WW1 Italian Submarines

An introduction: Italian Submarines in WW1

Italy during WWI operated no less than 21 different types of submersibles, from midgets to 1200 tonnes cruisers. In addition to most being built in the peninsula, some were also purchased abroad, like the H class built in Canada. This lineage started with the 1892 Delfino, a pioneering experiment, and went on until 1919 for some models. On the technological plan, Italy made famous its Laurenti Double-hull construction scheme, which was copied abroad, to the point the Royal Navy did purchase Laurenti boats for evaluation.

During the great war, no less than 68 submarines were operationally used, including the British/Canadian W, S and H types, as compared to the 22 that were operational in August 1914. Although it was less than the British or the US which had far superior industrial capabilities, or Germany, which bet its strategy on U-Boats past 1916, this force dwarfed the Austro-Hungarian navy and own submarine force, only 27 units strong. But this small force scared admiral Paolo Taon Di Revel enough to not risk his precious capital ships into the Adriatic, answering by mines, floatplanes, gunboats, MAS-boats and… submarines; They were thought of great value there, and spent indeed a large part of their operational service in this reduced theatre of operations of quiet and crystalline waters. This was a not so quite area of operations though, as the Regia Marina lost seven of them in operations. But their presence nevertheless confined the Austro Hungarian navy to a severely fortified and well-guarded Pola, which was thought impenetrable to submarines, but not to “special crafts” such as the Grillo. But that’s another story.

Glauco class at Brindisi, 1918

A technical definition of Italian Submarines

Italy started early on with submarines, much earlier than the Austro-Hungarians, but not as early as pioneers such as the Spaniards, French and Germans which in the late-middle of the XIXth Century already experimented with primitive models. It all started with the Delfino, the result of naval engineer Giacinto Pullino’s inspired researches. She had a petrol engine for the surface and electric motor for diving, and was completely rebuilt in 1904, and took her part in the great war.

Ansaldo Sestri Ponente NyD

Naval Yards:
RN Delfino was built at La Spezia, which became the main naval yard for submarines. There, submarines were built at the main Royal naval yard and arsenal, or at the Fiat-San Giorgio facilities at Muggiano, Venice Naval Yard (a few ones), Ansado, Sestri Ponente (in Genoa) and Orlando Leghorn, Odero, Sestri and Vickers Terni (also at La Spezia). Odero, Fiat-St Giorgio and Orlando merged in 1927, giving the birth of OTO (Odero-Terni-Orlando), still a major European player in naval systems. A few submarines were also built at Tosi, in Taranto.
Contrary to the Royal Navy, the Japanese Navy, or Austro-Hungarians, Italy did not feel the need to purchase its first models abroad. The country had the engineers and know-how for a home-grown submarine technology. The only exceptions were a single model, RN Atropo, built in 1912 at Germaniawerft in Kiel when Italy was allied with the central Empires. She was ordered in 1911 with Italian specificities to test ideas as well as evaluating German technology at the time. The other exceptions were transfers from the entente power this time, of ‘W’, ‘S’ and ‘H’ types to bolster the submarine force during the war.

Fiat San Giorgio Yard in Muggiano, adverstising postcard showing Laurenti’s Hvalen. Src cultureimpresa.it odf about the muggiano yard

Powerplants
The Italians were less inclined to research underwater performances, choosing the more conventional approach of the French and Germans related to submarine design, meaning designing a submersible torpedo boat. Performances when submerged were inferior to that in surface, in a ratio generally of 12/8 knots, while electric power was at least 50% inferior to diesel power for surface operations. In general, FIAT was trusted with the diesel engines, while Ansaldo provided electric motors (or rarely, Savigliano). They were exceptions of course, diesels were also swapped for petrol engines, generally FIAT, but Thornycroft models were used on some boats, Atropo having Krupp diesels and AEG electric motors, or Velella or the Medusa class, MAN diesels, the Nautilus class Sulzer diesels. Tosi yard also rarely delivered diesels, in the case of the “N” class. The “B” class midgets of 1916 had an Itala petrol engine (standard from a car manufacturer) which basically was an auxiliary power as most of the power came from electric motors on the three midget classes (see later).

Plan of the Medusa in 1911, showing the location of the Diesels. Src

Cesare Laurenti, “father of Italian submarines”

Special mention should be given to the designs of engineer Lt. Cdr. Cesare Laurenti.
Major of the Naval Engineers, graduated in naval and mechanical engineering at the Royal Naval School of Genoa on 7 June 1892, Cesare Laurenti was assigned in 1903 to the Royal Arsenal of Venice. In 1892 he became the director of technical experiments for the first Italian submarine, Delfino, driven by a battery-powered electric motor, designed by Giacinto Pullino. His contribution to the design in 1902-1904 was to add a gasoline engine, allowing a large surface cruising range, recharging batteries while underway. A scheme which was novel at the time.

