Squalo class submarine (1930)

Coastal Submersibles (1930-48): Delfino, Narvalo, Squalo, Tricheco

The Squalo-class were four submarines built for the Regia Marina in 1928-30 by the Cantieri Riuniti dell’Adriatico (CRDA) shipyard at Monfalcone, designed by Curio Bernardis. They were essentially a development of the previous Bandiera class, at 900 tonnes surfaced, and capable of 15 knots. They paid a heavy price to WW2 operations: Delfino sank after a collision off Taranto on 23 March 1943, but Narvalo was sunk by the destroyers Pakenham and Hursley and the RAF on 14 January 1943. Squalo survived but was withdrawn from service on 9 September 1943, whereas Tricheco was sunk by the HMS Upholder off Brindisi on 18 March 1942.

Design of the class

Development

The Squalo-class were essentially repeats of the preceding Bandiera class and since they were started before the first were on trials, they repeated that design’s problems of stability and seakeeping. Later they required a similar hull bulging to solve these, as well as modifying their bow shape for extra seaworthiness improvement. Designed by Curio Bernardis, they shared overall close design features also with the earlier Pisani class, making for a global “early Bernardis” superclass. In common, they were suitable for operating in warm seas, such as the Red Sea.
The next Argonauta class introduced many new improvements and are considered later, better designs of Bernardis. The previous Bandiera had indeed a tendency to dip down by the bow, solved by the use of a special autofilling tank would stay empty and give extra buoyancy when surfaced by fill up in immersion, in addition to the bulges. The Squalo also adopted this system, as well as the peculiar bow created for the Bandiera, “big nose”, or “nasone”. The Squalo were laid down too soon to be corrected and had to be so later at great cost after they were ordered to Cantieri Riuniti dell’Adriatico (CRDA) shipyard at Monfalcone.

Hull and general design

The Squalo were a bit larger than the Bandiera. They displaced 920 metric tons (910 long tons) surfaced and 1,125 metric tons (1,107 long tons) submerged. Length was increased, at 69.8 meters (229 ft) long overall for a beam of 7.21 meters (23 ft 8 in) and draft of 5.19 meters (17 ft). The pressure hull was built the same as before, with various cylindrical sections sealed at both ends by semispherical cups for six primary compartments. The torpedo tubes protruding from such a cone forward.
A second cylindrical was enclosed in the conning tower. The outer hull had to be seaworthy and within the outer shell were located ballast or oil tanks, external ballast or compensation tanks. There were double internal ballast tanks. Originally, the bow was straight and thin with some flare like a ship, but it dipped too much and had to be modified as more buoyant. Diving depth in operation was around 90 meters (300 ft), with a probable crush depth double that. The crew was the same as before, it amounted to 53 officers and enlisted men.

Powerplant

The Squalo class like the Bandiera were equipped with the new FIAT Q 426 six-cylinder, two-stroke reversible 1,500 HP (1,119 kW) diesel engines, which improved less surface speed and more improved the endurance compared to the Pisani. This gave them the same top speed of 15.1 knots (28.0 km/h; 17.4 mph) surfaced. Range was 5,650 nmi (10,460 km; 6,500 mi) at 8 knots (15 km/h; 9.2 mph).
The CRDA (Savigliano for Bandiera) electric motors installed could produce 650 HP each (485 kW). However, performances were degraded somehwat compared to the bandiera, 7 miles at 8 knots (15 km/h; 9.2 mph) versus 8.8 miles at 8.2 knots notably due to a larger and heavier hull. However at creeping speed, this improved, that is 100 nmi (190 km; 120 mi) at 3 knots (5.6 km/h; 3.5 mph). The Pisani and Bandiera, like the Squalo had two 56 cell storage batteries from likely SGIAE of Melzo near Milan and developed 4,270 amps for one, 6,380 for 3 hours, 8,400 for 10 hours and 9,350 for 20 hours. The total weight of these batteries, which acted as ballast, was c80 tonnes.

