchor infrequently, but for people full-time cruising, it is expensive and a pain to change chain as frequently as every year and a half.

I am not sure if this is related to the greater difficulty galvanising heat-treated alloy steel as mentioned by Viv in post #8. Or if it is related to greater movement of the thinner chain on the seabed, or perhaps a combination of factors.

BTW, don’t listen to those that suggest light chain will spend most of time above the seabed; just dive and take a look. Even very light chain will only be all off the bottom a very small amount of the time. The most galvanising wear is invariably where the chain starts to touch the seabed. Unfortunately, lighter chain rolls around the seabed more than heavier chain (on the same sized boat) and it hard to image this extra abrasion does not factor into the life of galvanised chain.

Thanks for confirming my thoughts.

 

[Neeves]

Anecdotal comment and Video rules


Yet galvanised G7 or G70 has been available and is part of the portfolio of quality chain makers and distributors.

Now... we didn't buy an off the shelf G7 anchor rode, we 'made' our own.

Is Jimmy Green mad, is Peerless (America's biggest chain maker) selling an unrealistic dream.


Jonathan

 

[Neeves]

Most people will not go to the trouble of buying none galvanised chain and having it Sherardised for an extra unknown life expectancy. These just want off the shelf chain at reasonable cost.
These factors are why we buy G45 10mm chain in the Caribbean at reasonable cost and we don't drop to G70 8mm chain at considerable cost. We would be scrapping it in 4 years

This is still PBO?

Jonathan

 

[geem]

This is still PBO?

Jonathan

Do you have a galvanising plant at home?

 

[Neeves]

No need - it would be like shipping coal to Newcastle.

We have 4 or G HDG in Sydney, at least one in Newcastle and a TDG plant just outside Newcastle. If you want galvanising, PBO and the tropics come here.

You seem, worryingly, easily swayed - but if you need to be convinced with hard evidence, rather than unsubstantive and subjective information: -

Visit your nearest Sherardizer, explain the background, and ask for 1m of G100 chain, ideally 8mm or 10mm, to my spec and test it alongside your rode. Report back - I'm confident the results will substantiate what I say (and have done - I put my money where my mouth is).


One of the owners of this business followed my advise, for his yacht, see below - you would be in good company. Norman R. Wright & Sons – Custom Boats Since 1909 - he changed from 10mm to 8mm. Alongside his new rode he would have received matching connectors and (I don't recall) a Boomerang. But of course he did not have the experts on PBO to show him the error of his ways.



or stick with YouTube evidence and stay stuck in the past.



If Peerless (+ Dashew and Starzinger) were a set of charlatans they would have been shown up as such decades ago. Gal G70 is well established. Against all the verbiage Peerless survive and Dashew and Starzinger both remain highly respected. The US Navy seem very happy and are saving money by using TDG HT chain from Spencer Inc in New Jersey -

But hey its PBO it must be gospel truth - and I should become, or am?, a purveyor of fiction.



Jonathan

 

[geem]

No need - it would be like shipping coal to Newcastle.

We have 4 or G HDG in Sydney, at least one in Newcastle and a TDG plant just outside Newcastle. If you want galvanising, PBO and the tropics come here.

You seem, worryingly, easily swayed - but if you need to be convinced with hard evidence, rather than unsubstantive and subjective information: -

Visit your nearest Sherardizer, explain the background, and ask for 1m of G100 chain, ideally 8mm or 10mm, to my spec and test it alongside your rode. Report back - I'm confident the results will substantiate what I say (and have done - I put my money where my mouth is).


One of the owners of this business followed my advise, for his yacht, see below - you would be in good company. Norman R. Wright & Sons – Custom Boats Since 1909 - he changed from 10mm to 8mm. Alongside his new rode he would have received matching connectors and (I don't recall) a Boomerang. But of course he did not have the experts on PBO to show him the error of his ways.

View attachment 195930

or stick with YouTube evidence and stay stuck in the past.



If Peerless (+ Dashew and Starzinger) were a set of charlatans they would have been shown up as such decades ago. Gal G70 is well established. Against all the verbiage Peerless survive and Dashew and Starzinger both remain highly respected. The US Navy seem very happy and are saving money by using TDG HT chain from Spencer Inc in New Jersey -

But hey its PBO it must be gospel truth - and I should become, or am?, a purveyor of fiction.



