Several designs were proposed, including options for a so-called "yacht cruiser" that was to have been used by Archduke Franz Ferdinand, the heir to the Austro-Hungarian throne.
The design that was ultimately selected called for ships that were capable of speeds of at least 30 knots (56 km/h; 35 mph), with an armament of fourteen 12-centimeter (4.7 in) guns and a thin armored belt that was 20 millimeters (0.79 in) thick.
The Ersatz Zenta-class cruisers were intended to be constructed at a time when Austro-Hungary was engaged in a naval arms race with its nominal ally, Italy.
[1] Italy's Regia Marina was considered the most-important naval power in the region which Austria-Hungary measured itself against, often unfavorably.
These conflicts provided the background for a major naval expansion program in Austria-Hungary, which received broad support in the Austrian and Hungarian parliaments.
Admiral Anton Haus, then the Commanders-in-Chief of the Navy (German: Marinekommandant) used the growing risk of war with Austria-Hungary's nominal ally, Italy, to push his construction program.
In either case, the maximum speed for the so-called "yacht cruiser" was to be 24 knots (44 km/h; 28 mph), with no armor protection, and it was to resemble the other two ships as closely as possible.
Fiala submitted two variants, Ia and IIb, along with a third for the "yacht cruiser" that was considered separately during the design competition.
His third design, Ic, was identical in dimensions to the other two proposals, though it incorporated an armored belt of 60-millimeter (2.4 in) Krupp cemented steel.
[13][14][c] On 16 May, the navy informed the shipbuilding firms Stabilimento Tecnico Triestino (STT), Ganz-Danubius, CNT Monfalcone, and San Rocco AG to submit tenders to build the ships, with a deadline of 5 July.
At the same time, Fiala issued a request for a 40,000 shp (30,000 kW) propulsion system to STT, Ganz-Danubius, and Breitfeld & Danek.
On 2 August, days after the outbreak of World War I, the navy awarded Ganz-Danubius with the contract to build the three cruisers.
Again, the navy chose Fiala's proposal, named IIb, as the basis for the "yacht cruiser", citing its heavier armament and higher speed, compared to Morin's vessel.
But no final design had been approved by the time Franz Ferdinand was assassinated in Sarajevo on 28 June 1914; with the death of the man who had requested the "yacht cruiser", the navy no longer had a reason to pursue the project.
[6][16] The 12 cm guns had reached the prototype stage only by the outbreak of World War I saw the ships' cancellation, so no performance data exists.
[19] With the assassination of Archduke Franz Ferdinand on 28 June 1914 however, construction on the first ship was halted just days before its hull was scheduled to be laid down.
The navy mistakenly assumed no new projects could be completed before the war would be over, and any wartime experience would necessarily have to be incorporated in any future design.
[15][20] In August 1914, the Austro-Hungarian government suspended all contracts which had been awarded as part of Haus' naval program, including the three ships of the Ersatz Zenta class.
[21] Instead, in late 1914, a scale model of the design was taken to the Tiergarten in Berlin, where the Königlichen Versuchsanstalt für Wasserbau und Schiffbau [de] (Royal Research Institute for Hydraulic Engineering and Shipbuilding) had testing facilities, since the Austro-Hungarian Navy had no such capability.
[15] The new project was simply a design study only, since the majority of the shipyard workers had already been drafted into the Austro-Hungarian Army and material shortages prevented any actual work from being done anyway.