Rivets
Walter,
I've never had any luck with those hand rivet guns. They usually break after a while and you wind up with boxes of rivets with a tool that don't work anymore. A couple of years ago I had to install a tang on my mast for my new roller furler and I brought my boat down to Rudy at D&R Marine in Assonet to have him rivet it on with his pneumatic rivet gun. I had drilled the holes for the tang myself, but for something such as a fore stay which carries a lot of tension, I didn't want to take a chance on my DIY skills. With that said, I've drilled holes and tapped my mast for small machine bolts to hold cleats, and they have always held all right. It's probably a good idea to use Lock-Tite on the threads to keep the screws from vibrating out. Another type of fastener that I've used that was pretty good and only required a hammer to install them is a star rivet, or Stop Rivet. These are simple to install and they hold very well. The old rivets can be drilled out in most cases and new ones installed. Here's a site that illustrates how the Stop Rivets work. Good luck.
Joe