I was recently hanging out with a friend of mine who makes high-tech kayaks. In our discussion of dream boat designs, my friend mentioned that carbon fiber and aluminum are +/- electrical potential and therefore create a nice battery that dissolves the material around both sides of the connection. He explained how someone brought him a 5K carbon bicycle where the paint on the aluminum came off and the frame dissolved along with the aluminum. This last weekend, we went to fix a carbon rudder housing + carbon tiller arm on one of our A-cats. The old aluminum rivets showed excessive corrosion, but after drilling them out, it was clear the carbon holes were enlarged with lots of corrosion signs. We had to repair it with a stainless sleeve and stainless rivets. In talking with sailors, I am suprised how few people know about this. To recap, this seems to be the basics. Perhaps some real engineers can correct any errors:

Fiberglass + Alum/Stainless/Carbon> ok, watch for tearing
CarbonFiber + Alum> NO-- significant electrical reaction
CarbonFiber + Stainess/Fiberglass> ok
Aluminum + Stainless> materials will electrically bond (so you cannot remove screws), but no structural risk