Perla-class submarine

The Perla-class submarines were essentially repeats of the preceding {{sclass|Sirena|submarine|4}}. The modifications that were made compared to the boats of the previous series were mostly of upgrade nature. Among them were enlargement of the false tower at the top, more modern engines, installation of a radiogoniometer that could be controlled from inside the ship. Improvements and the installation of new air conditioning equipment meant a slight increase in displacement, and increase in the fuel stowage also increased the autonomy of these boats compared to the previous series. Their designed full load displacement was {{convert|695|t|LT|sp=us}} surfaced and {{convert|855|t|LT|sp=us}} submerged, but varied somewhat depending on the boat and the builder. The submarines were {{convert|197|ft|6|in|m|sp=us}} long, had a beam of {{convert|21|ft|m|sp=us}} and a draft of {{convert|15|ft|m|sp=us}} to {{convert|15|ft|5|in|m|sp=us}}.Bagnasco, p. 153

For surface running, the boats were powered by two diesel engines, each driving one propeller shaft with overall power of {{convert|675|-|750|hp|abbr=on|lk=in|0|adj=on}}. When submerged each propeller was driven by a {{convert|400|hp|0|adj=on}} electric motor. They could reach {{convert|14|kn|lk=in}} on the surface and {{convert|7.5|kn}} underwater. On the surface, the Perla class had a range of {{convert|5200|nmi|lk=in}} at {{convert|8|kn}}, submerged, they had a range of {{convert|74|nmi|abbr=on}} at {{convert|4|kn}}.Bagnasco, p. 153

The boats were armed with six internal {{convert|53.3|cm|in|1|abbr=on|sp=us}} torpedo tubes, four in the bow and two in the stern. One reload torpedo was carried for each tube, for a total of twelve. They were also armed with one Škoda 10 cm K10#OTO 100.2F47 History deck gun for combat on the surface. The light anti-aircraft armament consisted of one or two pairs of Breda Model 1931 Machine Gun machine guns.Chesneau, pp. 309–10

The boats, once commissioned, were assigned to complete the squadrons of "600" submarines from La Spezia (12th and 13th Squadrons) and Messina (34th and 35th Squadrons) and began their training and exercises in metropolitan waters, and underwent endurance training predominantly in the Dodecanese and, to a lesser extent, along the coast of North Africa. These endurance exercises took place in 1936 and 1937, soon after the initial training was finished.

{{ship|Italian submarine|Iride||2}} and {{ship|Italian submarine|Onice||2}} were "lent" to the Nationalist side during the Spanish Civil War, under the names of Gonzales Lopez and Aguilar Tablada respectively, in the framework of Italy's aid to Franco's regime. They retained their Italian crews but had a Spanish liaison officer on board. They were returned to the Italian Navy at the end of the conflict.

In 1938 {{ship|Italian submarine|Perla||2}} and {{ship|Italian submarine|Gemma||2}} were sent to the Red Sea base of Massawa and returned the following year replaced by {{ship|Italian submarine|Onice||2}}, {{ship|Italian submarine|Berillo||2}} and {{ship|Italian submarine|Iride||2}} who in turn returned to Italy before the outbreak of World War II. Between 1938 and 1940 {{ship|Italian submarine|Ambra||2}} and {{ship|Italian submarine|Malachite||2}} were for long periods of time deployed outside of Italy, mainly in Tobruk.

At the outbreak of hostilities, four boats were located at La Spezia, three in Cagliari, two in Augusta and one, {{ship|Italian submarine|Perla||2}}, in Massawa.

After a disastrous start to the World War II when Italy lost ten submarines in the first twenty days, and the Regia Marina and Regia Aeronautica did not fare much better, Italian command decided to speed up implementation of experimental SLC technology. In July 1940 {{ship|Italian submarine|Iride||2}} was modified to carry 4 "Maiale" manned torpedoes in watertight containers on the deck of the submarines. {{ship|Italian submarine|Iride||2}} was sunk while conducting tests, before she could be employed against British naval units. {{ship|Italian submarine|Ambra||2}} underwent conversion to SLC in March 1942 with three SLC units being fitted onto her deck. With a weight of 2.8 tons, these SLC cylinders were able to withstand depths up to 90 meters, about three times more than those installed on {{ship|Italian submarine|Iride||2}}. In December 1942,

{{ship|Italian submarine|Ambra||2}} managed to penetrate Algiers harbor, and sank or seriously damaged several merchant ships with a total GRT over 20,000.

In common with other Italian submarines the survivors were fitted with smaller conning towers in 1942–43.

Overall, the Perla class submarines proved to be quite successful. They showed good maneuverability, their hull was well designed and strongly built to withstand depth pressure and explosions that exceeded their test values.

• Italian submarines of World War II

{{reflist|30em}}

• {{cite book|last=Bagnasco |first=Erminio |title=Submarines of World War Two |year=1977 |publisher=Naval Institute Press |location=Annapolis, Maryland |isbn=0-87021-962-6}}
• {{cite book|title=Conway's All the World's Fighting Ships 1922–1946|editor1-last=Chesneau|editor1-first=Roger|publisher=Conway Maritime Press|location=Greenwich, UK|year=1980|isbn=0-85177-146-7}}
• {{cite book|editor-last=Gardiner |editor-first=Robert |editor-first2=Roger |editor-last2=Chesneau |title=Conway's All the World's Fighting Ships 1922–1947 |location=London |publisher=Conway Maritime Press |date=1980 |isbn=0-85177-146-7}}
• {{cite book|last=Rohwer|first=Jürgen|title=Chronology of the War at Sea 1939–1945: The Naval History of World War Two|publisher=Naval Institute Press|location=Annapolis, Maryland|year=2005|edition=Third Revised|isbn=1-59114-119-2|authorlink=Jürgen Rohwer}}

• [https://www.marina.difesa.it/noi-siamo-la-marina/mezzi/mezzi-storici/Pagine/sommergibili.aspx Sommergibili] Marina Militare website

{{Portal bar|Italy|Engineering}}

{{Perla-class submarine}}

{{Italian 600 Series submarines}}

{{WWII Italian ships}}

{{SpanishCivilWarShips}}

Category:Italian 600 Series submarines

Perla

Category:Military units and formations of the Spanish Civil War (National faction)