My boat originally had a completely open floor with no benches. The mfg used braces to tie the sides to the floor. When I got the boat, most of the screws had either rusted away, vibrated out, or torn through the edges of the braces. After cleaning the boat up, I replaced the braces in the same position but I used rivets instead of screws. I'm not sure if this is the type bracing you're wanting to see but here is what they look like.