I was curious if Bigfoot put any kind of sealant between the overlapping shell joint. I suspected not, because it would be difficult to do and camper manufacturers don't do "difficult". They are depending on it shedding water - gravity is usually quite reliable after all - but the screw penetrations are many and vulnerable, and don't appear to have been sealed on the ones I have owned. Over time water wicks along the threads and eventually both rots the wood and rusts the screw. Some of the ones I pulled on my '86 were just heads and a bit of decayed shaft left. And as the metal and wood decay, the leakage increases, so its an accelerating process.
One day this summer I may take the time to remove all of mine, dip them in sealant, and replace. It would only take an afternoon with a good drill/driver.
But Bigfoot owners can take heart by reading the thread about repairing the rotting Lance...