10 year standing rigging, why?

[col50]

Originally Posted by sailingharry

I'm a degreed Mechanical Engineer. We study this stuff. Which means, 40 years ago, I could actually speak intelligently about it. Now you are stuck with the storytelling of a forgetful old man.... But, "Once upon a time, as I recall...."


When metal flexes, the bonds between the atoms stretch, and then return to their original configuration. This doesn't change the hardness of the metal.


When metal bends, the atoms actually move. Imagine bending a ream of paper, and the sheets move along each other. In a 100% pure metal, this doesn't harden it. But in an alloy, there are alien atoms. These atoms help to stop the movement of the rest of the atoms, making it harder (often why they are added, such as in steel or bronze). When you bend it, these atoms slide along and collide with (and collect with) others. This permanently modifies the molecular structure of the metal, and it "work hardens."


But then there is fatique. This is where a spring is flexed (but without being deformed -- molecules moving), and it will eventually fail. And the cause of that is lost to too many glasses of wine.....

I agree with everything you say ----- but then there are springs in the escapement's of mechanical clocks that are flexed continuously for decades without breaking. More wine please.

[chrisr]

Originally Posted by sailingharry

This sort of defeats the purpose of insurance. Perfect mariners sailing perfect vessels never have losses. Nearly all losses can be attributed to some lapse of judgement. The idea that "it failed, so it wasn't suitable, so no coverage" and the closely aligned "you ran into it, so you weren't paying attention" or the "you shouldn't have gone out in those conditions" when taken to an extreme makes insurance worthless.

Ah ha !!

i see you understand how the insurance industry works

cheers,

[donradcliffe]

The real answer is that it is complicated. Failure of stainless steel rigging is a combination of cyclic fatigue and chloride stress corrosion cracking. The primary takeaways are:

1. Most rigging failures occur inside swaged fittings, where you can't see them develop.
2. Wire breaks one small strand at a time, so rod has a somewhat longer life.
3. Mechanical fittings assembled with an effective sealant that can keep the saltwater out may last considerably longer than swages.
4. The rate of failure is temperature dependent, so re-rigging should be done more often in the tropics.
5. It is also dependent on stress levels, but many failures do not occur at the highest stress condition.
6. Turnbuckles, toggles, tangs, pins, and welds can also break, but can usually be detected before failure with periodic close inspection.

7. Don't get distracted by clock springs. They are not made of SS.

We learned the hard way in the nuclear power industry. If you want more scholarly articles, Google Chloride Stress Corrosion in Austenitic Stainless steel.

My recommendation--12 years for wire, 20 years for rod, REPLACE EVERYTHING. If you see a broken strand, REPLACE EVERYTHING. Carefully inspect the underlying foundation (tie rods, chainplates) every 2 years or 10,000 miles.

Its cheap insurance. I do all my own work, so its not that expensive. Its is becoming more and more common for insurance companies to total the boat if the mast breaks.

[skenn_ie]

Work hardening. Stainless has shorter life than galvanised.

[sck5]

I was on a boat crossing from Cabo Verde to Trinidad when a shroud failed. We were lucky the rig didnt come down and we could rig a dyneema shroud instead. But the thing is, the whole rig had been inspected by pros before leaving . They didnt pick up on any fault even though it was obviously near the breaking point. It would have been a good idea to replace everything anyway.
But if I werent out in the middle on a long passage I could imagine letting things slide for a while. Rig failure isnt nearly as big a deal when there is help close by

[skenn_ie]

Originally Posted by sck5

I was on a boat crossing from Cabo Verde to Trinidad when a shroud failed. We were lucky the rig didnt come down and we could rig a dyneema shroud instead. But the thing is, the whole rig had been inspected by pros before leaving . They didnt pick up on any fault even though it was obviously near the breaking point. It would have been a good idea to replace everything anyway.
But if I werent out in the middle on a long passage I could imagine letting things slide for a while. Rig failure isnt nearly as big a deal when there is help close by

Was it a swaged shroud or spliced ? One sailing friend had several swaged fittings fail.

Rig failures usually happen when under abnormal pressure. i.e. the worse time. My dad lost a mast once, a chainplate pulled out. The mast floated, upright, moving up n down like a piston. If it had come up under the boat, it wouldn't have stopped.

[captchetco]

I replaced all rigging in 1976 boat in 1992, w US made 316 ss, one size larger than original. Have had it professionally inspected every year, including opening of one or three sta-locks. Replaced forestay at 19 years, due to wear, have cut and added 3 toggles out of 4 to upper port and stbd stays btween 2015 and 2021, to repair broken single strands at top of lower sta-lok. Replaced main mast backstay and triadic stay in 2022, because one side of split main backstay (ketch) failed under way. That is a real life,annecdote of rigging life span.
Sailed PNW 92-96, Mx96-97, PNW 97 -2007,( club racing), MX andCentral America 2007-2023. If using wire, be sure it is US made 316, and use Sta-lock or other quality inspectable terminals..

[boatman61]

Originally Posted by Shaneesprit

True except
Not true in all countries, OP is in Scotland and in the UK it’s generally the owners responsibility to ensure the boat is in condition to sail, (Insurance don’t ask for surveys) obviously then if rigging failure occurs you can’t really claim for loosing the mast.

Its always the owners responsibility to ensure the boat the boat is fit for purpose unless they have a death wish.
Pantaenius always asked for a survey if one wanted hull insurance.
Liability only is something else.
They're out to make money, not make handouts..