The Squalo, like previous classes, had the same primary air compressor was installed in the compartment forward of the control room from San Giorgio. It was able to pressure air to 200 kg.cm2 (2845 psi) and the compressors were electrically powered. In addition, there were also two San Giorgio super compressors to boost air pressure from 70 to 200 kg.cm2 (995 to 2845 psi), receiving air from the two compressors built into the diesel engines, stored into 6,202 litres (219 ft3) tanks, used when the sub surfaced, CT broaching. Two low-pressure blowers Reavel-Cerpelli worked at 1.7 atm. for 30 m3, these blowers sharing the same electric motors, able to move 60 tons of water per hour. Emergency saw the pumps used to launch torpedoes, capable of 30 tons per hour and capable of also moving ballast water. This was rounded up by emergency pumps also driven by low-pressure air or hand-operated for 120 litres per hour (4.238 ft3/h). There was also an air regeneration system for the removal of CO2 and oxygen tanks. The remainder of the internal facilities was the same as other Bernardis designs.

Armament

It was a repeat of the Bandiera class, the Squalo had eight internal 53.3 cm (21 in) torpedo tubes, four bow, four stern. A dozen torpedoes were in store, less the eight already preloaded in the tubes. They were also armed with a single 102 mm (4 in) OTO m1931 deck gun for surface attacks, with an anti-aircraft defence of two 13.2 mm (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 Squalo 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 Silurificio Whitehead di Fiume common A140/450 (1921). Capable of 29-32 knots, 6,000-4,000 m range settings, 1,140 Kgs, TNT warhead 140 kg, air tank loaded to 170 atmospheres. It was however quite visible due to the compressed air bubble trail, especially in calm waters.
Later in 1933-36 it was probably given the following wet-heater models:
-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.

Dedicated illustration planned

⚙ Squalo specifications
Displacement	920t surfaced, 1,125t submerged
Dimensions	69.8 x 7.21 x 5.19 m (229 x 23 ft 8 in x 17 ft)
Propulsion	2 shafts diesel FIAT 3,000 bhp (2,200 kW), 2 electric motors 1,300 bhp (970 kW)
Speed	15.1 knots surfaced, 8 knots submerged
Range	5,650 nmi at 8 kts surfaced, 100 nm at 3 kts underwater
Armament	8× 533 mm TTs (4 bow, 4 stern), 102 mm deck gun, 2× 13.2 mm AA
Max test depth	90 m (300 ft)
Crew	53

Assessment

During the Second World War, they operated in the Mediterranean with very poor results. The sinking by Delfino, of the neutral Greek light cruiser Elli and some presumed damage, was everything she had to show for. Tricheco accidentally sank the Italian submarine Gemma. Given their size, much larger than the previous 600t class, but too small to operate in the Atlantic, they were eventually used as supply transport to North Africa. Narvalo was lost on this route by British aircraft and vectored in destroyers. Only Squalo, survived the war, on paper par tof the co-belligerence, but she had no crew and was, by all means, inoperative after September 1943.

Career of the Bandiera class

Delfino

Delfino (dolphin) was laid down on 27 October 1928 at CRDA, launched on 27 April 1930, completed on 19 June 1931. She made long cruises to the Black Sea in 1933, and the eastern Mediterranean in 1934. By December 1936 she patrolled the eastern coast of Spain (Spanish Civil War) and missed a merchant ship suspected to bring weapons to the Republicans. In 1937 after the second Italo-Ethiopian War, like ehr sisters she was sent in the Red Sea at Massawa and returning to Messina in 1938.
By June 1940, Delfino was based in the Aegean Sea. On 15 August she took part in a serious diplomatic incident when she torpedoed and sank the neutral “cruiser” Elli at anchor off Tinos for the Virgin Mary celebrations, acting as honour guard. This was compounding by this Holy day, also for Catholic Italians, just like Orthodox Greeks. Italy’s Foreign Minister, Count Ciano later said this was ordered by Mussolini to intimidate the Greeks, still neutral. However, by April 1940 Greece accepted British guarantees and the Italian government denied Greek accusations. They later recovered fragments of the torpedoes, proved them to be Italian, notably to the British. This strengthened the will of the Greeks to refuse the Italian ultimatum two months later. Postwar they received as was reparation the ex Italian cruiser Eugenio di Savoia, renamed …Elli.
On 29 November 1940 while in the northern Aegean, Delfino fired two torpedoes at a Greek convoy, reporting Psara hit, but never confirmed. On 1 August 1941 while off Tobruk she was spotted and attacked by a Short Sunderland of 230 Squadron. Still she managed to shoot it down, even rescuing four men from a total of twelve. She then led patrols around Sicily and Malta. From February 1942 however, her military value and age force Supermarina to reassign her to the Submarine School at Pola only for advanced training. In November 1942 she returned to full combat service, based at Taranto. She was stripped of her torpedoes to conduct transport missions to North Africa, carrying 200 tons of ammunition and fuel. She was refitted between January and March 1943 and on the 23th, she sank just an hour after leaving Taranto, colliding with her own escort boat. Being surfaced at the time, 28 crew trapped inside went down, the remainder jumped overboard and were rescued.

