Banging Noise In Mast

[TSAKUS]

We have a 1984 Capital Yachts Newport 33 and when we left the harbor for the long weekend, we noticed that it sounded like there was something banging around inside the mast. This is a new sound on the boat and we found part of a rivet on the deck when we pulled in to our anchorage. I suspect that the conduit (or whatever it is) that runs up inside the mast has broken loose. So my questions are;

1. How do I best go about determining if this is what is going on.
2. What are my options for repairing it?

Thanks for any help you can provide.

[knothead]

Locate the hole where the rivet came from first. If you have a conduit, it's likely that you have pairs of rivets every few feet all the way up the spar. They should be no more than three feet apart, but some people used to think that every six feet was ok. It isn't.
After you find where the rivet came from, it's a simple matter of drilling out it's mate, sticking a hook made from stiff wire into one of the holes and while pulling the conduit against the empty hole, popping another rivet into the conduit.
If they are aluminum rivets, it would be a good idea to replace them all. If they are further apart than three feet, it would be a good idea to add a pair between the ones you have.
Don't let anyone talk you into using stainless rivets for this application. Not necessary.