Rusty anchor chain - good for another season or two?

[jimbo]

Checked the anchor chain today in preparation for a summer on the West Coast Scotland which will hopefully involve plenty of anchoring. The vast majority of the 60m was in good condition but there were three or four short sections which looked decidedly rusty, probably from where it had
been sitting on wet anchor rode over the winter. The chain is 10mm and about 10 years old.

I whacked the offending links with a wrench to get the flakey rust scale off and gave it a quick once over with a wire brush - and the pictures below are what it looks like afterwards. Unfortunately I do not have a 'before' photo but it was a little darker and had some flaking scale. There was no sign of obvious wear where the two links make contact, nor any deep pitting. I measured the thickness of the links with vernier calipers and they were about 9.75mm each, not much difference from the 'good' conditions links.
The galvanizing has obviously gone in these sections but is there anything else to worry about? I am loathe to condemn such a long chain for the sake of a few sections but would appreciate your thoughts as to whether it is time to replace or not?

 

[Boathook]

The links look ok so I wouldn't bin. Just remember not to leave the chain on wet rope next winter !
I seem to remember that that 10mm of rust is 1mm of rusted metal, so a few flakes of rust is nearly nothing.

 

[Robih]

I’m sure it’s fine, but I’d change it. It blows (a lot) in Scotland and your anchor tackle is mission critical. And rust makes a horrendous mess on deck

 

[vyv_cox]

Your checks confirm that very little metal.has been lost to corrosion. Strength should not be compromised at all. So long as you can cope with rust down the decks there should be no problem with carrying on using it.

 

[William_H]

Rust in chain is far more critical in mooring chains. Here the discoloration is rapid but worse is the wear of the faying surfaces of the links. ie the link gets very this until it fails. At this stage OP's rust is really just cosmetic (can be messy) Just keep an eye on the rusty links after they have been under load for a while. The cahin should be vastly stronger than the holding power of the anchor. The chain is heavy for it's mass not it's strength. (usually) ol'will

 

[Neeves]

I agree with Vyv.

But I have an alternative option.

The rusting sections, small though they may be, have lost their galvanising (probably because you stored the chain with wet rope). The rest of the chain, if cared for, could last for years.

For the future - separate the chain from the rope. Wash the chain with fresh water whenever you wash the decks and make sure the locker drains correctly.

The rusting sections will continue to ccrrode and lose steel. You may not see this as if you anchor frequently the seabed will, kindly, polish and clean the chain for you.


Consider regalvanising NOW as the chain is effectively more than adequate. In 2 years time that might change - and a new 10mm chain is not cheap. I don't know where you are located but if in Scotland then Highland Galvanisers will galvanise chain either at Cumbernauld or Inverness? (somewhere north ). There are other galvanisers, who can process chain, and you might have some recommendations from the members here.


Don't be tempted to paint the chain - it will be a mess within weeks and some galvanisers will refuse to handle it.

Jonathan

 

[Yngmar]

It's fine. Wire brush the rust off and spray on some zinc primer and it'll even stop rusting for half a year before that rubs off.

 

[vyv_cox]

I agree with Vyv.

But I have an alternative option.

The rusting sections, small though they may be, have lost their galvanising (probably because you stored the chain with wet rope). The rest of the chain, if cared for, could last for years.

For the future - separate the chain from the rope. Wash the chain with fresh water whenever you wash the decks and make sure the locker drains correctly.

The rusting sections will continue to ccrrode and lose steel. You may not see this as if you anchor frequently the seabed will, kindly, polish and clean the chain for you.


Consider regalvanising NOW as the chain is effectively more than adequate. In 2 years time that might change - and a new 10mm chain is not cheap. I don't know where you are located but if in Scotland then Highland Galvanisers will galvanise chain either at Cumbernauld or Inverness? (somewhere north ). There are other galvanisers, who can process chain, and you might have some recommendations from the members here.


Don't be tempted to paint the chain - it will be a mess within weeks and some galvanisers will refuse to handle it.

Jonathan

Unfortunately regalvanising has become so expensive due to fuel and zinc spiralling costs that it is now barely cheaper than buying new chain. Outside UK countries with lower labour costs continue to make it worthwhile but in western Europe the practice has almost died out.

 

[jimbo]

Your checks confirm that very little metal.has been lost to corrosion. Strength should not be compromised at all. So long as you can cope with rust down the decks there should be no problem with carrying on using it.

Thanks Vyv - that helps me sleep a bit easier (only a bit - unfortunately I am not one of these people who can sleep like a log whilst at anchor!)

 

[jimbo]

I agree with Vyv.

But I have an alternative option.

The rusting sections, small though they may be, have lost their galvanising (probably because you stored the chain with wet rope). The rest of the chain, if cared for, could last for years.

For the future - separate the chain from the rope. Wash the chain with fresh water whenever you wash the decks and make sure the locker drains correctly.

The rusting sections will continue to ccrrode and lose steel. You may not see this as if you anchor frequently the seabed will, kindly, polish and clean the chain for you.


Consider regalvanising NOW as the chain is effectively more than adequate. In 2 years time that might change - and a new 10mm chain is not cheap. I don't know where you are located but if in Scotland then Highland Galvanisers will galvanise chain either at Cumbernauld or Inverness? (somewhere north ). There are other galvanisers, who can process chain, and you might have some recommendations from the members here.


Don't be tempted to paint the chain - it will be a mess within weeks and some galvanisers will refuse to handle it.

Jonathan

Thanks - will check out the cost of re-galvanising vss buying new. Cheers. Jim

 

[jimbo]

Rust in chain is far more critical in mooring chains. Here the discoloration is rapid but worse is the wear of the faying surfaces of the links. ie the link gets very this until it fails. At this stage OP's rust is really just cosmetic (can be messy) Just keep an eye on the rusty links after they have been under load for a while. The cahin should be vastly stronger than the holding power of the anchor. The chain is heavy for it's mass not it's strength. (usually) ol'will

Thanks - thats good to have confirmed. I can put up with a bit of rust staining on deck, have plenty of Oxalic acid on board

 

[Bilgediver]

Your checks confirm that very little metal.has been lost to corrosion. Strength should not be compromised at all. So long as you can cope with rust down the decks there should be no problem with carrying on using it.

I agree with this Vyv . The biggest killer of anchor chain is not so much surface corrosion but the interlink wear . This is the places where the links wear against each other. The links can appear to be fine but worn half way through.

The interlink wear is more usual on harbour moorings and I have seen chain in our local harbour where the wear has been up to or over 50% of the cross section of the chain.

This chain may not appear to look great however I suspect a tensile test would result in a figure not far from new.
A stiff wire brush and the correct coating will make it look nice. It seems modern galvanising is not as good as it used to be

.

 

[Sea Change]

Wow I wish my chain looked like that.

I don't think you have anything to worry about.