On the night of August 2nd-3rd, 1916, whilst loading ammunition onboard, there was an internal explosion inside the Leonardo da Vinci that killed 248 men. The ship capsized and sank in 11 meters deep water. An inquiry was held, and ultimately, saboutage by the Austrio-Hungarians was blamed for the sinking. Although unstable propellant may have been likely as well. The ship was refloated in 1919. The hull was deemed to be intact and in good condition.
As 1921 was beginning the Caracciolo class was cancelled for economical reasons. Therefore plans were made to rebuild the Leonardo da Vinci, replacing the old 4,7in guns with the 6in guns from the Caracciolo class, and the forward superstructure rebuilt along the lines of the Andrea Doria class, with the fore funnel shortened to the same height as the aft funnel. The Q turret was to be removed, and the space used for 4x3in AA guns. All AA guns except of the ones on the X turret were moved to the sides of the fore and aft conning tower/bridge structure and two fore of the A turret. New propulsion plant would increase the top speed with 1,5kts and four boilers were to be converted into oil firing. The armored deck would be increased to to 5 inches and the magazine to be moved to safer positions.
None of the plans would come to fruition as any plans were killed by the Washington naval treaty.
The moderate proposed rebuild:
There is another design that I will do at a later time, this one kept the Q turret, and removed the B turret instead for a completely different style of superstructure and interestingly, a US-style cage mast.
The article where the drawings and info is based on can be found here:
https://stefsap.wordpress.com/2016/03/0 ... ing-plans/