Rivets and there are some machine screws with nylock nuts that hold the hull to the cap on the outer perimeter. They are also glassed together I believe through the floor and compartments. The boat isnt gonna come apart thats for sure. I would think you need to contact your dealer and they should get this taken care of for you. If you want to handle it yourself I would contact basscat and they can get you the rivets as they are a hard to find special piece. I would recommend a pneumatic rivet gun from harbor freight.
.
