Kaiserliche Marine, Werft Division - Kiel I
The back of this unused postcard is marked G. Langenschwadt - Kiel-Wik. I have more from the same photographer. It is very likely that it was made during the war.
The sailors are wearing their Matrosenanzug and their Mützenband is marked Werft Division, I can't read the number. Two rare Hirschfanger 1871 bayonets can be seen fixed on Gew71.