Another thread a few weeks ago brought up an often overlooked factor: the glassed-in wood shelf that supports the front of the bunk. It, not the hinge, carries the
weight. It was noted that undetected or neglected
leaks in the window can cause the wood to rot inside the
fiberglass.
I'm unable to find/post that link right now, but it did have some good ideas re strengthening the bunk set-up. If you use the Google search for "Scamp bunk" it should show up.