His first serial project was the Glauco class of 1903. His goal was to built the first Italian serie of operational submarines, although still semi-experimental in nature. They were not very successful, but this first step made Laurenti, which designed new submarines until well into the interwar a bit of the “Italian father of submarines”. With time, his models emphasises hull’s strength to dive deeper, which brought him to develop his trademark double hull design, now a staple of submarine construction for a century.
Laurenti was frequently sent abroad to study hulls and engines for submarines and became a “dottore” on the subject, having great influence over the design of Italian submarines during this era.

The submarine Ballila in 1915 Src

He had indeed dedicated himself with great passion to the studies of submarines since the 1890s. His lobbying for the construction of these models in the Regia Marina and frequent publications in naval reviews stimulated the officers of the Regia Marina into believing this new type of warfare and its promises. In 1905 he became the Technical Director at the Muggiano shipyard of La Spezia, designing the revolutionary Foca, the following Medusa class, the Argonauta and mass-built wartime F-class, well suited for the Adriatic. He also built some in UK, the latter taking the opportunity to test his designs (S class). Laurenti would also direct the construction of submarines sold to other navies, like the Japanese. Their main features were always a strong double hull, internal compartments and plenty of power. He for example designed in 1909-10 the USS G-4 for the US Navy.

Other engineers of the time were G. Pullino (Delfino’s engines), Virginio Cavallini (the largest Italian submarines), Edgardo Ferrati (Italian midgets) and Curio Bernardis, probably the most famous Italian submarine designer after Laurenti. He created notably the first Italian minelayer submarines, the X2 class, and went on designing a large part of Italian interwar models.

Blueprint of Balilla

Armament of Italian submarines

Deck guns became a thing only from the Pullino class in 1913, the most common during the war being a 76 mm/30 AA, placed aft on the deck. Exception to this were larger submarines, which had two of them, or mixed caliber. For torpedo tubes, these were invariably the 450 mm model (17.7 in), since the refit of the Delfino in 1902. When Italy started to built submersibles again in 1925, they swapped to the international caliber of 533 mm (21 inches), and bow and stern tubes.

Submarine Zoea

Guns:
-3-inches/40 (76 mm)
-3-inches/30 AA (76 mm)
-57 mm (12 pdr)
-37 mm (6 pdr) both: Vickers Terni
Torpedoes:
-450 mm (17.7 in), standard for all Italian submarines
-356 mm (14 in) models (Delfino)

Read More/Src

Gardiner, Robert, Conway’s all the world’s fighting ship 1906-1921
http://www.hisutton.com/Mignatta.html
http://www.navweaps.com/Weapons/WTIT_List.php
https://www.treccani.it/enciclopedia/cesare-laurenti
http://www.navypedia.org/ships/italy/it_ss.htm
http://www.xmasgrupsom.com/Sommergibili/delfino1.html
https://en.wikipedia.org/wiki/List_of_submarines_of_Italy
http://www.betasom.it/forum/index.php?/topic/23615-classe-pacinotti-1914/
http://www.betasom.it/forum/index.php?/topic/35606-italian-q-ship-decoy-vessels/
http://www.grupsom.com/Sommergibili/F16..F18.html

Il Sommergibile “Giacinto Pullino” in navigazione (1916)

http://www.sommergibili.com/pullino.htm
http://www.agenziabozzo.it/navi_da_guerra/C-Navi%20da%20Guerra/C-2640_R_Smg_Giacinto_Pullino_1913_sommergibile_in_prove_di_navigazione_nel_Golfo_della_Spezia.htm

Prewar Italian Submersibles

Delfino (1892)

The very first submersible of the Italian Navy. Dates are foggy about the laying down and launch. 1892 is the generally accepted date, or 1892-95, down to 1889-1890. Completion is certain, 1892. It was designed at first by Engineer Inspector Giacinto Pullino, the design was at first known as the “Delfino-Pullino”. Her sea trials took place in La Spezia Naval Yard (if records are right) on 29 April 1892, with a commission on the 1st of April (1896).

Whatever the case, she was given three propellers, one in the horizontal axis and two in the vertical. What is important is its design was completely modified by Cesare Laurenti in 1902. She was made shorter while a petrol engine was added for accelerate diving and surface navigation. Her kiosk was also enlarged, and she was rearmed, from two 14-in to the standard 17.7 in tube. Despite her experimental nature, she did served in WWI.

