I have the center box like the one pictured and last trip out I noticed is about to come off, thank goodness for the strap attached to it.
There are 2 sets of hinges on the bottom front of the box and 7 of the 12 rivets have come out or broken.
Has anyone ever used ss bolts and locknuts to lock these to the fiberglass? I might try this if I can get to the underneath side from the middle cooler.
Pretty sure rivets are the only option for the hinge side that goes to the box. What size is the question?