HerbT,
I see what you are saying--you would cut a hole for the centerboard in the keel shoe. My idea was to just mount a shoe from the nose up to the centerboard hole, then add a second shoe aft of the centerboard back to the rudder. To me that would be a lot simpler and less likely to get epoxy inside the trunk. Also, it leaves a gap for drainage. Each end of each shoe should be properly faired. One other thing is that the bits of shoe left on each side of of the centerboard hole would be mighty thin and serve no real purpose.
Bflat,
I like your idea of not glassing over the shoe and not using fasteners--epoxy is stronger than screws or nails once it has set. Goes back to the sacrificial protection HerbT mentions. Conceivably, if the shoe gets too damaged or worn down, it could be replaced. You could not remove the old shoe since it is epoxied to the keel, but you could plane it down to sound wood, then epoxy a new shoe to that.
This all sounds great in theory, but there is the practical problem of getting at it for replacement. E.g., if you are supporting it with a gantry and slings, the slings go right around the keel shoe, so that would not work. Perhaps you would get it off the boat using a gantry, then support the boat with jacks and remove the slings? Sounds like a pretty major operation I hope I never have to worry about! That's why I like the idea of purpleheart--I'd probably be dead before that wore down much at all.
Also, I don't like the idea of working under a boat that heavy, and how would you hold the new shoe to the old shoe while the epoxy sets? Fasteners would be the only way unless you roll the boat over. (Or maybe duct tape would hold it well enough while the epoxy sets.)
It's starting to look to me, though, like Dynel cloth and graphited epoxy is the best way to go. This would have little or no effect on the the sailing dynamics, while even a slight increase in the height of the keel might.
Maybe the best thing is to just sit in the boat on dry land and pretend to sail it! Or cover it with Saran Wrap. I think my point is obvious--any boat that is used is going to get dinged or worse, that's just the way it goes. But that doesn't mean not to protect the hull as best as we can--it is going to be very difficult to get at the bottom parts for repairs. BTW, I am also looking into epoxy bottom paint. (Will not be leaving the boat in the water between sails.)