instead of P.A.K, could it not be B.A.K Schule?
around that time the Marine Fesselballon Abteilung was at Bredene and Stene, there was also a Luftschiffer Abteilung of the army detached to the Marinekorps, but the leading officer was hauptmann Stein.
In the Kapellestraat was the Marineheim.