Originally Posted by HenkMeuzelaar
Wind Magic, by all means DO go with your own intuition (viz. to use redundant back-up stays or shrouds) rather than to just make everything stronger, as advised by some posters! The relevant failure statistics are pretty straightforward. In short, if you are dealing with a low probability failure event (such as rigging failure) redundancy wins hands down, whereas for high probability failure events upgrading/reinforcing may make more sense.
Here is why: Imagine you have a standard shroud or stay with a .01 (1 in 100) failure probability under a particular shortlasting set of circumstances. By installing gold-plated wire/rod/fittings etc. you would be very lucky indeed to bring that failure probability down by 10-fold (i.e. to .001), simply because even the most carefully manufactured metal component has a finite threshold probability of possessing hidden flaws.... Incidentally, similar threshold phenomena will plague the efficacy of your installation and/or maintenance procedures as well. In other words, it will never become perfect.
On the other hand, by backing that stay or shroud up with an independently attached stay or shroud of equal strength the probability of near-simultaneous failure will basically be reduced by a factor 100 (i.e. to .0001).
This post is thinking what I was feeling, I'm so glad that HenkMeuzelaar was able to put it into words. Relying on one cable as a backstay, for example, is relying on so much. For it all to work the chainplate has to hold, the metal in the cable has to be good, pins, turnbuckle, various nuts and bolts, etc, it all has to work. That is, none of it can have manufacturing defects, be made out of cheap metal, none of it can be suffering from fatigue, be overly stressed, etc, it all has to be right. And in terms of maintenance you HAVE to see the problems when they occur, you have to see strands coming apart, bent pieces of metal, worn pins, etc, and in order for the stay or shroud to be right you even have to see things that cannot be seen! Just because you can't see it during an inspection doesn't mean it can't fail, it's not fair, but life isn't fair, stuff just happens. And beyond all of that a single backstay for example is still a single backstay, a collision can hit it "just right" and break it, or I don't know, all kinds of things, it's a single point of failure. So basically you are putting the security of your mast in the hands of not just one single point of failure, but at least two including the forestay. Maybe if your upper shroud breaks your lower one will still keep the mast up. But depending on a single forestay and a single backstay is rolling the dice and having hopes for the best.
But like Henk said, having a backup with the same characteristics greatly reduces the odds. And it does happen, how many of us know someone who has lost a mast ? How many of us have lost one ourselves ? How many bad storm stories have "dismasted" in them ? I haven't lost a mast, but I feel it is lack of time on a boat that is the reason why, not any particular gift I have for sailing. Odds are very low that a stay will break, I agree with that, and that's great for a sailor who is outside the mouth of the Bay and just starts the motor up and goes back to port to get everything sorted out. But it is a whole different story for someone out in the middle of the Atlantic ocean in a storm, right ? We cruisers will take the performance hit to get somewhere safely and reliably, for a cruiser it's not about how long it takes to get there, it's about getting there safely, so we don't need fin keels and absolutely the perfect sail shape, we just want safety and reliability at a cost we can afford.
I think Mark Matthews expresses the thoughts of everyone with regards to the odds and standing rigging in the opening paragraph of his article here on Sailnet
about standing rigging maintenance. He says ...
Originally Posted by Mark Matthews
If you've ever had the unfortunate experience of watching a rig topple over the side, chances are you are more diligent now when it comes to maintaining the many fittings that keep the mast standing than you once were. And if your sailing experience doesn't include that kind of calamity, you've either been doing something right all along, or the sailing gods have simply opted to keep you in their favor. Regardless, you still might want to avail yourself of some essential tips for keeping your rig in the upright position, without relying too much on the whimsy of fate.
Reading that article you get the understanding of just how critical every little piece of hardware is to that chain of chances that is your backstay. Any little thing could cause it to fail, and there is a reason everyone is so concerned about inspecting it and so diligent about it's maintenance. It's because it's important, and because it's necessary given that each wire is a single point of failure. Because if you don't do it "just right", you could lose your mast. Which would be very bad! It's so critical that I've even read about people X-raying these parts to make sure they are right. Yet, even with good maintenance there is still a chance it could fail, remote, but experience of sailors in general says it can happen. Does it have to ? Or is there something we can do about it ?
I'm mystified by the argument that it's not good practice to have a backup for your standing rigging. Sailors are absolutely nuts about backups and spares, spare GPS, backup for the hull (the lifeboat), redundant means of self-steering, extra parts for same, backup radios, spare tiller handle, ditch bag, backup backup backup. And yet not to backup the very thing that keeps the mast standing upright ? Why ? I mean people even talk about storing a spare handheld GPS receiver in their microwave so that the microwave will act as a Faraday cage to protect the GPS from a lightning strike, many sailors even carry celestial navigation gear in case the whole GPS satellite system suddenly stops working! ... yet we trust that single metal wire that is solely responsible for holding the mast up ?
I wonder if this just isn't another one of those racing things. That maybe all of this came about because many boats were designed to race, and not by design to cruise. I mean was it cruisers who pushed these design decisions, were cruisers lining up at the front door demanding that rigging be made lighter, thinner, with less windage, and no backups or spares ? Why would we care about that ? The only time most of us even mention the word windage is when we are talking about reducing it when at anchor during a hurricane so that we don't drag anchor ...