I’m curious about welding anchor chain links together. Anyone who wants to extend their chain needs it to pass through a windlass, and all chain is welded, isn’t it?

Why not have a qualified welder join two lengths of chain, and then monitor it for corrosion?

Tom Fox

Vyv Cox replies:

Modern chainmaking is completely automatic, using the latest, sophisticated machinery.

Not only is each individual link welded electrically under carefully controlled voltage, but every link is proof tested immediately after it has been welded.

Finally, lengths of chain are batch tested by the importer – at least it is in the case of Chinese-made chain imported into the UK.

Despite this sophistication, it occasionally happens that anchor chain is produced with below-standard welds.

In tensile testing, the chain pictured failed at about half of the theoretical load.

Inspection showed the welds to have been made poorly, probably due to poor voltage control.

The two ends of the link have not been melted together properly, and it appears there are cracks between them, in this case, not even disguised by a coat of galvanising.

For grade 30 and 40 chain, which is not heat-treated, it is theoretically possible for a good welder to make an adequate join, although of course, it would be necessary to trust his skill in the absence of a tensile testing machine.

Higher grades of chain, grade 70 and above, also including Crosby and similar joining links, should not be welded as the process would destroy the heat treatment that provides the additional strength.

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