Spontaneous Shroud Detensioning

I've never heard of this happening before--have you?

I sailed out to Catalina yesterday, which is about 3.5 hours from my slip in San Pedro, with a good breeze. After mooring for the night and having a couple drinks, I walked to the bow to relieve myself. I grabbed the aft short shroud for support, and nearly fell overboard I was so startled! The shroud was so loose, it was actually blowing in the breeze, and probably had 6 inches lateral play.

Initially, my heart sank as I thought something had broken or shifted. But in the morning daylight, everything seemed to be fine. I inspected the turnbuckle, and I could tell that it had backed itself off, because of the coloration of the stainless steel.

I recently bought the boat (3 months), and I have not yet tuned the rig. However, all shouds have always been tight (and I'm certain this one was the morning we left). And, I never imagined a turnbuckle would spontaneously undo itself. Does that happen?

For what it's worth, it was blowing 20-25 yesterday, and my old worn-out jib no longer has a leech line. The damn thing was flogging something fierce, and that had the whole boat shivering. Could that have done it? If so, why only one shroud?

Followup

Also, I suppose it's relevant that the loose shroud was leeward the entire trip, and the wind was about 40 degrees off our bow. I'm guessing the wind would have been tending to push the mast back toward that shroud, thereby lessening it's tension compared to the others--but wouldn't that be a slight effect?

Absolutely. We did an overnight race on my friend's Sabre 362 that was about 60nm. The lower lee shroud had loosened to the point of almost parting at the turnbuckle. My friend never uses pins. I told him he was nuts. Good thing it was the same leg the whole way. I don't like to think about what could have happened if we tacked late in the race.

They'll definitely loosen while sailing. Especially the lower shrouds on the leeward side. It's imperative to lock your turnbuckles with line, a ring, or a screw, etc.

Thanks, guys. I'm reassured. I'll look into locking the turnbuckles now.

velcro thingies

take a look at those velcro pin thingies that Layline has. They should be in their "cool new stuff" area. Easy to adjust the rig, no tape, all around good idea.
Chris

That's what happened

You MUST secure the Turnbuckles or the will come loose when unloaded and moving around-
When you re-tune, remember the aft lowers should be looser than the fwd lowers! See previous posts on this topic!

Cheers,
S