I had to change the furling line for my main sail. It was supposed to be as easy as removing the four nuts holding the furling mechanism to the mast, a zspar furling mast. The one problem I encountered was that there was a chafe guard that had been riveted to the mast, protecting the furling line from the sharp edge on the mast. The rivets were made it impossible to remove the furling mechanism so I drilled them out. After pulling out the furling mechanism, I tapped the holes holding the chafe guard to allow a quick line change if needed. One other note is to make sure you hold the main furling "pole" as high as possible and off the furling mechanism, I used a philips head screw driver wedged against the boom to hold up the main furling "pole".