Does anyone know how this piece comes off? It's the backrest at the very back of boat. All the others around the bolt have a fold in the material to get to the screws holding them on. No folds on these pieces.
Open the dog house, stick yer head in there and look for some mounting hardware. It may be a nut and washer on a threaded stud in the backer board for the seat back or a ball stud and spring clamp.