Italy already possesses a plausible starting design in Ettore Fieramosca with four bow tubes, four stern tubes, and fourteen torpedoes. The boat was over-dimensioned for her armament, missed her intended 20-knot surface speed by about five knots, and lacked the desired endurance. Because she came in well below the 2,800-ton ceiling, an enlarged successor could correct those weaknesses. Such a boat offers limited value inside the confined Mediterranean but becomes dangerous when based from African colonies for operations in the Indian Ocean or North Atlantic.
Chapter · 41:54-43:43
Italy must choose between Mediterranean and oceanic cruiser submarines
Fieramosca offers Italy a lightly loaded starting point, but a larger successor makes most sense from colonial bases in the Indian Ocean or Atlantic.