Delfino, after her refit in 1904.

Specifications:
-Displacement: 95/107 tons – Post-refit: 102/113 tons
-Dimensions: 24.6 x 2.8 x 2.7 m. – Post refit: 24 x 2.8 x 2.5 m.
-Machinery: One Electric motor. Post-refit: +1 shaft petrol motor. 130/65 bhp, 6/5 knots.
-Armament: 2x 14 in (356mm) TTs. Post-refit: 1x 17.7 in (450 mm) TT.
-Crew: 1 officer, 7 sailors. Post-refit: 2+8.

Glauco class (1905)

Glauco, Narvallo, Otria, Squalo, Tricheco
Small submarines designed by Cesare Laurenti, semi-experimental as some modifications were introduced along their construction. Notably their torpedo tubes: RN Glauco had three, the rest two. They were all built in Venice Navy Yard, launched between 1905 and 1909. They were given two shafts FIAT or Thornycroft for Otaria and Trichero. But in any case, these engines were not reliable and a source of danger. Emanations of petrol easy to ignite. For diving they had two Savigliano eletric motors combining 170 hp. They served for harbour defence at Brindisi and Venice and were discarded in 1916 (Glauco), and 1918 for the others.

Specifications:
-Displacement: 95/107 tons – Post-refit: 102/113 tons
-Dimensions: 24.6 x 2.8 x 2.7 m. – Post refit: 24 x 2.8 x 2.5 m.
-Machinery: One Electric motor. Post-refit: +1 shaft petrol motor. 130/65 bhp, 6/5 knots.
-Armament: 2x 14 in (356mm) TTs. Post-refit: 1x 17.7 in (450 mm) TT.
-Crew: 1 officer, 7 sailors. Post-refit: 2+8.

Foca (1908)

This unique submarine was designed by the FIAT-San Giorgio Yards, a development of the Glauco, and first submarine with three shafts and propellers and three sets of FIAT petrol engines for a total of 800 bhp, allowing a top speed of 16 knots, making her the fastest Italian submarine in service. She was launched on 8 September 1908. On 26 April 1909, she suffered an engine explosion which set fire on her fuel tank while testing its powerplant in Naples. The fire became so fierce she was deliberately sunk in the hope to recover her later. She was indeed refloated and towed to la Spezia she was repaired and the powerplant completely changed. The central shaft was eliminated and the new engines developed 600 hp for 160hp underwater, 12/6kts in surface/dive in 1910. This painful experience definitely ruled out pretol engines in the Regia Marina. Foca was in limited harbour service in WW1 and was discarded in 1918.

Specifications:
-Displacement: 185/280 tons – Post-refit: ?
-Dimensions: 42.5 x 4.2 x 2.6 m.
-Machinery: 3 shafts petrol 800 hp, 2 Siemens Electric motors 600/160 bhp, 16/6 knots.
-Armament: 2x 17.7 in (457mm) TTs.
-Crew: 2 officers, 15 sailors

Medusa class (1911)

Argo, Fisalia, Jalea, Jantina, Medusa, Salpa, Velella, Zoea.

Designed by Eng. Lt. Cdr. Cesare Laurenti at FIAT-San Giorgio yards, they were the first Italian diesel submarines. They required long trials for design adjustments and were built in various yards: Argo, Jalea, Medusa, and vevella in Fiat-San Giorgio, Fisalia and Zoea in Orlando, Leghorn and Salpa, jantina in Riuniti Yards in Muggiano. They were launched between May 1911 (Velella) and August 1913 (Jalea) and therefore had only a few month of training before WWI broke out. The first, Velella, had a provisional machinery: MAN diesels and Siemens electric motors. Until 1915 they had some more time for adjustments and constituted a true success, widely used during the war. They were very good seaboats including underwater, agility and stability. Jalea was sunk by a mine in the gulf of Trieste on 17.8.1915, while Medusa was sunk off Porto di Piave Vecchia in northern Adriatic by the German UB15, maskeraded as the Austrian submarine U11. Zoea was beached on 26 November 1917 by storm at Rimini, she was salvaged by the Tug Ciclope to be repaired and assisted by Italian TBs. She was towed to Venice in 1st Dec. to be repaired, and resuled service until 1918. Argo at the same time was converted as an assault submarine to fice Pola by using forgmen to cut out the nets and barrages at the entrance. All remainder subs were stricken in 1918.

