From the Introduction:
Floating well off the shore on a lake is this structure of wooden boards, aluminum girders and thin sheet metal. At a first glance one might mistake it for a dock for small boats when in truth it is a hangar and construction hall for airships. The camouflage paint used on its sheet metal roof even suggests that it is a military structure.
Considering these hints it is no real surprise that the structure is located in the lake and not at its shores closer to a village and city. The volatile gasses providing lift as well as the highly explosive cargo often carried by military airships have given them a bad reputation. Add the fact that these hangars have become priority targets for air raids themselves the inhabitants of the coastal cities and villages sleep a lot better knowing these structures out on the lake, well away from their homes.