My 37 was the same way. It had rust holes all along the bottom half. I sandblasted the inside and out real good to get all the rust and loose junk out then filled it with a liquid steel epoxy type stuff. I can't find the reciept to see just what it was. I not sure but it might of been JB Weld I poured in it. I know I used quite a bit of it, but it sure stiffened up the frame. Joe