Brooklyn-class cruiser

The Brooklyn-class cruiser was an American light cruiser class of the Second World War, famous for its main battery of fifteen 6-inch guns in five triple turrets, the heaviest broadside of any light cruiser of its time. Nine ships were built between 1935 and 1938, and they served in the Atlantic, the Mediterranean, and the Pacific, fighting in the battles of Casablanca, Sicily, Salerno, Anzio, Normandy, and the Philippines. The class was one of the most successful light cruiser designs of the war, and its ships served after the war with the navies of Argentina, Brazil, and Chile into the 1980s. The Brooklyn class showed that a light cruiser, properly armed and well handled, could be as effective as a heavy cruiser.

1. Key Facts

Field	Value
Type	Light cruiser
Country	United States
Designer	US Navy Bureau of Construction and Repair
Production	1935–1938
Number built	9
Displacement	9,767 tons standard; about 12,207 tons full load
Length	185.4 metres (608 ft 4 in)
Beam	18.8 metres (61 ft 7 in)
Draught	6.0 metres (19 ft 8 in)
Propulsion	Steam turbines, 100,000 shaft horsepower, 4 shafts
Speed	32.5 knots
Range	About 10,000 nautical miles at 15 knots
Complement	About 868 officers and men (wartime up to 1,200)
Main armament	15 × 6-inch (152 mm) guns in 5 triple turrets
Secondary armament	8 × 5-inch (127 mm) guns
Anti-aircraft armament	28 × 40 mm Bofors; 20 × 20 mm Oerlikon (wartime)
Aircraft	4 × floatplanes, 2 catapults
Armour	Belt 3.25–5 inches; deck 2 inches; turrets 6.5 inches
Main theatres	Atlantic, Mediterranean, Pacific 1941–1945

2. Origins and Development

The London Treaty and the Light Cruiser

The Brooklyn class was developed under the London Naval Treaty of 1930, which limited heavy cruisers to 8-inch guns and light cruisers to 6-inch guns, and which encouraged navies to build light cruisers with a large number of 6-inch guns. The United States Navy, which had built heavy cruisers in the 1920s, decided to build a light cruiser with fifteen 6-inch guns, the maximum that could be carried on a 10,000-ton hull, and the Brooklyn class was the result. The class was designed to be fast, well protected, and heavily armed, with a main battery that could outgun any other light cruiser in the world. The Brooklyn class was a response to the Japanese Mogami class, which also carried fifteen 6-inch guns, and it showed that the United States could match Japan in cruiser design.

Design and Construction

The Brooklyn class was 185.4 metres long, 18.8 metres wide, and displaced 9,767 tons standard and about 12,207 tons at full load. Her steam turbines produced 100,000 shaft horsepower, driving four shafts, and gave her a top speed of 32.5 knots. Her armour belt was 3.25 to 5 inches thick, her deck was 2 inches, and her turrets were protected by 6.5 inches of armour, which gave her good protection against 6-inch shells and against bombs. Her main battery was fifteen 6-inch guns in five triple turrets, three forward and two aft, which gave her a broadside of fifteen guns, the heaviest of any light cruiser. The class was built by five shipyards, including the New York Navy Yard, the Philadelphia Navy Yard, and the Newport News Shipbuilding Company, and the first ship, USS Brooklyn, was commissioned in September 1937.

The Nine Ships

Nine Brooklyn-class cruisers were built between 1935 and 1938: Brooklyn, Philadelphia, Savannah, Nashville, Phoenix, Boise, Honolulu, St. Louis, and Helena. The last two ships, St. Louis and Helena, were built to a slightly modified design, with a different machinery arrangement and a different superstructure, and they are sometimes considered a separate sub-class. The nine ships were named for American cities, and they served in the Atlantic and the Pacific Fleets before the war, taking part in fleet exercises, in the Neutrality Patrol, and in the occupation of Iceland. When war broke out in December 1941, the Brooklyn class was immediately available, and its ships were among the first American cruisers to see combat.

The St. Louis Sub-Class

The St. Louis sub-class, comprising USS St. Louis and USS Helena, was built with a unit machinery system, in which the boilers and the turbines were arranged in separate compartments, so that a single hit could not disable the whole plant. This was an important improvement, because it made the ship more survivable, and it was later adopted for all American cruisers. The St. Louis sub-class also had a different superstructure, with a single funnel instead of two, and a different anti-aircraft battery. The two ships served with distinction in the Pacific, where Helena was sunk at the Battle of Kula Gulf in July 1943, and St. Louis survived the war and served in the Brazilian Navy as Tamandare. The St. Louis sub-class showed how a successful design could be improved during production.