Jonathan

Jonathan, you are not a liveaboard. You sail the season then lay your boat up. Our chain and anchor are on the seabed full-time unless we are sailing. We don't use marinas if there is an option to anchor. The demands on our chain and anchor galvanising are extreme. The salty Caribbean is also very warm. This environment is as tough as it gets for galvanised steel. We will need to replace it all every 3 years because we can't have the chain regalvanised there. It's simply not worth dropping to 8mm G70 for such a short lifespan. If I had a catamaran, I would likely go stainless at considerable expense.
We have just finished stowing our 6th full car load of gear onto the boat. It always surprises me how the boat just absorbs the mass of gear. A small saving in weight for 8mm instead of 10mm chain, on our fully loaded 19 tonnes boat isn't worth worrying about.

 

[Neeves]

Jonathan, you are not a liveaboard. You sail the season then lay your boat up. Our chain and anchor are on the seabed full-time unless we are sailing. We don't use marinas if there is an option to anchor. The demands on our chain and anchor galvanising are extreme. The salty Caribbean is also very warm. This environment is as tough as it gets for galvanised steel. We will need to replace it all every 3 years because we can't have the chain regalvanised there. It's simply not worth dropping to 8mm G70 for such a short lifespan. If I had a catamaran, I would likely go stainless at considerable expense.
We have just finished stowing our 6th full car load of gear onto the boat. It always surprises me how the boat just absorbs the mass of gear. A small saving in weight for 8mm instead of 10mm chain, on our fully loaded 19 tonnes boat isn't worth worrying about.

I've already agreed that the weight savings for your size/weight of yacht are irrelevant and primary reason for using G70 is to save weight. Lighter yachts would be a different analysis to yours

Most yacht owners are not liveaboards and again have a different analysis as many owners will sell their yacht long before the chain needs to be ragalvanised. Owning a smaller/lighter yacht where the chain has a longer life, because the owner is not a livaboard, will benefit from lighter chain as the yacht will return a better performance.

This forum is not exclusively for liveaboards and the decisions liveaboards make may have no relevance, at all, to those who are only able to sail at weekends and an annual 2 week in the summer.

Many of my, and other contributor's comments, are often for the majority of members - not the few.

Downsizing from a 10mm G30 to a 8mm G70 has considerable merit, especially if you make the change on a new yacht, say of 10t displacement. Less weight in the bow, more space in the chain locker, smaller (cheaper) windlass, smaller power cables, lower electrical demands - with the occasional usage the rode might last for 10-12 years. Yet you want to impose your requirements on the majority of members.



This is a liveabord yacht, another one that believed in my ideas.. The couple are sailing round the world, though their plans were considerably altered by covid. They started from France, rounded Cape Horn, sailed to Australia then back across the Pacific and up the Atlantic coast. They changed from 8mm G30 to 6mm TDG coated HT chain, in Australia. Your ideas and those of Noelex are simply unaacceptable - but the size of yacht is more common that a 50' aluminium vessel or your 20t yacht. Weight and space are serious issues on a smaller yacht. These are true liveabords and sailors - crossing oceans in such a small vessel is considerably different to sailing across the Atlantic and sitting in one geographic location for a few months and then sailing back. They don't anchor as much but the weight savings are critical. I cater for demands beyond the few liveaboards in palatial yachts on this forum.

Jonathan






.

 

[Neeves]

Another convert, and quite a big yacht - a Bowman 48. Changed from 10mm to 8mm. A UK yacht, a member here. Did an ARC. They are another user of my ideas.

Sorry but I don't get pictures of every yacht and some of the pictures I purloin



Whereas the majority of converts change from 8mm to 6mm and most yachts are in the 35'-40' and most are that condemned group of "weekend warriors" - there are the occasional larger yacht and owners that might be classified as 'liveaboards'.

But supplying 1,000m of down sized rode - I must be getting something right.

The 1,000m will increase as an owner is just waiting for his 100m of 8mm chain to arrive and he will join the ranks of the converted once it is TDG coated..

Jonathan

 

[noelex]

But supplying 1,000m of down sized rode - I must be getting something right.

This indicates you are supplying a large quantity of hi test thinner chain.

There is nothing wrong with selling products, but any commercial interest should be openly disclosed to the forum, especially if you are actively promoting the products where you have a commercial interest.

 

[Neeves]

Reiterating

I'm not advocating G70, if you want G70 there are a number of vendors, though for the UK you will probably buy from Jimmy Green. However you will have no idea of the galvanised coating thickness - because it is never (that I am aware of) specified and is typically 80 microns or less, sometimes a lot less. Noelex galvanised chain life on which he bases his comments - he has no idea of the gal thickness - and thickness (and quality) determines chain life. The best quality Hot Dipped Galvanised coating is with a new bath, of pure zinc. Quality reduces with use as the bath accumulates Fe. You cannot increase gal thickness as a thicker coating is prone to flaking - the whole lot can peel off. You can check for adhesion by using Vyv's twisted link test (but this does not define gal thickness).

