The deck armor was increased during the reconstruction to a total of over the engine and boiler rooms and over the magazines, although its distribution over three decks, meant that it was considerably less effective than a single plate of the same thickness. The armor protecting the barbettes was reinforced with plates. All this armor weighed a total of . The existing underwater protection was replaced by the Pugliese torpedo defense system that consisted of a large cylinder surrounded by fuel oil or water that was intended to absorb the blast of a torpedo warhead. It lacked, however, enough depth to be fully effective against contemporary torpedoes. A major problem of the reconstruction was that the ship's increased draft meant that their waterline armor belt was almost completely submerged with any significant load.