Disaster Only A Whisker Away -January 3, 2002
"Life is full of surprises. Just when you think you have it all figured out, someone pulls the rug out from under your feet. Or, in David's case a few days ago, the whisker stay. One moment he was up at the bow standing on the port whisker stay, reaching to pick up a mooring buoy pennant, and the next moment he was dangling in thin air, fingers desperately clutching the bow rail. Of course, this sort of thing only occurs when you're in a crowded anchorage surrounded by bored boaters looking for a bit of entertainment. As he pulled himself back on board, David gamely tried to convince his amused audience that he had chosen that unlikely moment to do some chin ups off the bow sprit. Just had to burn off some of those Christmas calories. No one seemed to believe him.
Whisker stays, for those of you who are not blessed with a bow sprit, are the two wires (or chains on older boats) that attach to both sides of the bow sprit, providing athwart ship rigidity to the spar. The fitting at the end of the bow sprit to which they and the head stay and bob stay are fastened is called the "cranse iron". After he had collected himself (minus his pride), David inspected our cranse iron and discovered a ragged slot in the two inch wide, quarter inch thick stainless steel plate where the whisker stay's clevis pin had once resided. The steel had simply rotted away.
The scary part is the fact that none of this was obvious. The steel in the immediate vicinity of the hole for the clevis pin was discoloured, but hidden from view by the toggle fitting at the end of the whisker stay. We disassembled the starboard whisker stay and found cracks around the cleavis pin hole on that side of the cranse iron as well. Although the cranse iron is as old as the boat, going on fifteen years, we replaced all of the standing rigging four years ago and should have noticed any pending failures then.
This is a classic case of crevice corrosion, which attacks metal (including "stainless" steel) in tight places where an electrolyte (salt water) is present and air is absent. On the positive side of things, it was timely (though embarrassing) that the fitting failed in a placid anchorage in the Virgin Islands rather than a few days earlier when we were romping along under full sail in the middle of the central Caribbean. Under those conditions, a broken whisker stay could have led to a broken bow sprit and a possible dismissing.
The machinist at a local metal shop seems to think he can effect a fairly simple (and economical) repair by simply cutting the steel plates off short and re-drilling. We've got a couple of inches to spare in the turnbuckle threads on the whisker stays, so hopefully we won't have to replace the wire. The bad part is the fact that it's no simple feat getting the cranse iron off the bow sprit to take into the shop. David spent the whole afternoon removing the remaining stays, our two bow anchor rollers, the pulpit rail, and a few dozen nuts and bolts that are accessible only to someone with x-ray vision and ten inch long fingers - all the time hanging perilously off the bow sprit and cursing at the boaters kicking up big wakes as they whizzed happily through the anchorage.
the pleasures of boating. A great way to start the New Year.
David & Eileen