3. Technical Design

Hull, Machinery, and Speed

The Brooklyn class was a long, narrow ship, built for speed, with a hull that was 185.4 metres long and a machinery plant that produced 100,000 shaft horsepower. Her top speed of 32.5 knots made her one of the fastest cruisers of her time, and her range of about 10,000 nautical miles at 15 knots gave her the endurance for operations in the Pacific and the Atlantic. Her crew of about 868 officers and men, rising to 1,200 in wartime, was well trained and experienced, and her habitability was good by the standards of the time. Her hull was strong and well built, and it could survive damage that would have sunk a smaller ship, as the class proved at Casablanca, Salerno, and Kula Gulf, where several ships were hit by torpedoes and bombs and survived.

Main Battery and Fire Control

The main battery of the Brooklyn class was fifteen 6-inch/47 guns in five triple turrets, three forward and two aft, controlled by a Mk 34 fire-control system with a Mk 8 radar, which allowed the ship to engage surface targets at long range and in bad weather. The 6-inch gun could fire a 47-kilogram shell to a range of about 23 kilometres, and it could fire eight to ten rounds per minute, which gave the Brooklyn class a broadside of 120 to 150 rounds per minute, the heaviest of any light cruiser. The fire-control system was one of the best in the world, and it allowed the Brooklyn class to bombard shore targets with great accuracy, and to engage enemy surface ships at long range. The main battery was the heart of the ship, and it was the reason why the Brooklyn class was so effective in the Mediterranean and the Pacific.

Secondary and Anti-Aircraft Armament

The secondary armament of the Brooklyn class was eight 5-inch/25 guns, later replaced by 5-inch/38 guns, which could fire at aircraft and at surface targets, and which gave the ship a useful anti-aircraft battery. The anti-aircraft armament was increased during the war, with the addition of twenty-eight 40-millimetre Bofors guns and twenty 20-millimetre Oerlikon cannon, which gave the ship a strong defence against aircraft. The Bofors gun was the best light anti-aircraft gun of the war, and the Brooklyn class carried a large number of them, which made it effective against German and Japanese aircraft. The ship also carried four floatplanes, launched from two catapults, which were used for reconnaissance and for spotting the fall of shot, though they were rarely used in combat after 1944, when radar had made them less necessary.

4. Service in the Atlantic and the Mediterranean

Casablanca and North Africa

The Brooklyn class first saw combat in the Atlantic and the Mediterranean, where its ships took part in the invasion of North Africa, Operation Torch, in November 1942. USS Brooklyn, USS Philadelphia, and USS Savannah bombarded the French defences at Casablanca, Fedala, and Safi, and they fought the French battleship Jean Bart and the French cruisers and destroyers, silencing their guns and supporting the landings. The class performed well in its first combat, and it established a reputation for accurate gunfire and for fighting spirit. The Brooklyn-class cruisers served in the Mediterranean for the whole of the North African campaign, screening convoys, bombarding shore targets, and protecting the invasion fleet against air attack.

Sicily, Salerno, and Anzio

In 1943, the Brooklyn class took part in the invasion of Sicily, Operation Husky, where its ships bombarded the beaches before the landings, and in the invasion of Italy at Salerno, Operation Avalanche, where they provided fire support for the troops ashore. At Salerno, USS Savannah was hit by a German Fritz X guided bomb, which killed more than 200 of her crew, but she survived and was repaired, a testament to the toughness of the class. At Anzio in January 1944, the Brooklyn-class cruisers bombarded the German positions and supported the landings, and they remained off the beachhead for weeks, providing fire support under constant air attack. The Mediterranean service of the Brooklyn class was the most important of its career, and it showed that the light cruiser, with its rapid-fire 6-inch guns, was ideal for shore bombardment.

Normandy

In June 1944, the Brooklyn-class cruisers took part in the Normandy landings, Operation Neptune, where USS Philadelphia, USS Boise, and USS Augusta bombarded the German defences on Omaha and Utah beaches, and where they supported the troops ashore. The class fired thousands of 6-inch shells at German positions, silencing guns, destroying strongpoints, and supporting the advance inland. The Normandy landings were the largest amphibious operation in history, and the Brooklyn class played a central part in them, providing the fire support that the infantry needed to get ashore. After Normandy, the class served in the Mediterranean and the Atlantic for the rest of the war in Europe, and its ships were among the most decorated cruisers of the war.

