In the nineties, there was a brief interest in resurrecting transport operation of modern airships, and in the vast new polders in The Netherlands, a factory and landing or mooring field (600 m in circumference) was planned. Design had started, and I was intrigued by one of the problems the designers encountered in the certification: micro climatic effects on the long (300m +) length of such airships. Especially the effect of icing or even rain on one end of the ship needed to be countered relative to the clean other side of the ship. Ice can be very heavy on such a scale. I believe there was even a joint effort (Anglo-Dutch) to propose certification rules for transport airships.