Top: CAGNI at her launching on 20 July 1940
Middle: Late 1942/early 1943 - CAGNI on her Atlantic Patrols
Bottom: CAGNI in her final Atlantic war patrol

The ocean going submarine AMMIRAGLIO CAGNI was one of the SAINT BON Class of submarines, planned at the end of 1939. The four submarines of this Class were the best to come out of the Italian submarine shipyards. These boats were AMMIRAGLIO SAINT BON, AMMIRAGLIO CAGNI, AMMIRAGLIO MILLO and AMMIRAGLIO CARACCIOLO and they had been planned according to the criteria of the oceanic war. As we see by the technical specifications here, they were large boats.

SPECIFICATIONS

Class: SAINT BON
Built by:Cantieri Riuniti dell’Adriatico, Monfalcone
Built over: 1938-1941
Dedicated to: Admiral Umberto Cagni (1863-1932), explorer of the Arctic group 1899-1900 and Commander in the Italio-Turkish War and in the First World War.
Displacement: 1,708/2,190 tons
Length: 87.9 meters
Beam: 7.76 meters
Draft: 5.72 meters
Power (diesel) 4,370 hp
Power (electric) 1,800 hp
Speed (diesel) 16.5 knots
Speed (electric) 8.5 knots
Bunkers: 180 tons
Range: (diesel) 20,000 miles at 5 knots
Range: (electric) 100 miles at 3.5 knots
Torpedoes: 14 to 36 torpedoes
Guns two 100mm .47 cal. deck guns
AA Guns: four 13.2mm automatic guns
Crew: 78 men
Operational depth: 100 meters

Immediately after their launch, the SAINT BON submarines were modified. The towers and external structure of the periscopes were reorganized and the rapid diving system was improved. The bridge of CAGNI was cut away, decreasing visibility of the boat. The submarines of the SAINT BON Class were created for war in distant seas, without the necessity of resupply from isolated tankers. They could travel 20,000 miles, carry 36 torpedoes & a tremendous story of provisions. However, rather than dispatch

AMMIRAGLIO CAGNI was attached to the VII Submarine Group for four missions in the Mediterranean which were primarily supply & transport missions. On 2 October 1942 CAGNI departed her base at La Maddalena and headed for the 12th U-bootflottille at Bordeaux, twelve miles up the Gironde River on the French coast.

CAGNI arrived in the Atlantic battlefield in those most difficult times. With the loss of ARCHIMEDE, the Italian fleet based at Bordeaux was at its lowest. The Italian submarines that went back into the Atlantic had been modified in the shipyards into nothing more than ‘mules’ to run supplies. Only CAGNI was supplied with naphtha and torpedoes, and was sent into the Indian Ocean along the merchant routes, somewhat isolated from the mainstream of ships. With the loss of da VINCI, CAGNI was the only Italian boat still operational in the Atlantic.

One of the unusual bits of information about CAGNI is that she did not mount the normal 553mm (21 inch) torpedoes used by almost all submarines of all nations but had smaller 450mm torpedoes. These were not very effective to sink warships, but they could easily take down merchant ships and tankers. These torpedoes were much smaller and lighter and so, they could stow 36 of them aboard CAGNI. With her eight bow tubes and 6 stern tubes, she posed a formidable threat to any ship that she found.

After she transited the Straits of Gibraltar outbound, she cruised down the African coast and took position off Freetown. She did not have an uneventful patrol. For instance:

3 November 1942, she torpedoed and sank the 3,856 ton English steamer RMS DAGOOMBA;

29 November 1942, sank the 1,995 ton Greek steamer SS ARGO;

3 January 1943, CAGNI attempted to hand over some torpedoes to the submarine TAZZOLI, but the rough seas stopped the action.

11 January 1943, CAGNI receives naphtha (fuel) from the German U-tanker U-459 and then receives orders from Bordeaux to patrol off the coast of Brazil. U-459 has only six more months to live but of course, no one knows it at this time.

CAGNI finds no targets off Brazil and returns to her berth at the French base Bordeaux on 20 February 1943.

In the spring of 1943, CAGNI was modified in the Bordeaux ship yards. The tower was again cut down to reduce visibility. She is painted with camouflage seen above and by June, is ready for sea. 29 June 1943, CAGNI departs Bordeaux for the long ride to the Far East where she is to patrol Freetown, Capetown and finally arrive at the Japanese submarine base in Singapore. This was the very last war patrol of any Italian submarine.

12 July 1943, CAGNI attacks an unidentified ship off Madagascar but there is no success;

25 July 1943, CAGNI encounters an English convoy off Freetown and attacks. She hits and damages the 22,048 ton auxiliary cruiser HMS ASTURIAS which returned to Freetown for repairs. The Skipper of CAGNI erroneously reported this ship as an aircraft carrier escorted by three destroyers.

CAGNI remains in the Capetown area for a month, but contacts no enemy shipping or targets of any kind. At the end of August, the Skipper decides to head for Singapore. However, they are never to arrive in the Far East as on 8 September 1943, the CAGNI receives word of the Italian capitulation.

The Italian superiors in Rome order the Skipper to surrender to the British and to hand over CAGNI to the enemy.

The German superiors order CAGNI to continue hostilities as a German submarine. What to do?

After twelve days of uncertainty, the crew decides to obey the Italian King and on 20 September 1943, CAGNI is delivered to the British base at Durban, South Africa.

After the war, she was used to train Allied submarine crews in the Mediterranean and in 1948, she was decommissioned and broken up. She was the only one of the four SAINT BON submarines to survive the war - indeed, to even survive the first few months of their time in the conflict.

VINCENT - as always, this is outstanding. Many thanks!

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