Installing GPS pucks without drilling through the deck.
A GPS antenna puck works perfectly well through fiberglass. When I installed mine, I stuck a strip of Dual Lock to the bottom side of my deck and a piece on the top of the puck. I then just snapped the two pieces of Dual Lock together. So far, it has stayed in place. Installed end of 2012. If I need to remove them for some reason, they will easily un-snap.
When I switched from the two puck system to the one puck system, I did not have any holes in my deck. I then mounted the single puck on two angle brackets under the front seat.
I mounted a single puck in a friend's boat in the dash behind the gauges. It worked fine through the fiberglass.