When to replace anchor chain?

[julians]

My boat is 11 years old now and is on the original anchor chain. Is there a concensus of opinion on when to replace the chain.

Ive never had a boat this old before so havent really had to consider this.

It looks a bit rusty, especially the anchor end of it,but generally looks ok. i have no idea if it will go on giving good service for another 20 years, or whether it should be replaced soon.

Any words of wisdom?

 

[[2068]]

You need to replace it when the links are getting thinner and degraded, compromising the strength of the chain.

You might want to replace it at some point before then, simply because having a manky / rusty chain aboard looks a bit rubbish, and can cause rusty stains on the boat.

 

[julians]

How much wear is too much wear?

 

[[2068]]

How much loss of strength are you prepared to tolerate?
The saying about "the weakest link" does really apply here.
I wouldn't be happy with more than 10% loss.

One option (if your chain is long enough) would be simply cut off the rusty section near the anchor and re-attach, if it's only a couple of meters.

.

 

[noelex]

My boat is 11 years old now and is on the original anchor chain. Is there a concensus of opinion on when to replace the chain.

Brush off the rust and measure the wire diameter with calipers at several points where the rust appears most severe. There are different opinions on what constitutes an unacceptable amout of loss, it depends on factors such as whether the chain is oversized, but 10% is a reasonable starting point.

However, if it has lost its galvanising, the rust staining is annoying so most people replace or regalvanise at this point.

 

[julians]

Thanks all,will take a closer look at it later

 

[noelex]

I think most people realise this, but it is still worth stating that a 10% loss in thickness translates to more than 10% loss of strength. I think 19%, if my mental arithmetic is correct (assuming it is not hardened. If it is it will loose more) but this is generally still OK as anchor chain has a reasonable safety factor, although the safety factor is reduced with more recient chain sizing advice.

 

[[2068]]

I make it something like 17% loss of cross-sectional surface area if the radius has shrunk by 10%.

 

[Bandit]

Look at both the anchor end of the chain and the boat end, the bitter end, that should be connected by a short length of rope to the boat so you don't loose it but you can cut it free if you have to in a hurry.

Normally the bitter end is more corroded than the anchor end.

Assuming you have an electric anchor windlass normally the replace it time is when it jams in the gypsy of the winch due to rust build up.

You can get it re galvanised or replace chain with new, if you do make sure it is anchor chain calibrated for the gypsy. A ggod chandler will source Calibrated Chain and possibly let you have a short length to try for link size in your gypsy.

 

[julians]

That sounds like good advice,i have no issues with jamming in the gypsy yet.