Rigging renewal

[giraffehappy]

Just bought a Warrior 40 for a circumnavigation(sp?) and it has been over-rigged, with larger gauge stays etc. than normal. It is nine years old, and due to a slightly nervous owner, has only been to France once in its life, and has otherwise not done a lot. We have been told by some to automatically re-rig the whole boat, and by others not to bother. It all looks great, but we have been told about terminal corrosion...

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[Talbot]

depends how soon before you circumwhatsit! conventional wisdom (and the insurance peeps) calls for rigging to be changed after 10 years (5 or less if you are racing) Commonsense says rigging change as near as possible to your circumnavigation.

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[snowleopard]

there is a common myth that rigging should be light so as to break before the boat is capsized. this is b***s. the normal size of rigging should be fine except perhaps in a 360 deg. roll.

when de haviland was having problems with the comet falling apart through metal fatigue, boeing solved the problem by adding more metal. your rig will therefore be more reliable than one with standard sized wire. it's also certain that no insurers will take that into account if a stay fails after 15 years so you will have to renew after 10 years regardless.

the extra weight aloft will reduce stiffness/stability so isn't generally a good idea so when renewing i would go back to standard sizes.

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[AndrewB]

When stainless standing rigging should be replaced is one of the main FAQs on YBW boards - do a search for a range of opinions and options.

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[stokes]

Thought Comet problem was window shape.....

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[Birdseye]

And Boeing didnt repair the Comet either.

Your friendly insurance company will tell you their opinion on the rig. Mine are quite happy with my 20 year old stays since I have the mast down every year and inspect the rigging carefully. Your might not be as reasonable.

If you have Norsman or Stalock terminals then you can take them to bits and check for corrosion. But even if you did so, there is no way you could detect imminent fatigue failure.

If I were doing what you plan, I would re-rig the boat using Stalok since that has to be safer than simply leaving the existing in place. Its also surprisingly easy to do yourself, and way cheaper than useing a rigger. I would take some spare wire with me just in case I had to replace a stay.

At the same time I would examine carefully the bottom and top of each stay to ensure easy articulation in all directions. Fatigue failure is much more likely to come from repeated bending of the wire than simple loading up vide the British Steel boats forestay problem.

Have a good trip. Every cirumnavigator I have talked to says that maintenance is the major problem. You have to be able to diy once you have left civilisation.

<hr width=100% size=1>this post is a personal opinion, and you should not base your actions on it.

 

[boatmike]

I think there are two considerations. One : insurance. Have your IC asked for a survey? Have they asked any questions re rigging age? If they have no wiggle room to refuse a claim then the insurance is not a consideration but check as any reason to refuse will be grasped by a loss adjuster with enthusiasm.
Two : Corrosion/Fatigue.
At 9 years old this should not be a problem but if you want to check any screw collet type of joint you should see corrosion if you take it apart and look. Frankly it should be OK. Swaged joints are of course impossible to check fully. Fatigue is only a problem if the wire is subject to bending or other unusual stresses. If all pulls are straight this should not be a problem either.
Actually people often talk about fatigue in rigging but I have never personally seen a fatigue failure. I have seen wire break because it was not properly installed though. Most common is end terminals that are not able to swivel in all directions and put bending stresses on the wire.
Anyone actually seen stainless rigging break through fatigue?

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[DreamyLady]

Norseman Terminals

I am unable to offer advice regards interval between re-rigging.

Has anyone heard of failure of early type Norseman terminals? The ones with backnuts.

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[Keith]

I was always led to believe that standard rigging was fine for a boat that went down to its designed waterline, as most cruisers will tell you the waterline of old becomes athing of the past and this is the reason for heavier rigging, as the boat is deeper in the water she will not respond as when she is at her LWL so the strain on the rig could become excessive, as a good freind of mine said when we discussed this (and he's a full on racer) there are circumstances especially in the cruiser/racer classes where you can go to lighter rigging as the boats are made lighter than even the designers reckoned on..............keith

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[snowleopard]

i have personally seen two fatigue failures in rigging, both caused by repeated loading along the length of the stay, no bending was involved. one was a stainless toggle, the other was in the length of the wire, about 3 inches from the norseman terminal, so yes, it does happen.

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[boatmike]

That's interesting. Are you sure they were really fatigue fractures though? I suppose it makes no difference if they broke but the simplest definition of fatigue fracture as I understand it is breakage due to repeated vibration or reversals of stress that is very low in comparison with the ultimate tensile strength of the part. I have seen breakage due to stress failure where the item was overloaded or there was a fault in the component causing a stress riser but never true fatigue. I would suspect the toggle as being the latter but must say the wire breaking 3 inches away from the terminal sounds oddly like it could be true fatigue.....
Personally I tend to think the masts and rigging fitted to many cheaper production boats are way under designed for any kind of extended ocean sailing and would be inclined to keep the oversize rig fitted to the Warrior as described. The additional weight of the wire etc must be peanuts compared to the mast itself don't you think?

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[ChrisE]

I'm not particularly technical but would go along with what has been said before and would add that if yuou have roller furling it os well worth paying particular attention to the forestay.

We renewed our rigging the year before we went transat for a year and had the forestay snap about 18 months after fitting. The cause was found to be the anti-tangle thingie for the roller reefing at the top of the forestay. This caused an articulation in the stay adjacent to the swage that led to its downfall. The rigger who mended it commented that it was not unusual to see this sort of failure on long distance cruising boats.

Incidently, we have changed our forestay again this year, 7 years after the initial problem, after indications of a repeat about to happen.

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[boatmike]

I can see exactly how this could happen with repeated cyclic loads at the top bearing of the roller reefing. It would indeed tend to create fatigue over a long period of time and is an excellent tip! I shall indeed look out for it on my own boat.
Just because I said I had never seen a fatigue fracture myself does not mean there ain't no such thing! I have just been of the opinion that many failures are normal stress fractures due to undersize rigging. What you describe would indeed be a fatigue fracture so perhaps I have been over cynical....

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[deckbits]

As a naval architect i read with some concern some of the views on oversized rigging.
During the design process of a rig we must consider worst case scenarios, and build desired areas of failure.
for instance if a yacht was knocked down or broached an oversized shroud or stay that had a design stress greater than that of the chainplate could cause serious problems. It would be far more preferable to lose the rig than to have the chainplate ripped out from the deck and then lose the rig and seriously compromise the survivability of the yacht. Over sized rigging could also cause the collapse of the mast foundations a serious structural failure.
In design we try and build a weak link into the system it is no use having sheeting that will hold enough sail to heel the yacht past an acceptable heel angle.
In a gust it would be far more preferable to have a shackle or sheet break than have a broach and possible loss of the mast.
In my opinion it is best to have someone look at the loadings and specify rigging that is truly fit for purpose considering the worst case scenarios. A rigging calculation should take a naval architect two hours with the correct information available.
www.deckbits.co.uk

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[giraffehappy]

Hi team,
thanx for all your help. Have decided to have the boat rerigged before we go, at present gauges. Will sleep easy.

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[snowleopard]

i can be pretty sure. it was the same stay and the incidents happened within 1000 miles sailing.

this was a forestay connecting two self-supporting carbon fibre spars, as the boat pitched the stay could be seen to go slack then tighten again. the load was well within the strength of the stay but was repeated every few seconds for weeks at a time. at the time of the first failure the boat had covered 10,000 miles and was 18 months old.

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[boatmike]

Sounds very much like fatigue then I agree.

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[giraffehappy]

Hi deckbits, all the rigging and mast was installed after being very carefully worked out by the same company, Z-spars, so hopefully they got the ratios etc. right.
Thanks.

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