There are four novels in the Prohaska series and they open a window on a lesser-known theater of WWI: the Adriatic sea. The background to the stories is factual and well-researched. The specifics, like those of Conan Doyle's hero of the Napoleonic wars Brigadier Gerard, are entirely fictional.
The first in the series is titled: A Sailor of Austria: In Which, Without Really Intending to, Otto Prohaska Becomes Official War Hero No. 27 of the Hapsburg Empire.
I highly recommend these books, especially if you have an interest in naval history, or European history, or just the World Wars. The humor is a little more scatological and slapstick than the subtle humor of Patrick O'Brian in the Jack Aubrey series, but is nonetheless very engaging. There is, for example, the exploding lavatory, and the camel, a reluctant passenger from Cyrenia to Crete.