I'm looking at replacing an old reef line that runs inside the boom. Using the old line to pull the new one through the boom I'm wondering how to connect both without getting stuck (or separate) inside the boom?
I just duct-tapped the two lines together end-to-end really well. You could also stitch them together with heavy thread. I didn't encounter anything tricky inside my boom that might snag or bind. I was surprised by the poor condition of the blocks in there though--maybe worth a look.
I recommend sewing the lines together -- end-to-end -- and also wrapping with tape. You'll have a difficult problem if the lines become separated inside the boom. It's worth the extra time and effort to sew the lines together to make sure that you don't get separation inside the boom.
The mast end fitting of my Kenyon boom has a too-small hole which the reef line must pass through. It is a major pain to get the end through, even without tape. I whip all ends of all of my running rigging, and I usually include a "messenger loop" on each whipping for the purpose of reeving lines. I use 1/8" nylon cord for messengers, which I connect to the messenger loop with a bowline and no tape. Tape adds bulk and stiffness, which can lead to unnecessary jamming of lines at sheaves and tight passages.
Which end of the boom gave you the best access to the internal bits? Jeff, From memory, you probably need to attack it from both ends. The outhaul and topping lift are "anchored" at the front of the boom but do their work at the back. Here's the dis-assembly drawing I made when pulling mine...