Argentina’s “Heavy” Cruisers
By Mike Bennighof
March 2012

In the 1920s, two types of cruiser became the standard for world navies: the 10,000-ton “heavy cruiser” armed with 8-inch guns, and the “light cruiser,” usually smaller, armed with 6-inch guns. With those characteristics defined by naval limitations treaties, ship designers had little variance in their work.

The Italian Orlando combine was one of the few conglomerates to design ships outside the treaty standards. Italian designers focused on the export market, seeking contracts with foreign powers that had not signed any of the naval treaties and so were not bound by their limits. These “export cruisers” were smaller than the treaty-mandated heavy cruisers, and carried non-standard 190mm (7.5-inch) guns. All these measures were designed to save costs, to make the ships attractive to less wealthy customers.

Big sister: RN Trento, 1936.

The program eventually attracted three customers. Siam bought two small cruisers based on the Montecuccoli-class light cruiser design. The Soviet Union contracted the Italian firm to design their Kirov-class “heavy” cruisers with 180mm (7.1-inch) guns but after negotiations to construct the lead ship of the class in Italy, decided to build all of them at home with Italian assistance.

Argentina, a longtime customer of Italian yards, ordered two of these “in between” ships in 1926 as the centerpieces of a 75 million peso naval program. Their design derived from the Italian Trento-class heavy cruiser, a very fast ship but one with minimal protection.

Launched in 1929, both ships commissioned on 5 July 1931. Almirante Brown and 25 de Mayo displaced 6,800 tons standard and 9,000 tons at full load; Trento (built on the same slip as 25 de Mayo) came in at 10,300 standard and 13,300 full load. The Argentine ships were 20 meters shorter than their Italian semi-sister, without Trento’s second funnel or X position (aft superfiring) gun turret.

The Argentine cruisers carried six 7.5-inch guns, and a dozen of the 100mm anti-aircraft guns standard on Italian cruisers of the period. They had six fixed torpedo tubes and, like Trento, a bow-mounted gunpowder catapult for a seaplane (unlike Trento, the Argentine cruisers carried British- or American-made planes during their service life).

Jane’s Fighting Ships, the influential annual publication, roundly criticized the ships. They made only 32 knots compared to Trento’s 36, had even weaker armor protection than the Italian ship and (though Jane’s did not know this) the same horrific gunnery limitations as Trento: The Oderno-Terni 190mm gun did not have flashless charges and so could not be used at night without revealing the ship’s position. Fortunately, the Argentine crews did not have to learn this tactical limitation under fire, as would happen to three Italian cruisers in 1941. The two Argentine cruisers did have much better cruising range than the Italian ship.

Despite these apparent limitations, the Argentines were well pleased with their purchases. The cruisers made numerous good will visits to South American ports. In 1936, 25 de Mayo and the destroyer Tucuman sailed to Spain to represent Argentine interests during the Civil War — the only time Latin American warships have exerted “gunboat diplomacy” in European waters. The two ships evacuated 1,825 Argentine citizens over their five-month deployment.

ARA Almirante Brown.

Both cruisers participated in Argentina’s 1947-48 “Antarctic Campaign,” nearly becoming involved in a gunnery action with the British cruiser Nigeria in late 1947. Though the cruisers remained very seaworthy and had been well-maintained, modernization would have been very expensive. In January 1951 Argentina acquired a pair of American Brooklyn-class light cruisers at the bargain price of $4 million apiece. These ships greatly outclassed the small Argentine cruisers, and to the horror of Argentina’s leaders, their rivals Chile and Brazil had also been sold two of them each as well.

Argentine naval policy for over half a century had followed the formula “A = B+C”: Argentine naval strength had to equal the combined power of both Chile and Brazil. The American sales overturned this ratio. Some Argentine naval leaders seethed that the Americans had mislead them. The Brooklyn class comprised eight surviving ships in 1951, and they expected to be granted four of them while their rivals received two each, keeping the precious balance of power in the Southern Cone.

25 de Mayo during her Spanish deployment, 1936.

Denied their sacred ratio, the Argentine Navy instead initiated a series of design studies for conversion of the two Almirante Brown-class cruisers into small aircraft carriers similar to the American Independence class. Their hulls and machinery passed inspection, and this use seemed more cost-effective than installing the major systems upgrades of the post-war world.

The work appeared beyond the means of Argentina’s limited shipbuilding capacity, and in the 1950’s surplus British and American purpose-built aircraft carriers flooded the world marketplace. Though the Argentines burned at the thought of depending on Anglo-American good will for their naval needs, they eventually abandoned the conversion plan. After inspecting the British fleet carrier Indefatigable, the Argentines blanched at her maintenance and refit costs and settled for the much smaller former British light carrier Warrior.

The two “heavy” cruisers, now rapidly aging, went back to Italy in 1962 on a final voyage, and were scrapped there. They had never fired a shot in anger, but projected Argentine power in the Atlantic, Pacific and Mediterranean and been accounted as great successes by their owners.

Both cruisers appear in Cone of Fire, in scenarios pitted against Chilean, Brazilian, German and British warships. Though listed as heavy cruisers (type “CA”) they are no match for most “Treaty cruisers.”

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