Radiomir Depth Gauge Officine Panerai "Italian Royal Submarine Ciro Menotti", circa 1939
Depth Indicator Pressure Gauge in "Sea Water Column Meters" (Depth Gauge) equipped with the innovative "RADIOMIR Self-illumination" system, created by the "Officine Panerai Firenze", was installed on the Submarines of the Royal Italian Navy.
In 1916, to satisfy the military needs of the Royal Navy with which it had already been collaborating for some years, Panerai created Radiomir, a substance that allows the dials of instruments and aiming devices to be made luminous. The reference to the name “RADIOMIR” is documented in the patent filed in France on 23 March 1916. The exceptional visibility that this substance offered and the excellent resistance of the paint even immersed in water immediately made it a main element of the production Panerai workshops. The RADIOMIR was the first of numerous registered patents that distinguish Panerai's history of innovation.
In 1936, the 1st Grupsom of the Royal Italian Navy requested a wristwatch from the Officine Panerai Florence to make it available to its "Gamma" raiders which was capable of tackling sea dives and which offered excellent visibility in deep waters. and not clear: this was how Panerai developed the self-illumination technology called "RADIOMIR", making the first supply of watches in 1938.
The Royal Italian Navy, starting from 1939, decided to apply this new technology also on some main "Depth Indicators or Depth Gauges" instruments, installed in the maneuvering/command room of its Submarines, so that the numerical scale relevant to the depth could be "read" even in a situation of total absence of light.
This pressure gauge, "Depth Indicator or Depth Gauge" shows a graduated scale that measures from "0" to "120" meters of sea water column, divided meter by meter.
It is also equipped, applied on its dial, with a "Clinometer" (with a scale from 0° to 20°), which had the purpose of indicating the degree of inclination with which the Submarine submerged or emerged and was also backlit by the "Self-illuminating RADIOMIR" system.
This "Depth Gauge" has, applied on the metal support plate (on the back), a paper label (wax paper) which certifies the placement of the instrument, in the year 1940, on the C. Menotti Submarine, with relative alphanumeric references .
An extremely relevant detail is given by the fact that, upon Italy's entry into the war in 1940, there was the Navy Ace: Lieutenant Carlo Fecia di Cossato.
Only known surviving example.
The Italian Royal Submarine Ciro Menotti clandestinely participated in the Spanish war. On 31 January 1937, at night, she torpedoed and sank the 1250 GRT steamship Delfin (the ship sank in shallow waters making it possible to recover the cargo).
On 2 and 3 February 1937 she bombarded the coastal roads and bridges in the Herradura-Cala Honda area with cannon.
When Italy entered the Second World War you were stationed in Trapani, under the command of Lieutenant Carlo Fecia di Cossato, within the VIII Grupsom.
On 21 June 1940 she set off on her first mission, an offensive patrol in an area between the islet of Gaudo (Crete) and Ras el Tin (Libya).
In November of the same year it was sent together with four other submarines to the Ionian Sea; despite considerable British naval activity in the area she did not sight any enemy units.
Between June 1940 and January 1942 she carried out a total of 23 offensive-exploratory missions in the eastern Mediterranean.
From May 1942 he was assigned to transport supplies to Libya, carrying out eight such missions.
In all, from June 1940 to March 1942, she traveled 22,200 miles on the surface and 2,800 miles submerged, in 29 missions.
On 7 March 1943 he was assigned to the Submarine School in Pola for which he carried out 53 training missions.
On 3 August 1943, at night, 19 saboteurs from the San Marco Battalion landed near Benghazi, commanded by Lieutenant Di Martino: their task was to attack the Anglo-American airfields in the Benghazi area.
At the beginning of September 1943, as part of the "Zeta Plan" to counteract a planned Anglo-American landing in southern Italy, it was placed in ambush in the Ionian Sea.
After the announcement of the armistice he headed for Syracuse to hand himself over to the Allies, but was intercepted by the British submarine HMS Unshaken, which boarded him with its own launch carrying a crew of plunder, diverting him to Malta where he arrived on 12 September, mooring at Lazaretto Creek (near the local British submarine base); the following day, following the protests of Admiral Da Zara, it returned to Italian hands and moored together with the other Italian units that had arrived in the meantime. On 13 October he left the island – together with 14 other submarines – to return to Italy.
During the co-belligerence he operated in the eastern Mediterranean basin taking part in various Allied anti-submarine exercises.
She was disarmed in 1945 and deregistered on 1 February 1948, subsequently sent for demolition.
Officine Panerai was founded in 1860 in Florence by Giovanni Panerai (1825-1897) who opened a small high-precision mechanical and watchmaking business on the Ponte delle Grazie. In the following years, with the passing of Giovanni Panerai, his nephew Guido (1873-1934), son of Leon Francesco, Giovanni's eldest son, took over the reins of the company. After several moves it moved to the "historic" headquarters par excellence in S. Giovanni Square in front of the Baptistery, in the Archbishop's Palace.
