The mystery of the Middle Ages dormer cranes – solved!

In earlier blog posts I’ve mentioned that some – but only some – Middle Age villages have cranes on their dormers, like this:

and like this:

The cranes are obviously for hauling loads to the top of the building.

But here’s the mystery: if these cranes are very useful, and indeed they appear to be, then why don’t more Middle Age villages have buildings with such gable-cranes?

I recently learned the answer from a tour guide in Villingen-Schwenningen: ground water!  In the Middle Ages it was preferred to store grain and food underground, in cellars.  But in villages where this was not possible, due to a high ground water table, it was stored on the highest (and architecturally, less useful) part of the building.  Therefore, if you spot a dormer crane it generally means high ground water!