The best is to get inside the hull and get a couple of layers bonded directly to the inner glass. If this is not accessable from the inspection port, you can cut away the broken glass and cut a small hole. Sand the inside area. Cut a piece of cardboard that you can insert into the hole, turn sideways and pull down against the inner glass. Before inserting the cardboard, wet out some glass cloth on the cardboard and get a string and a stick. Tie the string to the stick and poke a hole in the center of the cardboard and glass. Pass the line through the hole. (With the stick on the opposite side from the resin wetted glass.) Insert the assembly, turn and pull down with the string to set the glass and cardboard against the inner glass of the hull. When it hardens, you can build up layers of glass on the outside to fill the hole. Finish with a larger piece that will overlap the sides of the hole area.
Director of Parts and Accessory Sales
Hobie Cat USA