5. Service in the Pacific

The Solomons and the Philippines

In the Pacific, the Brooklyn class served in the Solomon Islands, where its ships fought in the battles of Kula Gulf, Kolombangara, and Empress Augusta Bay, and where they screened carriers and bombarded Japanese-held islands. USS Helena was sunk at the Battle of Kula Gulf on 6 July 1943, after being hit by three Japanese torpedoes, with the loss of 168 of her crew, the only Brooklyn-class cruiser lost in the war. USS Honolulu, USS St. Louis, and USS Nashville served in the Solomons and in the Philippines, where they bombarded Japanese positions and supported the landings at Leyte, Luzon, and Mindoro. The Pacific service of the Brooklyn class was hard and dangerous, but it showed that the light cruiser could fight surface actions as well as bombard shore targets.

The End of the War

By 1945, the Brooklyn-class cruisers in the Pacific were among the most experienced ships in the Navy, and they took part in the final operations of the war, including the bombardment of Japan and the occupation of Tokyo Bay. USS Nashville carried General Douglas MacArthur to the Philippines, and USS Boise served in the occupation of Japan. The class earned many battle stars for its service in the Pacific, and its ships were decorated for their service. The Brooklyn class served in every theatre of the war, from the Atlantic to the Pacific, and it was one of the few cruiser classes to do so. Its service in the Pacific was the culmination of a career that had begun in the Mediterranean and the Atlantic, and it showed the versatility of the design.

6. Strengths

Firepower and Rate of Fire

The greatest strength of the Brooklyn class was its firepower, because fifteen 6-inch guns, firing eight to ten rounds per minute each, gave it a broadside of 120 to 150 rounds per minute, the heaviest of any light cruiser in the world. The 6-inch gun was ideal for shore bombardment, because it could fire rapidly and accurately, and it could destroy bunkers, guns, and strongpoints, and it was also effective against surface ships, because its high rate of fire could overwhelm an enemy. The Brooklyn class was a ship that could put a great weight of shell on a target in a short time, and it was trusted by the Army and the Marines, who depended on its fire support. Its firepower was the reason why it was used in every major landing of the war.

Speed, Protection, and Versatility

The Brooklyn class was fast, with a speed of 32.5 knots, well protected, with a belt of 3.25 to 5 inches and a deck of 2 inches, and versatile, because it could screen carriers, bombard shore targets, fight surface ships, and escort convoys, and it did all of these jobs well. Its speed allowed it to operate with the fleet, and its protection allowed it to survive damage that would have sunk a smaller ship. Its versatility was shown by its service in the Atlantic, the Mediterranean, and the Pacific, in roles that ranged from shore bombardment to surface combat to carrier screening. The Brooklyn class was a cruiser that could do everything, and it was one of the most successful light cruiser designs of the war.

7. Weaknesses

Vulnerability to Torpedoes and Bombs

The main weakness of the Brooklyn class was its vulnerability to torpedoes and to guided bombs, because its armour, though good for a light cruiser, could not stop a torpedo or a Fritz X bomb. USS Helena was sunk by torpedoes at Kula Gulf, USS Savannah was badly damaged by a Fritz X at Salerno, and USS Honolulu was torpedoed at Kolombangara, though she survived. The class was also vulnerable to air attack, because its anti-aircraft guns, though numerous, could not stop every attacker, and several ships were hit by bombs and by kamikaze aircraft. These were weaknesses shared by every cruiser of the period, but they were real, and they showed that the light cruiser, for all its firepower, was still a vulnerable ship.

Age and the Post-War Navy

The Brooklyn class was built in the 1930s, and by the end of the war it was showing its age, with worn machinery, crowded accommodation, and an anti-aircraft battery that was no longer adequate against jet aircraft. The class was retired by the United States Navy in the late 1940s and early 1950s, and its ships were sold to Argentina, Brazil, and Chile, where they served into the 1980s. The Brooklyn class was a superb gun cruiser, but it was a product of its time, and its time had passed by the 1950s, when the missile cruiser had arrived. Its retirement was the end of an era, the era of the big-gun light cruiser that had begun in the 1930s.

