Failure of swaged terminals.

[feetup]

Here I am again with another question. Perhaps this is a "nerdy question", but I'll ask here because it is definately a rigging question.

Has anyone experienced, or examined the results of the failure of a swaged terminal on stainless steel standing rigging?
I have read that a swaged terminal over a certain age is a failure waiting to happen and that unless you replace your standing rigging regularly the whole thing is going to come down and we're all going to die!
I'm not sure how to word this without my usual excess of verbiage but I guess my question is this...
My terminals have passed both die penetrant examination, and, just to be sure, I did an ultra sonic inspection, and found nothing probative. Such testing would be adaquate for a stainless pressure vessel according to ASME standards, but my paranoia continues. Is this a case where the work hardening of the material during swaging causes embrittlement and a propensity toward cracking or is it a case where the wire pulls from the swage when loaded beyond certain limits even though the terminal shows no signs of cracking or failure? It doesn't seem plausable that stress corrosion cracking would be the culprit since this type of failure due to chlorides is very rare below about 60 degrees Celsius.
Any thoughts?
The boat is a U.S. 25, the same as an early 80's Trident. It has 5/16 rigging, double lowers, single spreaders, deck stepped mast. Definately NOT a blue water boat. I doubt it will ever see anything in excess of 15 knots of wind.
Thanks all.

Feetup

[Tim]

There's not a definite life expectancy of a swaged terminal. Obviously, you have read some sensationalist articles on rigging, which are common. To be fair, it is important to carefully inspect rigging of any age, but articles that make it sound so desperate aren't really doing anyone any favors.

No one has yet to come up with any sort of valuable data concerning the actual lifespan of rigging. There are plenty of boats out there with 20-or even 40 year-old rigging and swage terminals. Is this smart? Not necessarily, but it's extremely common. And I've seen some absolutely horrible lookig rigging that seems to be still doing its job, though I certainly wouldn't leave it that way if it were my boat. From a practical and prudent standpoint, I'd say that 10 years is a reasonable lifespan to expect, and quite possibly more depending on sailing conditions and maintenance, as well as other factors.

Most swage terminals fail from internal corrosion and cracking(particularly the lower terminal ends, which expose the top part of the swage to the weather). Visual inspection can pick up some of these problems, but very fine cracks can be invisible. That's where dye tests come into play, as they highlight the finer cracks. I'm sure a poorly-made swage fitting somewhere has allowed the wire to pull out, but I've not heard directly of such a case from any reliable source.

Dye and ultrasonic testing is far more than most people ever do. If you received satisfactory results here, you're probably OK. But you're really only OK if you yourself feel safe with what's there, test or no test. If the rigging is a year old and you feel better replacing it, then that's what you should do.

You're talking a foreign language to me with a lot of the specific metal phraseology. But that's OK, since one need not be a metalurgist to own or maintain a sailboat, fortunately. There is such a thing as too much information sometimes, and while playing ignorant isn't intelligent either, sometomes it's far more important to approach things from a purely practical, rather than theoretical or scientific, standpoint. In this way one can keep their paranoia in check.

There are so many ways that so many things can fail that to worry about them all will sap the fun from any activity. My advice is to undertake a prudent and pragmatic approach to the maintenance and replacement of boating items, and to do what you feel is necessary to make yourself feel confident about the systems and rigging.

If swage terminals make you nervous, I suggest that you consider rerigging using mechanical terminals--Sta-Lock, Norseman, Hi-Mod, etc. These are as strong as the wire and are field-serviceable. They have an excellent reputation as long as they are installed correctly.

I don't have a problem with swaged terminals from a known quality supplier/rigger, but there's no doubt that some are better than others. There are no guarantees in life, however, so all one can do is choose their rigger carefully, and then upgrade and replace components at their own personal comfort level.

[dmairspotter]

I remember being told that an indicator of hidden problems in swaged stainless rigging terminals was rust on the wire where it enters the fitting.

FWIW, I had the 30 +year old rigging on the Dufour inspected by the local riggers shop and they said it was fine, even though I threw my open checkbook on the counter. I guess age doesn't necessarily mean imminent failure.

Also, on one of my earlier boats I had a forward lower start to fail under well loaded conditions. There was a loud noise, like someone had hit the mast with a sledgehammer. You could feel it through the seat of your pants. It took us about 5 minutes to see the problem. One or two strands of the 1x9 had parted where the entered the top swage fitting. We sailed (gently) home and I replaced the shroud at the dock.

Ever since, Rigging is one of the first things I have inspected on a boat and I always replace if there's any doubt.

On the other hand, the rig stayed up and we didn't all die!

[catamount]

I have never heard of, let alone seen, wire that had pulled out of a properly formed swage. Instead, the failure mode seems to be cracking of the swage due to corrosion and/or embrittlement OR breaking of the wire where it enters the swage due to fatigue (which could especially be a problem if your stays and shrouds are not properly toggled and don't have fair leads).

[Ceasar Choppy]

But I think the hidden corrosion definitely sets the stage for cracking and stress failure of the swage. Its the water running down your wire and getting into the swage and sitting there that causes the corrosion. Mechanical swages are a little different because-- at least on some, so I'm told-- the water can pass through more easily.

If you are still uneasy after all the test you ran, I'd replace it. It shouldn't be that expensive for the size rig you have. The $$ and time you spend testing and re-testing it, could probably buy a good portion of your new standing rigging.

[Scout]

I can tell you first hand that it is not fun to find out your shroud was not properly swaged.

Was dismasted in October of 2004 on Long Island Sound after having replaced the standing rigging in the spring.

The good news was that the rigger stepped up and replaced all rigging and made good on all damage.

A proper swage should last longer than the shroud itself, IMHO.