I\\\'ve seen this happen on another boat within 24 hours of being launched. I mouse my shackles with a little cable tie going through the hole in the pin. Do the same with the shackles up at the top of the shrouds as well, because you can\\\'t check them when it is up. (Who ever thought that a good word to describe wiring up a shackle would be mouse?)

I had to talk someone out of bolting a tabernacle to a cabin top with huge through-the-roof bolts, so it could \\\"hold the mast up if the shrouds fail\\\". You really want quite weak bolts/screws so they pull out and cause as little damage as possible, not rip the roof off.

Hope you are soon fixed and back on the water.

This was a case of the bottom shackle pin(s) coming loose - the shrouds themselves were fine.

Julian

At risk of being labelled a pedant (as well as being that junk rig nutter), I think, strictly speaking, that you don\\\'t mouse a shackle pin (I\\\'m not sure what you do to it - \\\'wire it\\\' sounds OK if a bit \\\'modern\\\'). You mouse a rigging hook (which I guess is an obsolete bit of tackle anyway), closing the hook off so that nothing can slip out of it. Strictly speaking, nothing to do with ensuring something doesn\\\'t work loose. Unless nautical usage has changed, which it might have.

More pedantry - I believe \\\'to mouse\\\' (as a verb) was pronounced \\\'mouze\\\' by genuine jack tars. I\\\'m looking into it. On the principle that a treenail should always be a trunnel, for auld lang syne. Anyone interested? - no? - not to worry!

Some years ago, the mast of my Heron dinghy went over the side, with damage to the mast step, when a shackle pin, which I ALWAYS checked to be finger tight before sailing, worked loose. Claus is probably right - pliers or shackle key: but even then I would want to check quite frequently. Most of the shackles I have to do with, don\\\'t have a hole in the pin-head anyway, so how would you wire (or whatever) those? That, incidentally, is why I\\\'ve gone for unstayed rigs - only joking, but it is one less thing to be checking.

I lash my shrouds to a shackle in the chain plates with a lanyard to make it easier to rig and de-rig the mast. Once everything is set up properly, if I have to take the mast off, I just have to undo the shackles. Putting the mast back on, just redo the shackles and the lanyards are still the correct length. If you have to undo the lanyards, then it takes a while to get shroud tension etc. right again.
Regarding lanyard wear. I check mine everytime I go sailing, and they don\\\'t seem to be wearing at all. I wouldn\\\'t really expect them to because any movement is between the shackle and the chain plate. There is very little movement between lanyard and shackle. I replaced the bottle screw on the forestay with a similar lanyard halfway through last season because the screw kept working loose. The lanyard doesn\\\'t.