I had a look at Elemer Malanotti's entries in the “Rangliste der K.u.K. Kriegsmarine.” It’s strange. He's a Fregattenleutnant throughout the war — and the senior Fregattenleutnant for much of the war. Which is to say for some reason which is not obvious in the Rangliste he wasn’t promoted to to Linenschiffleutnant in November 1915 with his classmates. Most of the officers that didn’t get promoted were either POWs (kriegsgefangen) or missing (vermißt). Malanotti isn't listed as either of those.

Malanotti is though shown as having passed both the submarine and torpedo courses.

The German UB 3 is a complete red hearing in this — the small UBI submarine was only ordered in November 1914.

My guess is that the boat you’re referring to is the Austrian U 3 (also written using Roman numerals as U III), which was sunk on August 13, 1915 with a portion of the crew killed and a portion captured by the Italians. Perhaps was Malanotti was captured at that point and the Rangliste is just wrong in not including a "kriegsgefangen" notation.

As for the October 17, 1914 action, the Austrian U 3 and U 4 operating out of Cattaro attempted to attack the French armored cruiser Waldeck-Rousseau on that date. U 3 managed to obtain a good firing position but her periscope was spotted and fired upon.

I have no idea about Austrian naval personnel records.