Going back to the C/Al mast point - one of my club's Hurricane sailors wrecked his (Al) mast when a shroud managed to escape from the spreader. He had to wait over a year to get a new one as there were no blank sections available anywhere and the company that makes them wouldn't make any until they had orders for (I think) six. If it was a C mast (a) it might have been fixable and (b) he'd have been able to get a replcaement made straight away.