This design is one of those realized by General Luigi Barberis, commissioned by Admiral Gino Ducci, Regia Marina’s Chief of Staff.
Barberis’ work was group in three set of studies:
- group one, units up to 14.000 tons, 147 to 205 meters length, 3 triple 203 mm. or 3 double 305 mm, 28 to 36 k speed;
- group two, units up to 20.000 tons, 169 to 228 meters length, 2 triple 305 mm. or 4 double 305 mm., 28 to 36 k speed
- group three, units over 26.000 tons.
The P1 design belongs to the group three, all the specs are reported on the drawing.
(Source: Progetti di corazzate per la Regia Marina, Michele Cosentino, Storia militare)