Life of s/s anchor chain

I just wonder whether the reduced friction actually works against the chain's main purpose in helping to anchor the boat. In a correct anchoring situation there will always be a considerable (deliberately unspecified) length of chain lying on the bottom, and relying on its friction with the mud / sand to ensure a straight pull on the anchor. I've always felt that the comparatively rough finish of galvanised chain helped with this.
 
Difference between tarnishing and corrosion, in my parlance, is largely one of degree.

I would suggest that 316 stainless steel will rarely suffer significant general corrosion in seawater, although there are clearly other forms that it will. Some examples of corrosion types it could suffer from in this context include galvanic, pitting, crevice. These could produce a heavier rust deposit.

If the corrosion product polishes off I would call it tarnishing. If not, then one of the above is probably the cause. Usually a microscopic examination is sufficient - galvanic implies contact with another metal, pitting likely if an inferior grade such as 304 has been used, crevice I think we have covered.
 
Can I ask for clarification on "plastic deformation" pls ?

AFAIR from my OU course in materials, elastic deformation is when e.g. steel deforms and recovers its original shape.

"plastic deformation" is when the metal changes shapes under e.g. bending or tension, and then doesn't recover.

My concern is that a stainless chain could - under heavy load - undergo elastic deformation, and then if overloaded, experience plastic deformation. At that point, do its properties (breaking strain, fracture resistance, etc) alter markedly, and would a chain have to exhibit visually checkable deformation before it became prone to failure ?

FWIW, I use galvanised chain, but have stainless connectors /forums/images/graemlins/blush.gif
 
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"Generally" perhaps the people who argue against stainless chain are similar to those who argue against the new generation of anchors - Wasi, Rocna, Manson etc.

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Without seeming to be rude ............. rubbish.

Do you really argue with the logic of visible detrioration of galvanized vs no warning Stainless ? Sorry but Galv. chain is easily seen to past it's prime ... stainless cannot. You will NEVER know when stainless is to fail.

If stainless was the answer to the problem - why don't commercial operators go stainless ? maybe it's because life depends on identifying possible failures.
Lift keel wires ... why specify Galv ... lets go Stainless wire ... Yes - you may but not me. I would prefer to see it deteriorate and change than think it's fine because it has no visible deterioration.

Dear oh dear ..............
 
Has any forum member ever had a stainless anchor chain fail on them? We have all heard rumours but I have never met anyone who has had this misfortune. I personally think the risk is very small.
 
Probably not valid because how are you going to find same number of Stainless chain users to galvanized to make fair comparison ? How many carry all stainless anchor sytems - very few I would suggest.
 
That's an interesting point! I have never heard of a stainless chain failing either, I'd be very interested to know if there are any confirmed instances.

But I am still none the wiser as to a probable lifespan, just to try and make an evaluation how long would you expect a ,well maintained, galvanised chain to last? Or is that an impossible question to answer?

www.gerryantics.blogspot.com
 
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That's an interesting point! I have never heard of a stainless chain failing either, I'd be very interested to know if there are any confirmed instances.

But I am still none the wiser as to a probable lifespan, just to try and make an evaluation how long would you expect a ,well maintained, galvanised chain to last? Or is that an impossible question to answer?


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My galv. system is in its 10th year of service with me ... that's chain and rope as well as shackles / anchor ... and they were with boat when I bought it. I have no plans to change any of it in near future. Boat is mid 70's and I suspect I may have original gear ...
 
Both stainless and galvanised should last 'for ever' in the context of yacht equipment. With galvanised you'd have to re-galvanise every 6 to 10 years if it is used regularly, and with stainless you ought to inspect for corrosion. Obviously if you have used the gear in very extreme conditions - hurricane, etc. - you would want to check it even more carefully.

Stainless is the way to go if you can afford it -- though you need to be aware of the danger of crevice corrosion but that applies to all stainless used in load bearing or safety critical applications.
 
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