Fioravanzo commanded one of the 152-mm batteries and distinguished himself, along with a fellow soldier equal in rank named Parona, on 15 and 16 May 1916 in engaging Austrian-Hungarian forces near Duino and hindering their advance towards Monfalcone.
[1] In July Fioravanzo's battery (numbered 97 bis) was transferred near Monfalcone to be deployed against Monte San Michele for use in the planned battle for the conquest of Gorizia.
In 1923, after advancing to senior officer status he took command of the torpedo boat Calliope, an old vessel of the Pegaso class, with which he was sent to the Dodecanese to protect Italian interests threatened by tensions between ethnic Greeks and Turks.
He then served as a subaltern on the newly commissioned cruiser Trieste, and subsequently he assumed command of the destroyer Freccia and of the related 7 torpedo boat squadron.
The School command, in addition to its institutional role of preparing promising ship captains for promotion to higher ranks, also had the secondary task of participating in the control of the Strait of Sicily.
The Department of Special Studies was concerned not only in projects, but also in the rewriting of tactical regulations, of operational statistics, of the writing of articles for magazines and newsletters, and of propaganda (via radio also).
Among Fioravanzo's most important tasks and initiatives it is worth mentioning that in May 1941, he collaborated with Regia Aeronautica Generals Cappa and Mattei to write a series of norms aimed at easing the cooperation between the Navy and the Air Force, until that time very poor, and to create and publish the so-called "blue bulletin" that, every two weeks, updated operational commands on the activity of Italian and British Navy Forces during the previous fortnight; moreover, the Admiral added his own critical remarks to the description of the most significant actions.
This action took place in the wider naval clashed known as the Battle of Mid-June or Operation Harpoon and Fioravanzo participated on orders from Admiral Angelo Iachino, the higher commander at sea.
This brought a negative turn in Fioravanzo's career: due to the anticipated return of the Division without accomplishing the mission, Supermarina (the Regia Marina High Command) decided to leave him ashore and replace him with Admiral Luigi Biancheri.
The mission began on the evening of 6 August 1943 when the Admiral, set sail from Genoa towards La Maddalena (Sardinia) with the Division formed by light cruisers Giuseppe Garibaldi and Emanuele Filiberto Duca d'Aosta.
The sighting by the aerial reconnaissance of unknown ships en route towards 8th Division led Fioravanzo to consider that he was going to clash with an Allied naval force under conditions of sharp inferiority.
Considering the risk of losing two cruisers, but above all the lives of 1,500 crew members without being able to cause significant damage to their opponent, Fioravanzo decided not to complete the mission and sail back to La Spezia although well-aware that this meant the end of his own career.
When the Armistice between Italy and Allied armed forces was signed, Fioravanzo was the military commander of the city of Taranto and offered to replace Admiral Alberto Da Zara, in charge of taking the Italian warships to Malta, in case he could not bring himself to do so.
Today, the wartime setbacks encountered by the Italian Navy and Merchant Marine are credited to Ultra, whose role in the Battle of the Mediterranean was made public in the early 1970s.
In addition to being the director of the Historical Office, Fioravanzo directed the Rivista Marittima (Maritime Magazine) to which he had been contributing since the 1920s with nearly fifty articles on a wide variety of naval-related subjects.
During the 1960s and early 1970s the Historical Office, which he had directed for nearly ten years, published his works dedicated to naval actions in the Mediterranean and to the organization of the Navy in a series of books on the history of Regia Marina (some of them posthumous).