Walking the Mast

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The nut had been working loose for months. In daysails on Puget Sound, every tack had jogged it just a bit, made it move just a fraction of a turn. In all likelihood, infinitesimally minute rotation also occurred with every little back-and-forth roll as the vessel sat at its slip in the marina. Very slight, very slow, but there are only so many threads in a nut.

This particular nut was on one end of a throughbolt in the mast of a cruising cutter that we had rerigged, working with the owner, over the course of several months. It was a thorough upgrade – standing rigging, running rigging, winches, chainplates, the works – with dozens of new components, every one of which is crucial to the well-being of a proper rig. Sure, there was redundancy everywhere, in factors of safety, distribution of load, multiple backups, or all of the above. But redundancy in a cruising rig is just another way of saying that the odds of survival Out There are a little better than they might be. One can't really ever afford to lose any of one's margin; help is usually too far away.

Some see this component-based opportunity for catastrophe as a fundamental flaw of conventionally stayed rigs. The old jeremiad goes that, "lose one component, one cotter pin or one clevis pin, and the whole rig goes over the side". But I have always believed that this description is back-side-to; the way to keep the rig in the boat is to install good components, in a good design, and then to keep track of those components. Or as Mark Twain put it, "Put all your eggs in one basket, and then watch that basket." Besides, a good cruising rig might not have the deepest possible redundancy (wouldn't it be nice to carry a spare mast, the way a car carries a spare tire?), but there is usually enough in reserve that the loss of one component, however critical, doesn't mean the loss of the entire rig.

Such was the case when the nut finally came off the bolt that held the lower shrouds to the cutter's mast. This was about 40 miles off the coast of Northern California, in a disturbed seaway, in a good breeze. The throughbolt leapt unrestrained out of the mast, and both sets of lower shrouds fell to deck. The fore-and-aft stiffness of the mast was not directly affected, but the unsupported lateral length instantly doubled, which instantly made the mast four times less stiff, four times less able to handle the compression loads imposed by the uppers shrouds, forestay, jibstay, and backstay. Four times more likely to deflect and collapse. And it was a near thing: the mast whipped back and forth in a blur, like a living thing, and a living thing in pain, at that. The crew saw this and knew, without a doubt, that it must come down, that it could not stand. But somehow it did, and they set about doing what they could to keep it standing until they could get to a safe harbor. The details of this part of the adventure are for another time; what matters here is why the nut came off that bolt in the first place.

We have a ritual, called "walking the mast." It is the last thing we do before the crane comes, and it is as much a valediction as a last chance to catch any flaws. You see, the mast is at the heart of what we do. It is the focal point of the sails, running rigging, standing rigging, and, I think, the hull itself. It is that relative to which all our work is oriented. So we don't walk the rig, we walk the mast. Further, we are blessed in that our work is not, ever, a purely mechanical process. For one thing, the people we get to work with tend to extraordinarily good company. As a group, cruising sailors or some of the finest, funniest people on the planet. For another thing, sailboats – and especially sailboat rigging – are beautiful things. What a pleasure it is to work on a system that comprises exquisite machine-made parts, satisfying handwork, and the pure expression of mathematical ideals. And finally, how wonderful to do something that matters. Yes, sailboats are toys, are far from essential to the workings of the mundane world. But our people take them to far-off places, where our good work is as important as the skill and resourcefulness of the crew. How gratifying it is to be part of that adventure.

So when we walk the mast we do so carefully, even if it means keeping the crane waiting, even if the travel lift is waiting behind the crane. We check everything once more, as much for blessing as for quality control.

I have been doing this, on countless masts, for almost twenty-five years. In that time, it was inevitable that I might miss some details, bless a rig that was less-than-optimum. Partly this was because of ignorance; no matter how intently one studies, and how rapidly one learns, the subject of cruising vessel rigging is a vast one, and not easily mastered. I know that, even now, I grimace at some of the things that, years ago, I placed a mistaken faith in. But partly, missing things is a matter of odds; no matter how careful one is, nor how aware of the consequences to oneself and others, it seems inevitable that details will slip by. The irony here is that this particular detail was one that we were in the habit of checking most carefully of all.

As noted above, a stayed rig is a series of components, every one of which is inspectable, every one of which can be installed, removed, and replaced by human beings. This is the strength of the system, the overwhelming upside to the vulnerability to failure that each component represents. All we have to do is look, and the odds of anything failing go towards zero. And field experience bears this out, since it is nearly always vessels that are neglected, or indifferently assembled and/or designed, that experience rig problems. Nevertheless, every component is, indeed, a potential trouble spot, and some of them have a higher potential for trouble than others. Offhand, I can't think of a more critical component than a lower shroud throughbolt, which is why we are downright obsessive about the dimensions and quality of said bolts, and why we always, always see to it that the nuts which hold these bolts in place are secured, at the very least, by Nylock liners, and preferably by Loctite, and frequently also by a light peening of the bolt ends. The idea is to have a nut which cannot possibly come off by itself, but which can be removed with tools, for maintenance or other reasons. So there was definitely a Lone-Ranger-shot-with-silver-bullet feeling in the shop when the word came that, apparently, no such measures had been taken in this case.

The boat now sits in a harbor in Northern California. The mast was significantly damaged in the incident, and will be replaced. We and the owner now wait on a glacially slow insurance company bureaucracy. It is possible, of course, that someone unthinkingly removed those tangs for some reason, after we were done with them, and put them back on without securing them. I would like to believe that. But we still walked that mast, and did not check that one detail. Why should we have? We always make sure of those nuts. Right? Maybe not. "Sometimes", as on old Mainer once told me, "the best is none too good." Chastened, reminded of our limitations, we walk masts a little slower still.