Rigging failure - what breaks?

Conachair

Conachair

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I'm replacing standing rigging at the mo (well I would be if they'd sent the right bl%%dy norseman cones!!!). Which got me to wondering what the most common failure point is, if there is any such consistancy. I'm norseman throughout and going for dyform wire. WIthout being an engineer the weakest point I can see is the sockets for the T terminals in the mast, T terminals themselves are hefty bits of stainless from norseman and look very well engineered. Not really worried about my boat, looking round the marina I think it's tougher than most, more interested really. Tried google but didn't come up with much. Is there a common factor? Bad design? Dodgy crimps?



Padz - Conachair
 
I am replacing my rigging at the moment and have asked several experienced riggers the same question. The answers I have been given are:
1. SS wire work hardens over time
2. SS corrodes - often inside the crimped fittings which causes expansion which in turn causes the crimped fitting to crack and ultimately fail.

It seems that terminals and bottle screws rarely fail except when subjected to lateral stresses through incorrect fitting.

Finally the wisdom seems to be that you can re-use good quality bottle screws once but the T terminals should be replaced. I have not been advised to replace the mast fittings.

As this is such an important subject I must emphasise that I do not speak with any expertise, I have just been quizzing those who claim to have knowledge.
 
Remembering to fill the terminals with silicone could reduce risk from splitting when water turns to ice ....

I remember reading about a steel boat enroute from US to Europe (Martins) and a Sta Lok or Norseman fitting fractured.....
 
That's all the conventional wisdom and based on experience. the only bit of rigging I've ever had break (says she touching every piece of wood in sight) is the swage terminal attaching the lower shrouds to the mast. One of tangs failed due to a poor weld at the seam where it curved outwards to accommodate the various screws etc.

Actually failed just west of Dungeness as we were heading for Dover; we had to slow right down of course and missed the tidal gate. It took forever to get past the headland and we never want to see the headland again!
 
We've had a forestay snap, just below the swage at the top of the mast. Due, I'm told to articulation between the flopper stopper on the roller furling (a cone about 3 in long designed to stop the halyard wrapping around the forestay) and the mast. The rigging had been renewed 18 months before the break...... I'm told that it is quite a common reason for forestay failure.

Also had a the tang on the shrouds snap after boat in collision with rock at 6 knots (not me driving, I hasten to add).

FWIW, I'm damn glad that we have a detachable inner forestay that has helped keep the mast up both times.
 
Have enjoyed 3 dismastings: DIY Norseman terminal on backstay; swaged terminal on lower shroud; old age - never found out what, the rig was cut away and lies on the bottom of the Irish Sea.
 
Tried google but didn't come up with much. Is there a common factor? Bad design? Dodgy crimps?
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Add to those badly assembled Norseman /forums/images/graemlins/laugh.gif
 
I've seen cracks in the T-ball sockets.

About 10 years ago we changed out our lowers on advice that the type of T-ball that we had was prone to fatigue failure across the neck below the ball. The new design looked superficially similar but putting the old and new together showed a difference in the load path.

Fatigue cracking can occur in wires inside swaged fittings. Strands fail progressively until eventually the load is too much for remaining strands and they fail in overload. This is the usual explanation for the 'sudden failure' observation. One minute it is fine, the next it's over the side. One cause is the banana swage, when the friction of the wheels is not applied equally side-to-side, preferentially one point.

A boat was abandoned in the ARC when the chainplates cracked. Again, almost certainly fatigue do to unfair loading. Absence of toggles is often the cause. The famous British Steel forestay failures were of this type. The forestay was unable to deflect in one direction due to a design error in the attachment fitting, preferentially loading one point.
 
Out of curiosity Conachair, what is it costing you to replace your standing rigging?

I'll see you in the Canaries soon, I'll try to leave Lisbon next week if there is a good weather window.
 
Must have spent about 2K (ukp) so far, but I'm lucky in that I was a rigger for years, but in the entertainment side of things, so I got the wire and some other bits with hefty discounts. Hate to think what it would be out of a chandlers in england. Good luck on the way down, Nick. Canaries I like, 50 euros a week in Las Palmas with LX and water. And a throughly multinational sailors bar to swap stories in! /forums/images/graemlins/smirk.gif
 
2k on the standing rigging? jesus, mine will snap and then be replaced with clothesline before i find that kind of cash /forums/images/graemlins/wink.gif

50euro a week? if that's not motivation, i don't know what is! see you soon,

nick
 
Crikey, don´t think i wanted to hear that. 8mm dyform ain´t cheap though, and norseman teeball fittings added up. and there´s spare in that figue as well so maybe not as pricey as it seems.
 
What breaks? high stress rigging. No thats not meant to be flippant just to piont out that tradditionally cruising rigs did not fail if even moderatly maintained but the current trent towards higher aspect ratio 'performance' oriented boats and riggs for cruising means everything is pushed further, needs more maintainance and wears out quicker. Not something you can really change on a boat but worth thinking about when selecting your 'ideal cruiser'
 
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What breaks? high stress rigging.

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Agree completely! Now i really like having a cutter rig but I'd be interested in other peoples take on the matter. Way I see it is wind the wind pipes up you can get rid of the foresail altogether and just have the staysail up, forces closer to centre of the boat and lower down, also shorter stay so catenery effect is much less. If I've got the genny half rolled istm that each time it flogs the forces must be huge, and closer the the centre of the forestay so forces on stay are also increased, more of a point load than a uniformly distrubuted load. And stayail seems to flog less as well.
Is my logic flawed here? Anyway, the boat seems happier that way.
 
Well, sort of... I agree..

We have the best of both worlds imho.. a removable forestay..(we dont use runners on the main, but have them on the Mizz for the Mizz staysail) we use the the storm jib as a worker on the inner stay if needed.. mind you, like has been said, the older rigs are FAR more robust, massively redundant.. not the 3 string bathtubs of the last 20 years lol...
Too many try to use the genny as a one size fits everything.. it doesnt... the tri is also on its on main mast track.. it is also a orker after 2 reefs.. well, to be fair on a ketch.. we dump the main after rolling the genny half way.. go jib n jigger, then storm jib n jigger.. then tri.. easy really.
AND we sit walm n dry in the pilot house letting mr hydrovane do his stuff...

another gin dear ??? /forums/images/graemlins/laugh.gif
 
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the tri is also on its on main mast track..

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Got a storm trisail (have I got the name right? Sturdy mini main on a seperate track?)as well but never had it out of it's bag. Yet! But where does it sheet to? Should really have a play before before i have to do it for real. Right now having more fun playing with google, got maps in a web site! Probably like falling out of bed for you computer meisters but exciting for me. www.conachair.co.uk
Playing with jalbum now - http://jalbum.net/ You can link yer piccys to google maps. Only web access is in bar so concentration gets much harder with each beer!

Otra Cerbeza? /forums/images/graemlins/laugh.gif
 
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