How are the tangs for the upper shrouds (and lower for that matter) attached to the mast on the Cherubini Hunters? There is a tube that goes through the mast, I'm assuming to prevent the mast from crushing when the bolt holding the tangs is tightened, but there is an insert on each side that goes through the tangs and into the mast tube - the bolt then goes through these inserts and into the tube. I managed to get one side out, but the other side won't come out - are these inserts (like a collar of sorts) physically attached ti\o the tube on one side?