8. Notable Ships

USS Brooklyn and USS Philadelphia

USS Brooklyn, CL-40, was the lead ship of the class, commissioned in September 1937, and she served in the Atlantic and the Mediterranean, earning four battle stars, and she was sold to Chile in 1951, where she served as O’Higgins until 1992. USS Philadelphia, CL-41, served in the Atlantic and the Mediterranean, earning five battle stars, and she was sold to Brazil in 1951, where she served as Barroso until 1974. USS Savannah, CL-42, served in the Mediterranean, where she was hit by a Fritz X at Salerno, and she earned three battle stars, and she was sold for scrap in 1966. These ships were among the most distinguished of the class, and they are remembered for their service in the Mediterranean and the Atlantic.

USS Phoenix, USS Boise, and USS Helena

USS Phoenix, CL-46, served in the Pacific, earning nine battle stars, and she was sold to Argentina in 1951, where she served as General Belgrano, and she was sunk by the British submarine Conqueror in the Falklands War in 1982, with the loss of 323 men, one of the most controversial sinkings of the war. USS Boise, CL-47, served in the Mediterranean and the Pacific, earning eleven battle stars, and she was sold to Argentina in 1951, where she served as Nueve de Julio until 1978. USS Helena, CL-50, served in the Pacific, earning seven battle stars, and she was sunk at Kula Gulf in 1943, the only ship of the class lost in the war. The Brooklyn class served with distinction in every theatre, and its ships are remembered for their service in three wars and in the navies of four countries.

9. Legacy

Long Service in Foreign Navies

The legacy of the Brooklyn class is its long service in foreign navies, because its ships served with Argentina, Brazil, and Chile into the 1970s and 1980s, and one of them, the former Phoenix, served as the Argentine cruiser General Belgrano, which was sunk in the Falklands War in 1982. The class was a successful export, because it was well built, well armed, and easy to maintain, and because it could be modernised with new weapons and electronics. Its long service showed that a good cruiser design could remain useful for decades, and that it could serve in the navies of many countries. The Brooklyn class was one of the longest-serving cruiser designs of the Second World War.

Influence on Cruiser Design

The Brooklyn class influenced the design of later American light cruisers, notably the Cleveland class, which was a Brooklyn with a different machinery arrangement and a heavier anti-aircraft battery, and which became the largest cruiser class in history, with 27 ships built. The Cleveland class used the Brooklyn hull as its starting point, and it showed how a successful design could be improved and adapted for new roles. The Brooklyn class is remembered as one of the best light cruiser designs of the Second World War, and as a ship that served its country in every theatre of the war and in the navies of three other countries for another forty years.

Frequently Asked Questions

What is the Brooklyn-class cruiser?
It is an American light cruiser class of the Second World War, with fifteen 6-inch guns in five triple turrets, a speed of 32.5 knots, and a displacement of about 9,767 tons standard.

How many Brooklyn-class cruisers were built?
Nine were built between 1935 and 1938, named for American cities: Brooklyn, Philadelphia, Savannah, Nashville, Phoenix, Boise, Honolulu, St. Louis, and Helena.

Where did the class serve in the Second World War?
It served in the Atlantic, the Mediterranean, and the Pacific, at Casablanca, Sicily, Salerno, Anzio, Normandy, the Solomons, and the Philippines.

What was the main armament?
Fifteen 6-inch/47 guns in five triple turrets, firing eight to ten rounds per minute each, giving a broadside of 120 to 150 rounds per minute.

Which ship was lost in the war?
USS Helena, CL-50, was sunk by three Japanese torpedoes at the Battle of Kula Gulf on 6 July 1943, with the loss of 168 men. She was the only ship of the class lost.

Did the class serve after the war?
Yes. Its ships were sold to Argentina, Brazil, and Chile, where they served into the 1970s and 1980s. The former Phoenix, as the Argentine General Belgrano, was sunk in the Falklands War in 1982.

Sources

• The Naval History and Heritage Command, Brooklyn-class cruiser records
• Norman Friedman, US Cruisers: An Illustrated Design History
• The National WWII Museum, cruiser exhibits
• Robert Gardiner, Conway’s All the World’s Fighting Ships 1922–1946
• The US Navy, Dictionary of American Naval Fighting Ships
• The Imperial War Museum, Mediterranean campaign collection