Swiss watchmaking becomes the dealer of the most important Swiss watch brands, first of all Rolex with which an exclusive and privileged relationship was created which helped to build the first Panerai watches. Guido Panerai was a man rich in inventiveness, he attended the academy of fine arts and was also a talented painter, he set up another business, the "Guido Panerai Officina Meccanica". He had 2 children: Maria and Giuseppe, with the latter in 1925 he opened Guido Panerai & Figlio with the business name of trading in precision tools and watchmaking supplies." Giuseppe was a brilliant person, a man passionate about his work, he invented and he patented the most disparate things, but the "breakthrough" invention was that of the Radiomir. It was a process for making instrument dials, sighting devices and telescope reticles self-luminous.
The process obtained by using a mixture of phosphorus and radioactive material in paste, was introduced into alveoli obtained in the material constituting the dial of the instrument or the reticle of the telescope, or into tubes of transparent material. Radiomir brought the attention of the Royal Navy to this company, which celebrated the self-luminous achievements of the MAS and the targeting systems for cannons. In the following years, the company's activities became totally conditioned by the needs of the Royal Navy.
In 1936, the first submarine group of the Royal Navy asked Officine Panerai for a wristwatch capable of facing sea diving and offering visibility in deep, unclear waters. The Radiomir watch was born. Obviously prototypes were prepared, with a dial with bar indexes and dots with various types of dial including a Rolex California dial-inspired dial, i.e. the upper half with Roman numerals and the lower half with Arabic numerals.
Then, with the dial with Arabic numerals at the cardinal points and bar indices, in one of the first prototypes with a composite bakelite dial, fixed to the brass back by 2 rivets in the center of the dial itself.
In 1938 the first supplies to the Royal Navy began. The dial was a sandwich or also known as the Paris model (name of its inventor), i.e. composed of two parts, the lower part was a "little box" which contained the radium mixture (contained by a veil of plexiglass) and the upper part with the perforated numbers and indexes. The case is 47mm cushion-shaped steel, with wire-welded lugs, screw-down crown engraved with the Rolex crown.
The custom forge screw-down caseback opens via a special faceted key supplied by Rolex. Inside the case back the Rolex hallmarks, serial and reference numbers.
The glass is a kind of plexi, called Perspex about 4 mm thick. These watches were on the wrists, during the Second World War, of the Sailors of the assault vehicles of the to his second Emilio Bianchi, one of the 3 pairs of stormtroopers of the 2 flagships of the English fleet in the Mediterranean. They were on the pulse of the MOVM Luigi Ferraro while alone in the spring of 1943 he sank 4 ships off the port of Alessandretta (Turkey). They were on the wrist of Licio Visentini, another Gold Medalist of the
They were also awarded to soldiers of other nations, the German Kampfschwimmers of the Kriegsmarine, who trained with the Gammas of the Xth MAS Flotilla during the RSI period in Italy. These watches had no wording on the dial, anonymous, but certainly made by Panerai.
All the straps mounted on the Panerai were in die-cut leather and long in size to be worn over the wetsuit, with an appropriately sized pin buckle. In addition to watches, Panerai supplies other wrist items such as compasses and depth gauges with various scales for different uses, these objects had a diameter of approximately 70 mm, and are now highly sought after by collectors.
During the conflict, the "G. Panerai & Figlio mechanical workshops" intensified their projects for the Royal Navy, some marketed or rather sold to the Navy itself and others remained in prototype status, this is the case of the Mare Nostrum chronograph. Watch made in a couple of examples intended for Navy Officers, it will only be marketed in the distant future.
Also during the conflict, the Radiomir project was especially evolved, the experience and prolonged use in hostile environments highlighted where to intervene to improve: first of all the wire lugs were abandoned as they tended to unsolder, bend and even tear.
Sometimes, however, prolonged use of the crown wore out its sealing gasket and did not guarantee the waterproofness necessary for the watch to flood. This inconvenience was resolved with a patent which today is the Panerai trademark, namely the bridge crown protector: a steel crescent with an eccentric lever that always tightens the crown to the same position. Simple but effective patent, its design makes the watch unmistakable (the watertightness of the watch is 20 atm equal to 200 m). This device was only patented in the second half of the 1950s, but its use had already been in place for over a decade.
After the war, the collaboration between Panerai and the newly formed Italian Navy continued. New supplies were requested to be entrusted to their special departments, as well as watches, compasses, depth gauges, torches and knives, including the Galeazzi knife built to the specifications of the newborn Comsubin.
However, a distinctive element of Panerai watches could no longer be used because it was considered harmful, Radiomir, so a tritium-based mixture called LUMINOR was studied and also replaced the wording on the dials themselves.