Lifespan of SS standing rigging

KAL

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Can anyone advise on the typical lifespan of standing rigging for a boat used as a normal cruising yacht (no racing)?
 
Some people - inc some insurers - say 10 years, though I make my over-specced' and lightly tensioned rig last a bit longer.

The snag with stainless steel is it 'age hardens' even when not being given a hard life.
 
16 years or once round the world (whichever is less) or so an Open 60s rigger told me.

I've only had stainless rigging break at its entry to the swage, usually the mast end, and only once had a standing rigging wire actually part.
Apparently much more likely to fatigue fracture are stainless steel rigging screws.Lulu (the rigger) only used bronze adjusters.
It's worth making a minute inspection, at regular intervals, of all your rigging especially at mast-entry end.

Far more stressed than other rigging or masts are those "go-faster" bendy masts with 3/4 rig and keel-stepping. Not only have I had 4 standing rigging wires fatigue fracture but also a mast.
 
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The snag with stainless steel is it 'age hardens' even when not being given a hard life.

Nonsense. Age hardening is a very specific metallurgical process requiring two heat treatment cycles, typically to between 200 and 300 C. It is also known as precipitation hardening, used in superior stainless steel alloys such as 17/4 PH. The hardness of 316 stainless steel, usually manufactured in a work hardened condition for cables, rigging fittings, etc will remain totally unchanged throughout their life.

Virtually every rigging failure that you or I will ever see occurs due to fatigue. Cracks initiated at stress raisers, such as swaged ends, turnbuckle changes of section, holes, etc.
 
I replaced my standing rigging a couple of years ago. It was the original rigging, and the boat was coming up for its 20th birthday and I anticipated having to get a survey for insurance purposes. In the event, my insurer didn't want a survey until the boat's 25, so I could have waited!

Many rigging failures are the result of vibration, usually stemming from the rigging not being tight enough.
 
According to Seldén the spars manufacturer age has very little to do with life span. What counts is miles sailed.
Their advice is to renew standing rigging after 20 000 miles. But that figure is valid only if the rig has been correctly tensioned.
So too lightly tensioned – which is very common – means renewing well before 20 000 miles.
 
Must admit I understood that S/S weakened or became less flexible (I had always heard this as work or case hardening?) used or not although obviously more when used..

Last time I spoke to a rigger about old rigging his response was, it looks good? No stranding cracks etc? your not racing then its probably fine.

When I did finally replace some of it it was obviously past its working life. I could see it was no longer straight and true, then I work with wires regularly in my job.

From what I know its the terminations that normally give up first...
 
Nonsense. Age hardening is a very specific metallurgical process requiring two heat treatment cycles, typically to between 200 and 300 C. It is also known as precipitation hardening, used in superior stainless steel alloys such as 17/4 PH. The hardness of 316 stainless steel, usually manufactured in a work hardened condition for cables, rigging fittings, etc will remain totally unchanged throughout their life.

Virtually every rigging failure that you or I will ever see occurs due to fatigue. Cracks initiated at stress raisers, such as swaged ends, turnbuckle changes of section, holes, etc.

Not nonsense, and you are not the only trained engineer in the world. :)

The clue is in the word 'age', nothing to do with tempering or other heat treatment.
 
The two failures I have experienced were both non-wire related. One a mast-to-rigging lower shroud flange and the other a shroud through-deck V bolt. The implication being that changing the rigging should not stop at the wires and turnbuckles.
 
AFAIK my rigging is original & the boat was built in 1973, so it can last up to 40 years & counting. But I never use the sails . . . :p

Well, not as often as I would like, anyway.

The boat is a Westerly Ketch so the masts are short & fat & the rigging pretty strong. I might be less prepared to risk what others tell me is imminent death & injury if it was a newer boat with a lighter, taller rig. My insurer has never set an age limit on the rig or asked for surveys in the 25 claim free years I have sailed her.

I must just be lucky I guess.
 
Not nonsense, and you are not the only trained engineer in the world. :)

The clue is in the word 'age', nothing to do with tempering or other heat treatment.

So you think the properties of metals change as they get older?

There are a few cases in which the hardness of alloys increases, after very specific prior heat treatment, aluminium-copper being the best known example. Certainly not in 316 stainless steel.
 
Virtually every rigging failure that you or I will ever see occurs due to fatigue. Cracks initiated at stress raisers, such as swaged ends, turnbuckle changes of section, holes, etc.

Vyv, does the use of swageless ends make it less likely to be a stress raisers or does their use give rise to their own set of problems?
If so, what are they?
 
Vyv, does the use of swageless ends make it less likely to be a stress raisers or does their use give rise to their own set of problems?
If so, what are they?

It's a good question. I suspect that they are probably better from a stress-raising point of view. There is good radiusing around the hole where the cable exits from the cover, I guess that the compressive stress in the swaged type is probably greater than with swageless ones and the point where the greatest stress-raising exists, where the cable meets the cone, is protected from bending by the cover.
 
So you think the properties of metals change as they get older?

There are a few cases in which the hardness of alloys increases, after very specific prior heat treatment, aluminium-copper being the best known example. Certainly not in 316 stainless steel.

When I changed my rigging on my last boat the old wire was so much stiffer than the new wire. What causes this hardening? Does the wire get brittle with this increase in stiffness?

On my current boat I suspect most of the rig is original (1980). I am planning on going trans-Atlantic but with a quote of £5k for replacement of the rig for both masts I am reluctant to replace it if it doesn't need it. A rigger has inspected the whole lot and only recommended some minor work. Nothing mentioned about wire replacement. Would you replace it?
 
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