Shockwave underside enclosure
You may have accessed the underside by this reply date. I had a leak from the gray tank outlet and had to drop part of the coroplast covering to evaluate and repair. I used an air chisel to cut and remove rivets along crossmember brace and along the sides of the coroplast. Used self-tapping screws and fender washers in the existing holes from the rivets. Also used exterior sealant around small tears in the coroplast. Still holding up after two years.