I agree with Dave
My 23.5 used to make a lot of noise too. Nothing done to the halyards would change it. I learned here that it was the cable for the mast head light, and I did exactly what Dave said. Because the spreaders have a bar that goes through the mast, it's hard to feed the pipe insulation all the way from bottom to top. So, I removed the mast foot and head and worked from both ends. It's absolutely quiet now. The best $6.00 I spent on my boat. (Oh, that's not counting the rivets and a rivet tool, so make that $36!)...RickM...