Bragadin class submarine (1929)

Coastal Submersibles (1931-48): Marcantonio Bragadin, Filippo Corridoni

The Bragadin-class were four submarines built for the Regia Marina in 1927-31 by Cantieri navali Tosi di Taranto, Taranto. The class comprised two boats, and they were essentially minelaying versions of the earlier Pisani class, sharing the latter’s stability issues and needed to be modified to correct those after completion. In all they could carry 16 or 24 mines depending of the types and still had four torpedo tubes and a deck gun. Their 4200 nm range brought them in range of the African coast and either the Aegean or Thyrrenian seas from Italy. Bragadin had a collision in 1935 with Tito Speri. She had a single minelaying mission and made 11 wartime transport ones and 65 of training due to her age. Her sister Corridoni had 23 patrols and 15 transport missions, both escaped capture at the armistice and had different roles until scrapped in 1948.

Design of the class

Corridoni Taranto

Development

In the interwar, the Italian submarine arm was constituted around missions of coastal, long range patrol and trade lines disruptions, as well as minelaying. The Regia Marina decided to build mine-laying submarines types with better performances than the now old three WWI legacy boats of the X class. The intention was to build a medium displacement submarine, good for operations outside the Mediterranean and keeping balance between torpedoes and mines to have the best of opportunities. This project was assigned to Admiral Engineer Curio BERNADIS, a famous Italian submarine designer which already drawn plans of really good submarines and curcially, the mine-laying submarines X2 and X3 class derived from the X1 class. The latter was rebuilt from the captured Austrian U24 (previously UCF 12, a German model), sunk by one of her own mines in front of Taranto, on 16 March 1916 and later salvaged.

Hull and general design

The Bragadin belonged to the Bernardis type with a single hull with central double bottom. They essentially derived from the Vettor Pisani class but modified to integrate mine wells. The latter were stored in two horizontal tubes in aft hull. The Bragadin class displaced 981 metric tons (966 long tons) surfaced, 1,167 metric tons (1,149 long tons) submerged. In size they were 71.5 meters (234 ft 7 in) long, for a beam of 6.15 meters (20 ft 2 in) and draft of 4.8 meters (16 ft). However they developed various problems with poor stability, and an excessive pitching seeing them tipping towards the bow in rough seas. These problems prompted a reconstruction in 1935 with the installation of bulwarks and bulges, stern shortened and raised. The bow had extra buoyancy and a modified shape, resulting however in more drag and a reduction in speed.

After this refit they measured 68 meters (223 ft) in length with a larger beam at 7.1 meters (23 ft 4 in) and draft of 4.3 meters (14 ft 1 in). Their operational diving depth was 90 meters (300 ft) and crew comprised 56 officers and enlisted men. They had also an inefficient mine-laying system which was in fact used only once in war. Therefore this design was never repeated and in wartime they were mostly used for transport and training.

Powerplant

On surface they were powered by two 750-brake-horsepower (559 kW) diesels, driving each a propeller shaft. When submerged, electric engines took relay, rated for 500-brake-horsepower (373 kW). They could reach 11.5 knots (21.3 km/h; 13.2 mph) surfaced, 7 knots (13 km/h; 8.1 mph) underwater. While surfaces their range extended to 4,180 nautical miles (7,740 km; 4,810 mi) at 6.5 knots (12.0 km/h; 7.5 mph). This was enough to reach the canary islands or the black sea, or the tip of the red sea. Submerged, they had a range of 86 nmi (159 km; 99 mi) at 2.2 knots (4.1 km/h; 2.5 mph), ideal for approaches on contested waters to lay mines.

Armament

The Bragadin had four internal 53.3 cm (21 in) bow torpedo tubes and only six torpedoes, four pre-loaded, two in reserve. In the stern they had two horizontal tubes accommodating either 16 or 24 naval mines depending on the type. When surface they could count also on their OTO 102 mm (4 in) deck gun and an anti-aircraft armament comprising two 13.2 mm dingle pintle-mounted (0.52 in) Breda heavy machine guns.

