Standing rigging Replacement

[milfordman]

My standing rigging is 7mm stainless steel 19 by 1 strands. I have heard it said that it should be replaced every 10 years. I have never been sure if that means 10 years after it was made, irespective of whether it was used at all or 10 years of permanant use. In the case of my rigging, it was first fitted 17 years ago, but it has only been supporting a mast for approx 6 years if you count up all the time in comission. When it was 10 years old with 30 months total in comission. She was in Westport Mass. (When I first took over the boat ). The mast had been down for the previous 4 years, and the running rigging had been stolen, so it was all being replace with new running rigging. I do not profess to be an expert on rigging, but I looked for broken strands in the wire and cracks in the turn buckles etc or grooves in the clevis pins. All the above to my untrained eye looked ok. I asked the rigging supplier to send thier surveyor to check it over, which they did, and he said it was ok. I consequently sailed her back via Cape Cod canal, Halifax, St. Johns, Cross haven and Falmouth. Two months ago when I put her back in the water I again checked it out by my eye, and could not see any thing to be concerned with. The rigging looks as good as new, the boat is an Ebbtide 33. Is there any test I could do to determine if it is ok, or must it be changed even though it looks ok?

 

[Talbot]

Older galvanised rigging was much easier to survey, if there were broken strands, or corrosion, it was time to replace.

With stainless there is rarely any outward sign of problems prior to the most obvious sign (i.e. the mast falling down) The normal recomendations are 10 years for average cruising and 5 years for racing. If/when I am a liveaboard, I will reduce the interval from the 10 years based on continuous use.

Most insurance companies insist on a receipt to show rigging replacement within the 10 year period before they will pay out on a new mast and sails following rigging failure - your call

 

[wotayottie]

As far as I am aware, the 10 years is an insurance industry statistic based on claims - certainly stainless steel stored unused doesnt suddenly fall apart on its 10th birthday! And its only certain insurance companies so best talk to yours and find out what its attitude is.

There is no way anyone can give you sensible advice on the life of your rigging - your use of the boat is hardly typical of the coastal sailing that most of us do in standard plastic boats. So you are doing the sensible thing in checking the wires yourself. You need to use a magnifying glass, and you need to concentrate on the places where the wire enters the fittings. You are less likely to get a fatigue failure in the middle of a run of wire where there are no fittings and more likely at the point where the wire enters a fitting and gets most bending. Look for broken strands and for rusty lines in the body of the fittings. If you see any of the latter, try to polish them out to see if the are simply the folds made in swaging or cracks. Any doubt, throw them out - life is worth more than the minor cost of rigging wire.

A lot of nonsesne is talked about galvanised wire. Back in the old days (50 years ago or more) when mild steel was mostly made in blast furnaces /BOS vessels and stainless was made in small arc furnaces or even induction furnaces, there was a much larger difference in fatigue life. Stainless in those days was full of inclusions which triggered failure in use. You can often see them on the blades of old stainless knives.

But as things have progressed, stainless has become far cleaner and less fatigue prone. It will still fail as will mild steel. Whether you see it earlier on mild steel which traditionally should be soaked in some sort of gunge or on stainless is debatable.

 

[PeterGibbs]

I agree. If you have been up and looked very closely at the points where the wire enters the fittings, and the fittings themselves, you will have done what's needed.

With rigging we are really working the odds. By all accounts rigging that is routinely and closely inspected does not generally progress overnight from being sound to failure. Metal fatigue is a progressive condition - usually. The odds are that your rigging, as described, is still fit for purpose. That's the view I take of my own rig.

However, there is one more consideration. For most rigs, failure of the forestay will bring the whole rig down 100% of the time. And it's not so easy to check this stay when there's furling gear in the way. Replacing this stay on a precautionary basis seems prudent, but again, cannot in itself guarantee 100% reliability. It continues to be a game of odds! How lucky do you feel?

PWG

 

[milfordman]

Thanks toTalbot,Wotayottie and Peter Gibbs for comments much appreciated. I am blessed with steps up my mast, so it is relatively easy for me to check all the rigging regularly. Also my Jib and staysails are fitted with ye olde bronze piston hanks so I can see both forestay and inner forestay at all times. I will speak to insurers to find out their attitude. I will be proposing to replace outer forestay as a precation any way. I take on board the comment that if the forestay fails the whole rig would go down.

 

[jimbaerselman]

Crudely, failures are caused by stress cycles; the number of cycles and the amount of stress (relative to ultimate strength) encountered. Add to this a risk of corrosion once a (tiny) stress crack appears.

If you're not cycling (mast down) you're using very little life - corrosion is the only threat, and only on rigging which has been substantially used.

If your rigging is over-specified, the stress cycles are low relative to the ultimate strength, so your rigging will have a longer life (typical long distance cruising design). If your rigging is relatively light (typical racing/weekend sailor design) the stress cycles will be high relative to ultimate strength. Look at your rigging diameter compared to boats of similar size to see where your boat lives . . .

The main stress cycles are caused by inertia forces on top of the regular wind/sail forces. Lots of long distance voyaging in choppy seas uses life far more quickly than weekend sailing in mainly clement weather. Do you know the rigging's history?

So there isn't a simple answer to your question! And the insurance stats give an average over all of the above factors, which vary so widely . . .

 

[rogerthebodger]

What is realy needed is a cheap and simple way to detect when the stress cracks / corrosion pitting has occured and how bad it is to allow anyone to determin when to change the rigging and no just use some insurance stats that may or may not apply to your particular setup

May this should be the subject of the research project Lemain was looking for