General (naval engineers) Ferrati, based at La Spezia arsenal, was the designer of the first fast battleship class, the four RN Caracciolo. At the USMM (Italian Navy Historic Office) are stored a set of 9 follows on, in three groups, F, D and G, all based on quadruples 381 turrets.
These project can be seen as responses to the current French naval designs (Normandie, Lyon, Gille, Durand A and B).
The F group is the lighter one, based on two quadruples 381 towers. F and F’ differed only in speed:
27300t, 200m length, 8 381/40 (2*4), 16 170/50 (8*2), 24 102/50, 8 533mm TT, 55000/75000 HP for a 25/27k, armor 270 mm for 2/3 of the ship length, and a reduced height up to the bow and the first rudder.
31300t, 210m, 95000/115000 HP for 29/31k, identical to F design for the rest.
(Source: Bollettino d’Archivio, Dic. 1988, A Rastrelli)