Re: Anchor Chain


James Alton
 

Nick,

   I would be looking at about $4,400 USD  (I found a US supplier)  for 300’ of the 8mm which is a little less than 2.5 times the cost of the Aqua7 grade 70 that we are using now.  (We are using the grade 70 8mm because we can fit 100 meters without issues of knocking down a chain castle as the chain piles up in the locker.  The grade 70 8mm is also supposed to be as strong as the 10mm G40 we replaced and puts less weight in the bow)    As you point out the Cromox is amazingly strong for being stainless,  maybe 7 percent weaker than the Aqua7 quite a surprise to me.   So if the Cromox was good for 10 years and I replace my Aqua7 every 5 years instead of regalvanizing the cost difference would be about $688 for 10 years or an additional $69 per year if I have my math correct.   A replacement every 5 years would be a $507 per year premium though I suspect that there would be some resell value in 5 year old Cromox chain that could help reduce the cost differential. My primary interest in the Cromox stems from the comments that seem to indicate that it runs more smoothly  (reliably)  through the Gypsy but I do not have any actual experience with stainless chain on a gypsy.   I can tell you that once my Aqua7 developed some surface corrosion and roughness that it began to occasionally skip/slip on the brand new Gypsy supplied with the chain.  At any rate the brand new G7 chain seemed to run smoother when it was new and smooth and I assume that the stainless chain would remain pretty smooth over the years.  I view the anchor windlass as one of the most dangerous components of the boat so if it is possible to improve the safety of the operator for $69 per year that sounds worthwhile.  Can anyone that has used the stainless and the galvanized chains please comment on whether they see a difference in how the chains run on their windlass?  My primary concern about the Cromox is the potential for crevice corrosion that could cause a failure.  I have been searching for evidence of failures on the Web and so far have not come across any but perhaps there are not a lot of people using stainless chain?  I note that pretty much all of the anchor swivels used are now stainless.  I understand that the German manufacturer for Cromox can inspect, treat, repair if needed.  I think that they can also issue a new warranty for their Cromox after such an inspection though I have not looked into all of the details.  I also note that Cromox chains are also sold for overhead lifting operations which could indicate the reliability must be pretty good to get this certification.  I will stay with my galvanized steel for now but would like to learn more about the Cromox option, thanks for any input.

Thanks,

James Alton
SV Sueno
Maramu #220

On Sep 14, 2020, at 12:19 PM, ngtnewington Newington via groups.io <ngtnewington@...> wrote:

I get the attraction of Cromox;

No rust

Stacks nicely,

Clean 

the 10mm chain has a MBL of 10197 Kg, so strong too

BUT one hundred meters would cost about £6115 (Jimmy Greene) including VAT but not delivery.




Accastillage Diffusion, a French chandlery with outlets all over France and one in Lanzarotte( where I had 100m delivered at no charge as it came with the regular container shipped from France) 

sells Grade 70 galvanised chain made by  Chaineries Limousines with a MBL (breaking load) 11217 Kg  for Euro 1390 i.e. about £1200.

(Grade 40 has a MBL of only 5000 Kg!! so it is twice as strong as the 40 and even stronger than the Cromox, but at less than 20% of the cost….




How long will the Cromox last? It is really hard to say….5-10 years sounds about right. Will it stretch? I do not think so. So there will be no way of knowing when it needs replacing….maybe it is like standing rigging and will last 12 years…I do not know.

How long will the galvanised grade 70 last?….after five years it will probably be looking a bit rusty. One can inspect the links for elongation. One can have it re-galvanised though apparently this will reduce the strength very slightly, by maybe 10%. 

Of course it is not easy to get re-galvanising done nor is it easy to buy grade 70 chain…

Nick (now back in the UK)
Amelia (ashore in Leros)
AML 54-019





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