Crack on the side of my trailer

What Dick B said

Quick drill a 1/16 hold just beyond the end of the crack. Be sure to be beyond and not in the crack itself. The hole spreads out the force that is causing the crack. It's easy to fill the hole with epoxy but fixing the crack is priority 1, of course.

Besides fixing the crack I would suggest finding out what caused the crack. We had a crack at the corner of the bedroom slide, traced had it fixed or so we thought, the repair cracked traced it to a broken pin box.