Caio Duilio was the lead ship

Lead ship

The lead ship or class leader is the first of a series or class of ships all constructed according to the same general design. The term is applicable military ships and larger civilian craft.-Overview:...

 in a class of two ironclad battleships built in Italy for the Regia Marina

Regia Marina

The Regia Marina dates from the proclamation of the Kingdom of Italy in 1861 after Italian unification...

in the 1870s. A revolutionary design fitted with the largest guns available, 100-ton 450 mm calibre muzzle-loading guns, she and her sister ship

Italian ironclad Enrico Dandolo

Enrico Dandolo was an ironclad battleship built in Italy for the Regia Marina in the 1870s. Designed by Benedetto Brin, together with her sister ship , and armed with 100-ton, 450 mm muzzle-loading Armstrong guns, she was considered the most powerful battleship of the time...

 were regarded as the most powerful warships afloat in their day.

On March 1873, Italian minister of the navy Admiral Simone Arturo Saint-Bon

Simone Arturo Saint-Bon

Simone Arturo Pecoret de Saint-Bon was an Italian admiral.Saint-Bon was born at Chambéry, now in France, then part of the Kingdom of Sardinia....

 announced the construction of three new battleships for the Regia Marina, which would be the most powerful in the world. The naval architect Benedetto Brin

Benedetto Brin

Benedetto Brin was an Italian naval administrator and politician.-Biography:Born in Turin, he worked with distinction as a naval engineer until the age of forty. In 1873, Admiral Simone Arturo Saint-Bon, Italy's Naval Minister, appointed him undersecretary of state...

 was asked to design them. The first to be launched was Caio Duilio, named after the Roman Consul Gaius Duilius

Gaius Duilius

Gaius Duilius was a Roman politician and admiral involved in the First Punic War.Not much is known about his family background or early career, since he was a novus homo, meaning not belonging to a traditional family of Roman aristocrats. He managed, nevertheless, to be elected consul for the year...

. Constructing these ships greatly stretched the infant Italian ship industry but, at the same time, helped the country to develop towards a modern industrial economy. Only two ships were constructed.

Design

In her day the Caio Duilio was as revolutionary in her design as the French had been a decade before. The ship exemplified the concept of the 'monster gun', a vessel carrying the heaviest calibre weapons possible, capable of incapacitating an enemy warship with a single hit.

Initially designed to carry four 38-ton rifled muzzle loaders, similar to those carried on the British the design was sufficiently flexible to permit the gun calibre to be increased during construction. When the British armaments manufacturer Armstrongs

Armstrong Whitworth

Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. Headquartered in Elswick, Newcastle upon Tyne, Armstrong Whitworth engaged in the construction of armaments, ships, locomotives, automobiles, and aircraft.-History:In 1847,...

 announced their 50-ton 355 mm RML (rifled muzzle loader), Duilio was modified to receive it instead, which required considerable modifications to the ship's armour to save the necessary weight. Eventually the gun calibre was increased to accept an even newer and larger Armstrong gun, the 100-ton 450 mm RML.

To accommodate such massive weapons, the armour belt was restricted to the central third of the vessel, forming a citadel on which the turrets were mounted en-echelon (forward turret to starboard). This arrangement enabled all guns to bear on either beam, but end-on fire was compromised by the severity of the muzzle blast causing damage to the ship's unarmoured upperworks.

Either end of the ship, outside the citadel, was subdivided into watertight compartments, so that flooding due to damage to the ends would be contained, and would be insufficient to compromise stability.
Weight of armour and armament precluded auxiliary sail propulsion, which for the limited range required to operate in the Mediterranean, was in any case unnecessary. The ship was a mastless design. The design speed of 15 knots was high for a battleship of this era, but there was insufficient space within the citadel to accommodate all the machinery. The boilers and engine spaces were protected by an armoured deck 50 mm thick extending the full length of the waterline. This protection scheme was described as a 'raft-body' design.

The compromises in protection, and general structural weakness, raise doubts as to whether the large guns could keep firing across the deck. The unarmoured ends were vulnerable to rapid firing light weapons, and could conceivably flood sufficiently to cause her to turn turtle without penetrating the thick armour at all.

These perceived limitations were probably overstated for ships designed to operate in the sheltered waters of the Mediterranean.

Accident

In 1880 a gun of the Duilio fractured due use of very coarse prismatic powder (Fossano powder more precisely) which subjected the gun to pressure irregularities. Thereafter charges were reduced in the Italian Navy, and the British followed suit.

British response

The ship was widely regarded as the most powerful of her day, inspiring the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

, the largest in the world at the time, to respond with , intended as a direct counter to the Caio Duilio and her sister ship . The Royal Navy perceived the growing Regia Marina as a potential threat both to its territories and bases in the Mediterranean and to its trade route through the Suez Canal

Suez Canal

The Suez Canal , also known by the nickname "The Highway to India", is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea and the Red Sea. Opened in November 1869 after 10 years of construction work, it allows water transportation between Europe and Asia without navigation...

 to India. Inflexible was conceptually very similar to the Italian ships, and attracted the same controversy. However, Inflexible was originally designed with 60-ton guns, to outgun the Italian ships' original 35-ton guns.

However it was not possible to increase the size of the British ship's guns to keep up with those of the Italian ships; and Inflexible was completed with 81-ton 16 inch (406 mm) guns. As a further measure, however, the British government installed two of Armstrong's 100-ton 450 mm guns in Gibraltar

Gibraltar

Gibraltar is a British overseas territory located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean. A peninsula with an area of , it has a northern border with Andalusia, Spain. The Rock of Gibraltar is the major landmark of the region...

 and another two in Malta

Malta

Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

. One gun of each of these pairs has survived to the present. In Gibraltar the British mounted one gun in Victoria Battery (1879) and the other in Napier of Magdala Battery

Napier of Magdala Battery

Napier of Magdala Battery is a coastal battery on the south-western cliffs of the British overseas territory of Gibraltar, overlooking the Bay of Gibraltar near Rosia Bay.-History:...

 (1883); the gun in Malta is at Fort Rinella

Fort Rinella

Fort Rinella is a Victorian fortification on the island of Malta. It is also referred to as the Rinella Battery in some maps and publications.-History:...

.

External links

• Page at Italian Navy official website

See also