Duca degli Abruzzi class cruisers

Regia Marina – Light Cruisers (1936) Duca degli Abruzzi, Garibaldi

The last Condottiere: This class also counting the Guiseppe Garibaldi was built by OTO shipyards in La Spezia, the lead ship being named after Luigi Amedeo, Duke of Abruzzo, Italian explorer and Admiral of the First World War. The Duca degli Abruzzi class cruisers were the final version of the long-standing Condottieri class and were larger and better protected than their predecessors.

Abruzzi doing her sea trials, 1938

About the Condottieri class

Understanding the “Condotierri” class and its evolution is knowing about Italian cruisers during the last war. Under this generic name roughly meaning “mercenary general”. This is a reference to Renaissance wars in Italy, but the term was kept to describe successful general/statesmen, and indeed this superclass of 10 ships was often named after these historical figures. On paper, they were all light cruisers, aside the heavy cruiser classes, namely the Trento and Zara class.

The first four ships (Guissano) of 1928 were very close to the next pair (Cadorna) in size, armament and tonnage. However, the following three pairs were much larger, jumping from 6000 to nearly 10,000 tons. These were the new generation treaty cruisers, redefined by the treaty of London and putting the emphasis on more light artillery and speed. The Montecuccoli and Aosta were near-sisters, but the last pair, simplified as “Abruzzi” or often named the Garibaldi class, introduced a number of new features.

They appeared in 1937, when the first of the Litorrio new superdreadnought class and the rebuilt Duilio class battleships were introduced to the Regia Marina, equipped with a new generation of secondary armaments. There has been no successor program to the Condottieri, although a sixth group was ordered and studied but none was firmly ordered. This would have been the “Ciano class” (see later).Design of the Abruzzi

In short, the two cruisers were slightly larger than the last four ships, and their armament was augmented by two additional 152 mm guns in triple turrets at positions A and Y. The powerplant was also fully revised, allowing greater reliability but at the cost of a slightly lower maximum speed than their predecessors. The first of the two cruisers was completed in 1937, forming the 8th Cruiser Division.

General specifications

Both cruisers displaced slightly more than designed (as customary) at 11,350 tons standard and 11,735 tons fully loaded, to compare with the relatively similar third group Montecuccoli at 7,523 t (7,404 long tons) standard for 8,994 t (8,852 long tons) fully loaded. This was however only 1500 tons more than the fourth group d’Aosta (the displacement of an average destroyer). This increase was explained by the greater beam (1.30 m), additional armor as well as the two additional guns, making larger turrets, wells, and ammunition holds. Dimensions remained the same at least for the length, 171.1 at the waterline and 187 m (561–614 ft) overall, for a beam however of 18.9 m (62 ft) – compared to D’Aosta’s 17.5m (57.7 feets) and a draught of 6.9 m (23 ft), also an increase of about 50 cm.

Installed power and performances

The powerplant was not anemic, with a whopping 100,000 hp (75,000 kW), less however than the 110,000 hp of her predecessor. The two shafts connected to Belluzzo/Parsons geared turbines were fed by six oil-firing Yarrow boilers.
Top speed fell to 34 knots (63 km/h; 39 mph) (62 km/h) compared to 36.5 knots (67.6 km/h; 42.0 mph) on d’Aosta. Range was better however at 4,125 nmi (7,640 km; 4,747 mi) at 13 kn (24 km/h; 15 mph) compared to 3900 nautical miles due to an increase in oil storage also used as an additional buffer for ASW hits.

Armament

That’s by far the most interesting part of the design. For the first time, Italy joined the “triple turrets” club on cruiser design, like UK, France, USA and Japan in the wake of the Treaty of London. One can wonder why the ships did not adopted straight away a four triple scheme like the contemporary Southampton class, but one must remember the prime rival in these waters was France, which developed the Bertin and La Galissonière class with three triple turret, or nine guns. By compromising with twin and triple turret design (the latter been untested yet), the Italians still had the advantage of ten guns while allowing some teething adjustments. However let’s recall that the next class Ciano was still armed the same way.

These 152 mm guns (6-in) were the caliber 55 naval gun Model 1936. They were used also as secondary artillery on the Littorrio class battleships. The 1936 version made by OTO Melara were constructed of two tubes, a loose liner and a horizontal sliding breech block. They fired quick firing separate loading ammunition. Traverse, elevation and other functions were performed electrically. Loading was made by telescopic pneumatic rammers. Loading could be done at +20° while elevations ranged from -5° to +45°. Rate of fire was 4-5 rpm, muzzle velocity 910 m/s (3,000 ft/s) with a 50 kilograms (110 lb) HE or AP shell, with a maximum firing range of 25.7 kilometers (16.0 mi) at +45°.

Secondary artillery comprised four twin mounts 8 x 100 mm (4 in) / 47 caliber guns (OTO 1937 100/47). Made by OTO on the model 1928 they were based on the 1910 the WW1 Škoda 10 cm K10 (also used by the Russians since their cruisers were Italian designed). They had a horizontal sliding breech block and an elevation range from -5° to +85°.  Rate of fire was 8-10 rpm, firing a 15.2 km (9.4 mi) at 45° with a AA Ceiling of 10 km (33,000 ft) at 80° at a muzzle velocity of 880 meters per second (2,900 ft/s). Tertiary AA armament comprised eight 37 mm (1.5 in) 54-cal. guns and during the war twelve 20 mm (1 in)/65 caliber were added.

The first were Breda classic twin mounts. These automatic, gas operated guns fired a fixed ammunition QF 37 x 232mm SR HE weighting 1.25–1.63 kg (2 lb 12 oz–3 lb 9 oz). Elevation was −10° to +80° for a 60-90-120 rpm at 800 m/s (2,600 ft/s). Effective firing range 4,000 m (4,400 yd) up to 7,800 m (8,500 yd). The 20 mm AA guns were the single gas-operated Breda Model 35, with an elevation of -10 degrees to +80, 240 rpm, firing a 20×138mmB HE shell at 840 m/s (2,800 ft/s). For close quarters, they were two triple banks of 533 mm torpedo tubes. Complement also comprised four Ro.43 planes.

IMAM Ro.43 (1936) based on the Ro37 terrestrial observation aircraft, the standard observation and fighter aircraft of the fleet until 1943, agile but slow. Four were carried, two stored, wings folded in a hangar, two on side catapults each side of the rear funnel.

Protection

The Abruzzi Outer Belt was 30 mm (1.2 in), inner Belt 100 mm (3.9 in). The main Deck protection was 40 mm (1.6 in) down to 10–15 mm (0.39–0.59 in) on the upper deck. The turrets were protected by 135 mm (5.3 in) frontal armor, the barbettes 30 mm up to 100 mm (1.2–3.9 in). The Outer Bulkheads were 30 mm (1.2 in) and behind was an inner layer of 100 mm (3.9 in), whereas the conning Tower protection ranged from 30 mm (roof) to 140 mm (1.2–5.5 in) for the walls.