I advocate Thermal Diffusion Galvanising. The process allows accurate coating thicknesses and the coating is harder making the coating more abrasion resistant. My specification is 100 microns, 20% more than the best you will get from HDG and the coating is harder. At worst you chain will last 20% longer, because its thicker. It will also last longer, than 5 years, because its harder. If the US Navy think TDG is a better process then their conclusions are good enough for me - and I note the comments of long term cruisers - but prefer the US Navy testing regime.

If you cannot be bothered contacting and discussing your needs with TDG processor - than you cannot be too bothered about increase chain life by 20% +. 20%+ means if you are a live aboard you should get 5 years + rather than 4 years (or 36 months rather than 24).

A 4 year life is 'typical' for HDG except there is no typical. Abrasion depends on the hardness of the seabed, calcite is less abrasive than silica. If you anchor in acidic muds life will be reduced, significantly, becuase Zn and Zn alloys are attacked by acid (which is one reason acid is used to clean chain, pickling, before galvanising). You only need to anchor off an Asian or S American nutrient rich river or in an old European dock and life reduces to months - not years.

There are simply too many variables to be definitive. The best you can do is to talk to the galvaniser. Explain the environment in which your chain is used - and cross your fingers. It merits note - very little galvanised steel is subject to abrasion, for the simple reason - significant abrasion means the gal is worn off so quickly - its a waste of money making the effort. Steel beams, for example, are subject to atmospheric attack - not abrasion etc etc. We have a cantilevered galvanised steel platform for our car, we live on a very steep slope. The sea is 200m away. The platform is now 25 years old - and looks as good as new - no abrasion no atmospheric attack - the gal coating is more than adequate.

You Tube 'evidence' and subjective comment on gal life both suggesting small chains a shorter life than bigger linked chain - lacks any respected data without knowing the thickness of the gal. Gal coating can be 40 microns or 80 microns - of course the life will be different - nothing to do with link size but a lot to do with the galvanising coating. Shiny gal is not galvanising but the zinc coating left on the product - looks good, but is meaningless - zinc is soft and wears off quickly, Zn/Fe alloys are hard and need time in the zinc bath to develop - time in a hot bath is money, guess what the galvaniser might do - most or all of his product will not suffer from abrasion - he knows you will not measure the gal thickness. His business is gal coated cantilevered platforms - why would he worry about abrasion (40 microns might be more than adequate ).

Jonathan

 

[Neeves]

This indicates you are supplying a large quantity of hi test thinner chain.

There is nothing wrong with selling products, but any commercial interest should be openly disclosed to the forum, especially if you are actively promoting the products where you have a commercial interest.

Noelex, are you now a Moderator. I'm aware of forum rules.

To sell something or be paid for my efforts would require considerable attention to bureaucracy. I'd need to establish a company, take out liability insurance, fund the purchase and processing etc etc. I'd need to charge GST, (VAT) I don't need the aggro and I'm fortunate - I don't need the money, nor tax return etc etc.

I don't sell anything. The raw chain is bought by the yacht owner, the TDG process is paid by the chain owner. All I do is indicate where the owner can buy the chain and the quality he needs and I provide, free of charge, a facility to measure the gal thickness. I'm not paid for anything.

Sorry Noelex but your suggestions are insulting and have no basis except you want rid of me from the forum. I have been expecting your comment - at least you are predictable.

I developed the process, I define the specification of chain and coating thickness needed - it was all documented in an article in Cruising Helmsman. I am asked for advice - I give it freely - I'm happy to share my knowledge. I don't advertise - my experiences are from word of mouth. The Bowman owner learnt of me through YBW, the French owner knew of me through Cruising Helmsman etc

I'm flattered and it suits my ego to be involved and trusted.

Interestingly some cowboy thought he could profit from my process but omitted to demand a coating thickness - it was an unmitigated disaster.

My bridle plate design and Boomerang are both open source - but Viking asked if they could add them to their portfolio. Again - I was happy to have my ego stroked. I don't make any money nor know how many they sell.


I did think of establishing some form of business but rejected the idea as frankly I hate 'selling'. As I said I cannot be bothered with the bureaucracy, company registration etc etc - I'm retired. I don't need money (except it would be nice to start life again - knowing what I know now - then I'd think differently.

So Noelex I'm here for a bit longer, a thorn in your side. You must be very frustrated to feel it necessary to make post 38. You got rid of me in Cruisers Forum, which being arrogant was CF's loss, not mine. But keep trying.

Jonathan