If you have ever toured the U-505 at Chicago's Museum of Science and Industry or seen the movie Das Boot, you have gained an appreciation of the claustrophobic feeling of submarine service. This 1915 image from Tony Langley's collection is the best I've seen from the Great War at capturing that. Felix Schwormstädt was a German painter who created illustrations during the First World War for the magazine Illustrierte Zeitung.
Schwormstädt was something of a specialist in combat claustrophobia. Here is a similar treatment of the inside of the gondola of a combat zeppelin.