Two thoughts
1. This is the "opportunity" you've been waiting for to replace the main halyard.2. This is what money is for: get your local rigger to go aloft, remove the old halyard and reeve your new one in place. And, at most yards, this is not expensive.Finally, do you know how many people have been seriously injured not going aloft, but going aground once they were aloft? If you have any doubts about either your ability or your equipment, don't do it. Hire a pro. That's what they get paid for.Many years ago, I was between boats so I chartered a lot. On one boat on a windy day I reminded my wife to clip the main halyard on the life lines after taking down the main....right. She dropped it up the mast it went. Luckily, we were near a marina and so we motored over there. We explained the problem to the yard manager who promptly sent two kids over with a bosuns chair. Up one went, down came the halyard, and they were done in less than 10 minutes. The cost? They guiltily asked for $15 (they were being paid $7.50 an hour). We gave them a $20 and were on our way....