In 1939 the Regia Marina launched a building program aimed to cover operations in the India Ocean. The nucleus for this was the building of a naval base in Chisimaio (very close to the Kenya’s border), and a set of warship specifically designed to operate at that latitude.
Specifically, the program (8 April, 1939) called for:
3 long range cruisers (max 152mm, 8000t);
2 fast oilers, with ability to act as a raiders, 8500t;
12 “oceanic submarines” built for tropical climates (120mm, 1350t);
6 long range DEs, built for tropical climates (max 100mm.);
the program included also, for the Mediterranean:
12 CTs, with double purpose main guns (max 120mm, 1500t);
12 submarines (100mm, 635t).
6 minelayers (1100t)
The very center of the program were the three light cruisers, class later named after the suddenly deceased, prominent fascist politician, Admiral Costanzo Ciano.
The required specs fo such units were as follows:
8000 t., 32k for 12 hours, standard load, 15000nm at 15k (one diesel engine on the central axis, turbines on the others); 6 or 8 152mm, 8 90mm AA, very good horizontal protection, two airplanes, 50% more ammunition load compared to the standards.
A first draft for the cruiser was an unusual ship for the Regia Marina, with two quadruples 152 mm.:
For a long time, it was believed that the Ciano aspect would had been very close to the latest “Garibaldi” class light cruiser, as in the proposed drawing in Warship 2006:
Newer findings of original documentation (reported in Storia Militare) permit a more precise reconstruction of the cruiser aspect (grey areas directly derived from original documentation, other area speculations based on the cruiser design practice of the times):
The specification were:
(Sources: Le implicazioni navali della conquista dell’impero (1935-1941), E. Pellegrini, Ufficio Storico della Marina Militare, Roma 2003; Il programma navale italiano del 1939 (A. de Toro), Storia Militare, November 2013); The Breakout fleet – the oceanic programmes of the Regia Marina 1934-1940, Enrico Cernuschi and Vincent P. O’Hara, Warship 2006))