OTO 100mm/47 modello 1931

Derived from the Škoda 10 cm K1, but with loose liners. A tube, jacket and loose liner with a breech ring that screwed to both the A tube and jacket. Barrel shortened to 4.94 m (16 ft 2 in). Single, hand-worked and unshielded, pedestal-mounts fore and aft of the CT. The Bragadin had a lowered platform, to the deck level, instead of the breakwater style of the Bandiera, and carried 150 shells in store, either 22 kg AP or smaller 13.8 kg conventional HE shells.

Specs:
Shell: 100 millimetres (3.9 in), fixed 13.75 kilograms (30.3 lb) QF 100 x 892R
Breech: Horizontal sliding breech block
Elevation/Traverse: -5° to +45° for 360°
Rate of fire: 8-10 rpm
Muzzle velocity: 880 meters per second (2,900 ft/s)
Max range: 15.2 km (9.4 mi)

AA: 2x Breda Modello 31

The anti-aircraft defence counted on two twin Breda M1931 13.2 mm L/76 heavy machine guns, placed on a rear platform of the conning tower. Each mount weighed 695 kg, but ensured an elevation of -10° to 90°. They fired 125 g unitary rounds, but through clips containing 30 rounds each. Muzzle velocity of 790 m/s, maximum range of 6,000 meters and effective range of 2,000 meters. Their rate of fire was 500 rounds/min, so 2000 rounds when both twin mounts fired in concert, however. These were retractable mounts, receding into a water-tight tube and protected by a small hatch. Upon emerging, gunners released the hatch, lift the guns out and install a clip to be ready.

533 mm torpedoes

Model unknown. When completed they probably had the dollowing models introduced in 1932-36:
-W 270/533.4 x 7.2 Veloce: 1,700 kg, 7.2 m WH 270 kg, 3,000-4,000 m/50 knots or 12,000 m/30 knots.
-W 270/533.4 x 7.2 “F”: 1,550 kg, 6,500 m, WH 250 kg, speed 3,000 m/43 knots or 10,000 m/28 knots
-W 250/533.4 x 6.5: 1,550 kg, 7,200 m, WH 270 kg, 4,000 m/48 knots or 12,000 m/30 knots.
-Si 270/533.4 x 7.2 “I”: 1,700 kg, 7.2 m, WH 270 kg, speed 3 km/42 kts. or 7 km/32 kts., 9,2km/30 knots, 12km/26 kts
-W 250/533.4 x 6.72: 7.2m, WH 270 kg speed 4km/49 kts. or 8km/38 kts.
-Si 270/533.4 x 7.2 “M”: 1,7 ton, 7.2 m, WH 270 kg speed 4km/46 kts., 8km/35 kts or 12km/29 kts.

Mines

P150 and P150/1935 Mines

These were manufactured by Pignone, specifically designed to be laid by submarines such as the Foca, Micca and Bragadin classes. Their warhead was either 265 or 331 lbs. (120 or 150 kg) and they had mooring cables 990 feet (300 m) long.

Dedicated illustration planned

⚙ Bragadin specifications post-refit
Displacement	846 t (833 long tons) surfaced, 997 t (981 long tons) submerged.
Dimensions	68 x 7.1 x 4.3m (223 ft 1 in x 23 ft x 14 ft 1 in)
Propulsion	2 shafts; diesel-electric 1,500 bhp (1,100 kW)/1,100 hp (820 kW)
Speed	11.5 knots (21.3 km/h; 13.2 mph) surfaced, 7 knots (13 km/h; 8.1 mph) submerged
Range	4,180 nmi/4.5 knots surfaced, 86 nmi/2.2 knots submerged
Armament	102 mm deck gun, 2×1 13.2 mm HMG, 4× bow 533 mm TTs, 2 stern mine tubes (16/24)
Max test depth	90 m (300 ft)
Crew	56

Career of the Bragadin class

Marcantonio Bragadin (1929)

Marcantonio Bragadin, named after a famous 16th cent. Condotierre, notably for the battle of Famagosta, was laid down at Cantiere Navale Triestino, Trieste on 3 Feb 1927, launched on 21 July 1929 and commissioned on 16 Nov 1931. She was originally named “Bragadino” and after completion, was stationed in La Spezia with the II Submarine Squadron. In 1934, she was transferred to Taranto. On December 7, 1935, she was accidentally rammed by the submarine Tito Speri, listing violently from the impact but without suffering serious damage or casualties. She was refitted and partly rebuilt to cure her stability issues like her sister in 1935-36. In 1939, she was seconded to the Command School Flotilla, remaining there for several months.

