The Uncertainty of Stainless Steel

We’re here in Niue and have been thoroughly enjoying ourselves for the last month or so, meandering West in a zig-zag pattern in the general direction of Tonga. It’s been exclusively down-wind sailing since we left Rarotonga. In fact, the mainsail had stayed in the bag on the boom for the entirety of that period until we decided to set it for the final few hours of our passage from Beveridge to Niue, mostly to give it an airing but also to provide some stability while we flew the spinnaker. Bob rolls with a sharp, fast motion and it seems I’m the only one who doesn’t mind it too much. Sarah is not a fan of rolling and it seems that Bob isn’t either. We have suffered our second major rigging failure in as many months, while moored in the Bay at Niue.

 

This 5/8″ T-bar appears to have suffered a fatigue failure just as the sta-lock fitting failed a couple of months ago. Sarah and I were on shore and arrived back to Bob after dark to be greeted by the sound of something banging against the mast. At first I thought it must be a halyard that I had neglected to secure properly, but we were both dismayed (to say the least) to discover that it was in fact our Starboard lower shroud – the other end of the same shroud that failed en-route to Raiatea.

Now, one failure of a 2 1/2 year-old fitting could be put down to very bad luck. Two failures implies a very serious problem with the design of the rig. I have always had my doubts about it but figured it would be OK since it has been so for the past 40 years with no particular problems. Mind you, none of these boats, to my knowledge, has ever travelled so far as Bob. And then, most are probably no longer sporting their original 1970’s masts. Only a single set of spreaders and a single set of lower shrouds. A baby stay, intermediate shrouds and running backstays help to stabilise things but it was never going to be great on account of the fact that not only are the chainplates set forward of the mast (so all of the shrouds serve to pull the mast slightly forward instead of the usual aft, or directly out to the side) but the builder didn’t even put them equidistant from the mast, which means the shroud tensions are by necessity unequal. Not ideal. Between the mass of the mast flopping back and forth with every roll and probably some flex in the hull moving the chain plates themselves by a tiny amount, the shrouds load and unload repeatedly, not just at sea but in any rolly anchorage. Unfortunately the only thing that I have any control over at present is the shroud tensions. It is possible that I had them a touch tight (though still nowhere near the ’15-20% of the breaking strain of the wire’ that is apparently officially recommended for shroud tension) so I’ll back off on that a little. We now find ourselves hoping we can make it to New Zealand with the current setup so that it can be completely re-designed and re-built there. I’m thinking of two additional chain plates on the outside of the hull, one forward and one aft for split lower shrouds. We will also look very closely at the feasibility of installing ‘soft’ (non-wire) standing rigging, depending on price, the danger of chafe and it’s resistance to fatigue failures of the sort that Bob’s rigging appears to be prone to. For now, Larry and Sue from s/v Serengeti have given us their spare second-hand T-bar fitting so we should be back in business shortly. If these swells from the SW ever die down and we stop rolling violently back and forth I’ll go aloft and make a close inspection of all the stainless fittings. I’ll also install dyneema straps as backups around as many fittings as possible so that if another one goes while we’re sailing at least we’ll hopefully save the mast.

 

Until the rig looked like it might fall down, the most pressing maintenance issue was a duff VHF aerial. We’d noticed that our VHF range and AIS reception range had plummeted from about 25 miles to about 4. With the help of some advice from Yahav (s/v Cheeky Monkey) and Larry (s/v Serengeti) I was able to diagnose the aerial itself as being the problem component, and, since there was nothing to lose from a non-expert bodge (and no hope of getting a new one for some time yet) I figured I might as well take it to pieces and see if it was salvageable. Unfortunately I didn’t think to take pictures for the blog while I was in the process of butchering it but I can tell interested parties that VHF aerials are actually fairly simple affairs. Some water had managed to get into ours through a tiny crack in the plastic housing at the top (cracked due to relentless UV exposure) and, I think, broken a capacitor which appears to be the only electronic component in the whole thing. I removed the capacitor, soldered a few things to a few other things that may or may not be supposed to be soldered together, patched up all the holes that I’d drilled and/or pried in the housing and stuck it back together with the liberal application of duct tape, hose clamps and sikaflex sealant. It remains to be seen whether this mess constitutes an improvement or an effective destruction of our fixed radio apparatus. We shall see! In the meantime here’s a picture of the result:

 

 

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