..... except that you haven't explained, Jhieminga, how your clue relates to the answer, namely that the Orlogsværftet 'Maagen' III derived from the Danes' modification of the Schreck FBA Type A (Orlogsværftet 'Maagen' II) which used Donnet Lévêque patented designs in its construction (although some sources say the Danes operated Donnet-Lévêque Type As)(see
http://www.natureandtech.com/?cat=38). Or at least I believe that to be the case. The nomenclature of French pre-1919 hydravions verges on the impenetrable!