Aside from training when the Second World War broke out for Italy in June 1940 she was stationed in Taranto and from there, used almost exclusively on transport missions. On 24 June 1940 under the command of Lieutenant Commander Bandino Bandini, she departed Naples for her first mission, transporting 27 tons of supplies for the Italian Air Force at Tobruk. Recent research suggests that she had a stopover in Tobruk on 28 June, and not the armored cruiser San Giorgio, firing and accidentally downing Italo Balbo’s plane. Bragadin returned to Taranto on 4 July after intense and continuous allied ASW hunting, a total of three air attacks and two depht charge attacks causing the loss of four men, two petty officers and two sailors as well as substantial damage.

She underwent repairs that lasted several months at the Taranto Arsenal. On October 30 under Lieutenant Commander Mario Vannutelli she performed had single minelaying mission of the war, laying 24 mines near Navarino. I was there that her minelaying system was actually used and found inefficient. Between December 9, 1940, and October 1, 1941, she stayed with the Pola Submarine School, performing 65 training sorties and three surveillance missions in the Upper Adriatic, out of reach of the allies. She was then redeployed to Messina and later to Taranto.

On December 17, 1941 under command of Lieutenant Luigi Andreotti she left Taranto for Benghazi with 50 tons of supplies, heading for Tripoli. However she later ran aground near Punta Tagiura, close to her diestination, having to transfer the cargo to motorboats. She was then refloated, and towed to Tripoli by the tug Ciclope. Repaired in drydock, she returned to Taranto in January 1942. On 21 May 1943, she was ambushed by a British submarine but dodged four torpedoes while back from a transport mission from Lampedusa to Taranto. In total she performed eleven transport missions. On 7 September 1943 the “Zeta Plan”, to counter the upcoming Allied landing at Salerno saw her deployed in the Ionian Sea.

With the armistice of Cassibile she was fortunately oput of reach of the Germans and laid in wait in the Gulf of Taranto until instructed to surrendered to the Allies at Augusta. From there, she departed with five other submarines under escort by HMS Isis to avoid being accidentally attacked by Allied aircraft, to Malta. She dropped anchor there on 16 September. In total, she ahd performed 28 missions, covering a total of 16,153 miles surfaced, 1,581 submerged. The allies decided to use her for training, and on 13 October, she returned to Italy with 15 other submarines. She was assigned to the Levant Submarine Group, and employed for anti-submarine training to British escort ships in Haifa, and then her age showed up, she was sent back under tow to Taranto after an engine breakdown. From 26 October 1943 in Haifa at she was supposed to transport supplies to the besieged Leros (by the Germans) but was deemed unfit and returned to Italy to be deactivated. Her logs for the remainde rof WW2 and postwar years are unknown. She was probably kept in reserve and decommissioned on 1 February 1948, then scrapped.

Filippo Corridoni (1930)

Filippo Corridoni was named after a fellow trade unitionist and friend of Mussolini, co-founder of the Fasci d’Azione Rivoluzionaria in 1915. She was also laid down at 4 Jul 1927 at CNT and launched on 30 March 1930, commissioned on 17 Nov 1931. During the Second World War, she was used transporting supplies, completing such 15 missions. Her first mission on 30 June 1940 started from Naples, transporting 27 tons of supplies to Tobruk, where she arrived on 3 July, after a trip of 20,960 miles surfaced and 2,172 submerged. Between 1940 and 1943 she also carried out 23 patrol missions and 7 transfer to various bases. At the armistice, she was surrendered to the Allies in Palermo. From there, she sailed on 20 September 1943, together with five other Italian submarines and other vessels to Malta where the allied commission was to decide of their fate. On 13 October, she returned to Italy, together with 15 other submarines and it was decided like her sister to use her for ASW training. However in October 1943, she was relocated to Haifa, and by October 29, landed at Portolago, resupplying the island of Leros before its fall to German occupation. No logs exist for her subsequent service in the co-belligerence and postwar years. She was struck off on February 1, 1948, and later scrapped.