Specifications:
-Displacement: 248-252 surf. 305 tons sub.
-Dimensions: 45.1 x 4.2 x 3 m.
-Machinery: 2 shafts FIAT diesels, 2 Savigliano electric motors. 650/300 bhp 12/8 kts
-Armament: 2x 17.7 in (450 mm) TT, 4 torpedoes
-Crew: 2-3 officers, 19 sailors.

Atropo (1912)

This single submarine was ordered in Germany, then an ally. German data was 237/318t, contractual speed was 12/7.3 kts and her pressure hull was very strongly built, making her the deepest-diving Italian submarine at that point. She also had a very good surface speed and a range to match. The Italians refined in particular her outer casing shape and lines very similar to a torpedo boat, as requested by the RN. Atropo was launched at Germaniawerft on 22.3.1912 and served actively during WW1, stricken in 1919.

Specifications:
-Displacement: 231 surf. 320 tons sub.
-Dimensions: 44.5 x 4.4 x 2.7 m
-Machinery: 2 Krupp diesels, 2 AEG Electric motors, 700/200 bhp, 14.75/8 kts, Range 1300 nm/12.5 kts or 40 underwater at 8 kts
-Armament: 2x 17.7 in (450 mm) TT, 4 torpedoes.
-Crew: 2 officer, 12 sailors.

Nautilus class (1913)

Nautilus, Nereide.

These were the first models designed by Engineer Lieutnant Commander Curio Bernardis, a well-known submarine designer in the interwar. He created torpedo-boats capable of diving under water basically, and originally they were to have three torpedo tubes, with one installed on the deck, but it was never mounted. Both were launched at Venice Naval yard in April and July 1913 and were in service when WWI broke out. Nereide service life was rather short: She was sunk on 7 August 1915 near Pelagosa island by the Austrian submarine U-5. Nautilus was discarded in 1919.

Specifications:
-Displacement: 225 surf. 320 tons sub.
-Dimensions: 40.9 x 4.3 x 2.7 m
-Machinery: 2 shafts Sulzer Diesels, 2 Ansaldo electric motor 13.2/8 kts
-Armament: 2x 17.7 in (450 mm) TT, 4 torpedoes.
-Crew: 2 officers, 17 sailors.

Pullino class (1913)

Giacinto Pullino, Galileo Ferraris.
These two boats built at La Spezia and launched in July and November 1913 were deigned by Eng. Lt. Cdr Virgilio Cavallini for deep-diving. They were able indeed to reach 50 m underwater and was strongly armed with six torpedo tubes and several guns. In fact they were the first Italian subs with deck guns. They were also the largest submarines, although still classed as “small submarines” (piccolo sottomarino). Giacinto Pullino was sunk on 1.8.1917. She ran aground during the night of 30 to 31 July 1916 at Gadiola island off Suarnaro, sabotaged by her crew as she was to be captured by the Austrians, she sank when in tow to Pola, and was raised on 28 February 1931 by the Italian Navy to be scrapped. Ferraris was beached during the night of 27-28 November 1917 at Magnavacca during a storm. She was salvaged in January 1918 but in such a poor state she was never repaired and stricken in 1919.

Specifications:
-Displacement: 345 surf. 405 tons sub.
-Dimensions: 42.2 x 4.1 x 3.7 m
-Machinery: 2 shafts FIAT diesel 2 Savigliano electric motors.
-Armament: 6 x 17.7 in (450 mm) TT, 2 bow, 2 stern, 2 external, 57 mm, 37 mm deck guns
-Crew: 2 officers, 19 sailors.

Argonauta (1914)

A single, small submarine designed by Cesare Laurenti at the FIAT-San Giorgio Yards, la Spezia. She was basically an improved Medusa, with additions requested by the Russian Navy which ordered her in 1912 as Svyatoy Georgi. Among others, she had a second periscope, better motors, retractable horizontal rudders, and a signalling gear. However after WWI broke out, a young Lieutenant took possession of the boat, just launched since July. By then she was called N°43 in the yard. The officer with a small group of volunteer intention was to sail her in the Adriatic and sinking Austrian shipping, whereas Italy was still neutral, hoping to force the country to war. As the boat was near Corsica she was stopped by French Authorities and escorted back to Italy. When the country entered the war she was purchased from the Russian government and renamed Argonauta. She served until 1928, quite a long service for a submarine of this generation.

Specifications:
-Displacement: 255 surf. 306 tons sub.
-Dimensions: 45.1 x 4.2 x 3 m
-Machinery: 2 shafts FIAT diesels, 2 Savigliano Electric motors 700/450 hp, 13.5/8.8 kts, range 950 nm/12 kts
-Armament: 2x 17.7 in (450 mm) TT, 4 torpedoes.
-Crew: 2 officers, 22 sailors.