Narvalo

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Narvalo after entering service was stationed in La Spezia and joined II ‘Medium-Cruise Submarine Squadron”. In 1931 she had drills off the Sardinian coast and made a cruise to the eastern Mediterranean. Her base was moved to Naples in 1934, reassigned to the IV Squadron, then Tobruk, and then Massawa, with operation cycles in 1935-36 and 1938, showing her expected good operational qualities in warm waters. Next she was sent to Fiume by December 1938, and 23rd Squadron in Messina. In 1939, she was sent to the Submarine School in Pola. In June 1940 she was transferred to the 5th Group of Leros, reaching it on January 22, 1940, and she operated in the Eastern Mediterranean.
On the night of September 27-28, 1941 under Lieutenant Giuseppe Caito she attacked a cargo ship off Cape Bon, firing two torpedoes but missing.
On December 14 she was attacked by escorts near Cape Passero, badly damaged, forcing her back to base for repairs.
In the spring of 1942 she was reconverted to transport supplies to Libya, a total of eight missions with a total of 510.3 tons of supplies, 70.7 tons of fuel and lubricant cans, 404.7 tons of ammunition, 25 tons of provisions, 9.9 tons of other cargo. On the evening of January 13, 1943 after her 8th transport mission she left Tripoli under Lieutenant Ludovico Grion for Italy. Aboard were 11 British officers taken prisoner and five Italian soldiers guarding them, plus six other Italian soldiers repatriated in addition to the crew.
Then at 1:45 PM the following day a British aircraft spotted her, attacked her 140 miles southeast of Malta. She dropped a depth charge which hit her, disabling her diesels, decoupling the shaft lines. She was immobilized, unable to submerge or sailing further. Commander Grion ordered scuttling preparations when two British destroyers, HMS Hursley and Pakenham, informed by the aircraft, arrived on the scene. They opened fire, and savaged her. Narvalo sank quickly with four officers, 25 petty officers and sailors, 11 Italian soldiers, 8 British officers but 32 crew and 3 prisoners were rescued. In all, Narvalo performed 23 combat patrols, 8 transport missions, 5 transfers over 20,760 miles surfaced, 3020 submerged.

Squalo

Once in service, Squalo was deployed to La Spezia, joining the II Medium Cruise Submarine Squadron. From 1934, she formed the IV Submarine Squadron in Naples with her sister ships. In 1936 she was assigned to the Eritrean base of Massawa, performing training missions to test her performance in warm waters until January 1938 and was sent back to Italy to join the 23th Submarine Squadron in Messina. From 1940 she operated in the eastern Mediterranean, based at Leros under command of Lieutenant Giuseppe Migeca. No sorties brought any success.
On July 23, 1941 under Lt. Ludovico Grion she laid in ambush near the coast of Cyrenaica and moved to the north of Ras Azzaz. She spotted there a large tanker sailing west, fired two torpedoes from 1000 m and heard two loud explosions, but the tanker, probably damaged, survived and vanished in fog and darkness.
On July 30, 1941, she was attacked by two destroyers south of Crete but escaped. In September 1941, she headed for the Sardinian coast to counter Operation Halberd after Supermarina believed this was a mission against the Italian coast. On 29 September and 19 December 1941, she laid in ambush off Malta, but was attacked by escort destroyers, emerging unscathed.
In total, she made 28 sorties and 14 transfers over 18,800 miles (2,754 miles submerged) until 30 April 1942. From 1 May 1942 to early September 1943 she made 121 training missions with a few defensive ambushes in the northern Adriatic where she remained, based at the quiet Pola Submarine School. On 7 September 1943 under Lieutenant Carlo Girola she was ordered to the Ionian Sea as part of Operation Zeta, to defend the coast against an allied landing.
On 10 September with the armistice she was ordered to Augusta and departed on the 16th with five other submarines for Malta, remaining submerged to avoid allied attacks. By 13 October, she left Malta back to Italy after a proper surrender and swap to the allies. From 20 November she was based in Augusta, and she started co-belligerence missions from 20 January 1944, like many of her sisters, for ASW exercises under Alfredo Fellner and Fernando Ubaldelli until decommissioned in May 1945, placed in reserve until stricken on 1 February 1948 and BU.

