Italian ironclad Principe di Carignano

Map showing the disposition of the fleets on 20 July

On 16 July, Persano took the Italian fleet out of Ancona, bound for Lissa, where they arrived on the 18th. With them, they brought troop transports carrying 3,000 soldiers; the Italian warships began bombarding the Austrian forts on the island, with the intention of landing the soldiers once the fortresses had been silenced. In response, the Austrian Navy sent the fleet under Tegetthoff to attack the Italian ships.[5] Principe di Carignano was at that time the flagship of Admiral Giovanni Vacca, commander of the 1st Division, along with the ironclads Ancona and Castelfidardo.[6] After arriving off Lissa on the 18th,[2] Persano ordered the 1st Division to bombard the Austrian fortresses protecting the island, but Vacca informed him that his ships' guns could not elevate high enough to hit the high fortifications. Persano then sent Vacca's division to Vis to force the harbor defenses, but by the time they arrived, night was approaching, and so he cancelled the attack.[7]

The next morning, Persano ordered the ironclad Formidabile to enter Vis harbor and attack the Madonna battery, supported by Principe di Carignano and the rest of the 1st Division. Vacca found it impossible to employ his ships in the confined waters, and so he left Formidabile to handle the battery. With the day's attacks again having yielded no results, Persano decided to make another attempt on the 20th. Vacca would take his three ships to patrol to the north-east of the island while the rest of the fleet would again try to land the soldiers. Before the Italians could begin the attack, the dispatch boat Esploratore arrived, bringing news of Tegetthoff's approach. Persano's fleet was in disarray; Vacca's ships were three miles to the northeast from Persano's main force, and three other ironclads were further away to the west. Persano immediately ordered his ships to form up with Vacca's, first in line abreast formation, and then in line ahead formation. Principe di Carignano led the Italian line.[8]

Shortly before the action began, Persano left his flagship, Re d'Italia, and transferred to the turret ship Affondatore, though none of his subordinates on the other ships were aware of the change. They were thus left to fight as individuals without direction. More dangerously, by stopping Re d'Italia, he allowed a significant gap to open up between Vacca's three ships and the rest of the fleet.[9] Principe di Carignano opened fire first at 10:43, at a range of about 1,000 yards (910 m), while the Austrians were approaching the gap.[10] The Italian gunnery was poor, and their initial shooting missed the Austrian ships. Tegetthoff took his fleet through the gap between Vacca's and Persano's ships in an attempt to initiate a melee, though he failed to ram any Italian vessels on the first pass. The Austrians then turned back toward Persano's ships, and took Re d'Italia, San Martino, and the coastal defense ship Palestro under heavy fire.[11] Vacca turned Principe di Carignano and Castelfidardo to port, taking them away from the Austrian ships hammering Persano's division. He briefly attempted to engage the Austrian wooden ships in the rear, but was driven off by heavy fire from three steam frigates.[12]

Principe di Carignano, Castelfidardo, and the coastal defense ship Varese engaged the wooden ship of the line Kaiser, but failed to inflict fatal damage to her before she withdrew. By this time, Re d'Italia had been rammed and sunk, and Palestro had been set on fire, soon to be destroyed by a magazine explosion. Persano broke off the engagement, and though his ships still outnumbered the Austrians, Persano refused to counter-attack with his badly demoralized forces. The Italian fleet began to withdraw, followed by the Austrians; as night began to fall, the opposing fleets disengaged completely, heading for Ancona and Pola, respectively. In the course of the battle, Principe di Carignano had had one of her armor plates shattered by Austrian shells, and one of her guns had exploded.[13] In return, Principe di Carignano hit the Austrian ironclad SMS Drache and killed the ship's commander.[14]

After the battle, Vacca replaced Persano; he was ordered to attack the main Austrian naval base at Pola, but the war ended before the operation could be carried out.[15] The ship's postwar career was limited;[14] rapidly surpassed first by central battery and then turret ships, the first generation of ironclads with traditional broadside quickly became obsolete.[16] In addition, the government lost confidence in the fleet after the defeat at Lissa and drastically reduced the naval budget. The cuts were so severe that the fleet had great difficulty in mobilizing its ironclad squadron to attack the port of Civitavecchia in September 1870, as part of the wars of Italian unification. Instead, the ships were laid up and the sailors conscripted to man them were sent home.[17] Around 1870, the ship's armament was revised to four 8 in guns and sixteen 164 cm guns.[1]

In 1873, the ship was assigned to the 2nd Division of the main Italian fleet; the other vessels of the division were the screw frigates Gaeta and Principe Umberto. Together with the ships of the 1st Division, the entire squadron cruised in the Mediterranean that year.[18] Principe di Carignano was stricken from the naval register in 1875,[1] and was subsequently broken up for scrap between 1877 and 1897.[19] The Navy discarded both of her sisters, along with the ironclad Re di Portogallo between 1875 and 1880 to remove the cost of maintaining them from the naval budget, as part of an effort to reduce the financial impact of the new Duilio and Italia-classes then under construction.[20]