I have a relatively interesting letter concerning these helmets from the producer Bortfeldt. Ersatz collectors might find interesting.
It is made of cork with a “waterproof wool material cover”. This has erroneously been reported as a “gray cotton cover”. The production of the metal items was going to be done locally. It is very welcome substitute helmet was being offered because "the large wartime demand for the fabrication of leather spike helmets cannot be met" We had figured this out but here it is in writing from October 1914! A leather shortage was not caused at this time because of the British blockade. The helmets were offered at eight marks 50 complete. Prewar bulk orders (Wunderlich) seem to have been made for low class helmets at seven marks 80. So it seems that this guy was making a nice little piece from every helmet sold. It also says that they were FOB to the Army Corps. The chin strap was made up of cow skin leather. The claim is that these helmets were lighter, more flexible, and did not shrink nor retain water like the Leather helmets. So shrinkage was a known problem even then.
Based on some other information I now have it seems as though this waterproof was a relatively loose term. Not sure exactly how waterproof the waterproof cover was… As I explore ersatz helmets I am reminded of a government that needs something urgently… if you want it bad you get it bad.
I am starting to feel another article coming along and I was just getting going on the doctrine stuff…