Tricheco

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Tricheco (Walrus) was ordered from CRDA, laid down on 10 November 1928, launched on 11 September 1930 and commissioned on 25 June 1931. After entering service, she was assigned to the SubRon in La Spezia. On 16 January 1931, she collided with a fishing vessel, was damaged and repaired. On 3 November 1933, the casing of one of her diesels exploded, causing a fire, quickly extinguished. In 1934, one of the periscopes was damaged when she hit a crane. From 1 May to 18 June 1933 under command of Lt. Cdr Giacinto Poggio she made a cruise with Delfino in the Black Sea, stopping at Batum, Constanta, Varna, and Istanbul, test conditions for crossing the Dardanelles. In 1934 he was assigned to Naples’s IV Squadron. From August 1935 she was deployed to Massawa in the Red Sea under command of Costanzo Casana. Lieutenant Junio Valerio Borghese was on board as 2nd Squadron Commander. They were back home on August 1936.
She clandestinely took part in the Spanish Civil War under command of Benedetto Luchetti from 17 to 29 August 1937 north of Pantelleria and back to Messina, attempting a single attack, aborted. In 1938, she was assigned to SubRon 23 based in Messina but returned several times to Fiume several times for training. Later this was the V Group in Leros.
In June 1940 she made an unsuccessful mission 20 miles east of Punta Castello and back to Leros on 14 June. From 19 to 23 June, she operated north of Crete. On 3 July, she took positions between Alexandria, and Cape Kupho in Crete to protect the flank of an Italian convoy. On the 9th she spotted a ship but was unable to get within range.
She was deployed later to the Kaso Channel in Greece from 6 to 16 August 1940. She was forced back to Leros early after a serious injury on board on 8-9 October 1940 under Lt. Alberto Avogadro di Cerrione. Furthermore, she was soon involved in a tragic friendly fire incident while in the Caso Channel, spotting what was believed an enemy submarine, launching two torpedoes and it at 1.21 am, what was later reported as Gemma, whose presence in that area was unknown to Tricheco’s commander. It is not sure a challenge was made. She was suspected enemy from the start. There were no survivors. From 29 October to 5 November she made a patrol near Gaudo, 150 miles from Alexandria. Again, no spot, no kill.
On May 8, 1941, she was in an ambush mission in the Gulf of Taranto. On May 19-23, she layed in ambush 30 miles from Ras Uleima, Gulf of Sollum.
On September 25, under Lt.Cdr. Carlo Gandolfo, she was posted 60 miles from Ras Aamer. No spot, no kill. On October 7, while back to Augusta, she was attacked by a Bristol Blenheim and crash-submerged, but not before hitting the bomber, which went back to its airfield.
At 11:47 on November 29 Cdr. Alberto Campanella spotted a formation of 4 British cruisers, 2 destroyers while patrolling in the Central Mediterranean and launched an attack with three torpedoes against the cruiser, but most likely missed and nothing was reported on the British side. In early February 1942, she counted Operation “MFS” and was sent off the coast of Cyrenaica to assist the submarine Dandolo, dead in the water, on 21 February.
At 5:30 pm on 18 March 1942, under Lt.Cdr. Giovanni Cunsolo underway from Augusta to Brindisi for a refit, she was ambushed by HMS Upholder, taking a torpedo hit just amidship. She broke in two and sank rapidly not far from Brindisi. Lt. Ermanno Tonti, XO, 10 petty officers and 27 petty officers and sailors went down but Cdr. Cunsolo and 10 men were saved, being in the CT or the deck. In total “walrus” performed 13 combat patrols, 6 transfers over 12,435 miles surfaced and 2,678 submerged. Her wreck was located in 2006, 3 miles from the shore under 72-80 metres, lying on the seabed on her right side, silted up with many nets entangled.