ACMO rigging - unusual failure

Craig Briggs

We keep our 1992 SN "Sangaris" at the dock in front of our condo in Delray Beach, FL, where she's been in her slip for two years, what with Covid and other issues preventing active cruising. Today, Katherine and I were walking to the boat at mid-day to continue readying her for our planned summer cruising (finally!).

Incredibly, as we walked up to the boat along the dock we heard an explosive "bang" and actually saw the starboard mizzen backstay break at the top of the lower swage and proceed to whip across the deck. An amazing coincidence. We went aboard and easily contained it, but what a shock. The rigging was new in 2010.  Had we not actually seen it break we would have been totally at a loss to understand what had happened. Clearly, just sitting at the dock with gentle rocking had been weakening that stay.  

We had, indeed,  observed a concerning amount of rust just above the lower swaged fittings (mostly on the mizzen stays) but dismissed it as inconsequential. That being said, in 2009 the aft lower mizzen stay blew up under load at the lower swage while we were power reaching at 8+ kts with four sails off Catania, Italy, and that is what motivated us to replace all the rigging in 2010. ACOM provided the new rigging for about $5000 US and we installed it ourselves. 

Our plan now is to replace all the rigging and use mechanical fittings, rather than swages. But to have a stay "blow up" at the dock while you are walking by seems pretty bizarre - good thing we were not on passage.
All experiential input from fellow owners, of course, would be appreciated.

Cheers, Craig
SN68 Sangaris, Tropic Isle Harbor, FL

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