J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Anchoring Shrouds in Spreader Tips?

I'm rigging the mast for the first time.

The spreader tips have fairly shallow sockets for the upper shrouds to sit in where they pass over the spreader. How are the shrouds supposed to stay anchored in those sockets when the mast is going up and the shrouds are hanging loose? What about if a leward shroud goes slack when sailing? It would be all over on the next tack. Am I missing a crucial piece of equipment?

Thanks for the help.