Rigging

[rrees]

I am looking for a tool which will tell me if there is any failure of my rigging i.e. rust etc.
I heard somewhere that there was a device that would check the electrical characteristics of the cable i.e resistance capacitance etc
Any help would be greatly appricated

Richard

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[Courageous]

Hi Richard - I keep meaning to reply to your email and I'm sorry but have been VERY busy for some time now. Promise will do it soon! Funny you should be posting this query reference rigging since I recently had a bit of a spat over mine. Will tell all soon

Ian

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[Sunnyseeker]

I dont believe th eresistance test is anything more than a guide as Stainless fails due to to stress fractures, as well as corrossion. Resistance wont tell the difference between one strand and 10 still intact. Overall condition and age of fittings is probably more usefull. Stress fractures will start where there has been somne bending, often where there has been a wrap around the forestay with a halyard which then gets pulle tight. However it seems to be that its the fittings that fail most often (from reports I've read) and not the actual wire.

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[Plum]

There is no reliable method of detecting the life expectancy of stainless steel rigging, which is why insurance companies specify periodic (ususally 10 years for a cruising boat) renewal.

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[William_H]

I disagree with Sunseeker as the rigging failure I saw most recently was of 1X19 SS wire which failed at the entrance to the roll swaged area. You may be lucky to see some wires unravell but in this case there was no unravelling noticed until total failure and mast loss. (It was 25 years old) the mast expert reckoned replace turnscrews every second wire replacement although I think if they are bronze you shouldn't worry too much. As for fittings parts that are obviously over engineered should be reasonably safe long term and flate plate tangs seem to be OK. Certainly there is no usefull way of checking the future life expectancy of your rigging. Forget electrical resistance change ultrasonics radiograph or any other non destructive testing. The long term changes are in the crystals of the metal any cracks etc will only be detectable in the last fraction of their life (possibly in the last few milliseconds before failure) So change wire and other highly stressed parts on calender life conservatively at 10 years or if you are willing to take a risk up to 15 years.
I was involved with a traing fleet of 10 foot dinghys that were used about 20 hours per year and stored in a shed. I was amazed at how often the 1/8 1X19 stays would start to unravel at the copper swage. They never broke because the load was so tiny but I can only think it was years of life with salt water occasionally on the wires that caused the failure. Certainly not load or fatigue.
Regards will

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