Independence-Class Aircraft Carrier: America’s Converted Light Carriers

The Independence-class aircraft carriers were nine light carriers of the United States Navy, built during the Second World War by converting the hulls of Cleveland-class light cruisers that were already under construction. The idea was born of urgency: in the summer of 1942, after the loss of four American fleet carriers in the first six months of the Pacific War, the US Navy needed new carriers quickly, and the conversion of cruiser hulls offered a way to produce them faster than building fleet carriers from scratch. The first of the class, USS Independence, was commissioned in January 1943, and the last, USS San Jacinto, in November 1943. The nine ships served throughout the Pacific War, from the Central Pacific offensive to the Battle of Leyte Gulf, where USS Princeton was lost, and they continued in service after the war, in the US Navy and in the navies of France and Spain.

The Independence-class ships were small and fast, displacing about 11,000 tons and capable of 31 knots, with an air group of about 30 aircraft. They were not as capable as the Essex-class fleet carriers, which could carry twice as many aircraft, but they were available when they were needed, and they performed a vital role, providing air cover for amphibious landings, hunting Japanese shipping and supporting the fleet carriers in the great carrier battles of 1944. Their crews called them by many names, and their service was long and hard, from the Gilbert Islands to Okinawa, and from the Philippine Sea to the atomic tests at Bikini Atoll, where USS Independence herself was used as a target ship.

Today the Independence-class is remembered as one of the most successful improvisations in naval history, a class of ships that was built in a hurry, for a desperate need, and that served with distinction. Two of the ships survive in memory through their later service: USS Cabot served with the Spanish Navy as Dedalo until 1989, and USS Monterey became a training carrier. The class’s story is a reminder that, in war, speed of production can matter as much as perfection of design, and that a good ship, available in time, is worth more than a perfect ship that arrives too late.

1. Key Facts

Field	Value
Type	Light aircraft carrier (CVL)
Origin	United States
Builders	New York Shipbuilding Corporation, Camden, New Jersey
Converted from	Cleveland-class light cruiser hulls
Ships in class	9 (Independence, Princeton, Belleau Wood, Cowpens, Monterey, Langley, Cabot, Bataan, San Jacinto)
Commissioned	January–November 1943
Displacement	Approximately 11,000 tons standard; 14,750 tons full load
Length	Approximately 189.70 m (622 ft 6 in)
Beam	Approximately 21.80 m (71 ft 6 in) at waterline; 33.30 m (109 ft 2 in) over flight deck
Draught	Approximately 7.90 m (26 ft)
Propulsion	4 × Babcock and Wilcox boilers; 4 × General Electric steam turbines, 100,000 shp
Speed	31 knots
Range	Approximately 13,000 nautical miles at 15 knots
Complement	Approximately 1,569 officers and men, including air group
Aircraft	Approximately 30–45 (fighters and torpedo bombers)
Armament	2 × 5-inch guns; 16 × 40 mm Bofors; 22 × 20 mm Oerlikon guns
Armour	Belt 3.5–5 inches; deck 2 inches
Losses	1 (USS Princeton, sunk at Leyte Gulf, 24 October 1944)

2. Background and Development

The Carrier Crisis of 1942

In the summer of 1942, the United States Navy faced a crisis in carriers. The battles of the Coral Sea and Midway had cost the Navy four fleet carriers, Lexington, Yorktown, Hornet and Wasp, and the Essex-class fleet carriers that were under construction would not be ready until 1943. The Navy needed carriers urgently, and President Franklin D. Roosevelt, who had a keen interest in naval affairs, suggested converting cruiser hulls into light carriers. The idea was not new: the British had converted cruisers into carriers in the First World War, and the Americans had studied the possibility before the war. In 1942, with nine Cleveland-class cruiser hulls under construction at the New York Shipbuilding Corporation, the Navy decided to convert them, and the Independence-class was born.

The conversion was a major engineering task. The cruiser hulls were long and narrow, with a high speed and a powerful propulsion plant, but they were not designed to carry aircraft. The builders had to add a flight deck, a hangar, lifts, aviation fuel tanks and workshops, and they had to do it quickly. The first ship, Independence, was laid down as a cruiser in May 1941, converted while under construction, and commissioned as a carrier in January 1943, only 17 months after the decision to convert her. The other eight ships followed in rapid succession, and by November 1943 all nine were in service. The speed of the programme was remarkable, and it reflected the urgency of the Navy’s need.

From Cruiser Hull to Carrier

The conversion of a cruiser hull into a carrier involved significant compromises. The hull was narrow, which made the flight deck narrow and the hangar small, and the ships could carry only about 30 aircraft, compared with the 90 or more carried by an Essex-class carrier. The ships were also top-heavy, with a high centre of gravity, and they rolled badly in heavy seas, a quality that made flying operations difficult. The cruiser’s machinery, however, was a strength: the four boilers and turbines gave the ships a speed of 31 knots, fast enough to keep up with the fleet carriers, and their range was good. The Independence-class ships were not ideal carriers, but they were fast, available and capable, and they filled a gap that no other ships could fill.

The class was named for the first ship, USS Independence, which was herself named for the American ideal of independence. The other ships were named for famous battles and for earlier carriers: Princeton, for the Revolutionary War battle; Belleau Wood, for the Marine Corps battle in France; Cowpens, for the Revolutionary War battle; Monterey, for the Mexican War battle; Langley, for the Navy’s first carrier; Cabot, for the explorer; Bataan, for the Philippine peninsula; and San Jacinto, for the Texas battle. The names reflected the Navy’s traditions and the ships’ place in American naval history.

The Decision to Convert

The decision to convert the cruiser hulls was controversial. Some officers argued that the cruisers were needed as cruisers, and that the converted carriers would be too small and too vulnerable to be useful. Others argued that the Navy needed carriers more than it needed cruisers, and that the conversion was the fastest way to obtain them. Roosevelt’s support for the conversion was decisive, and the programme went ahead. The decision was vindicated by the ships’ service: the Independence-class carriers fought in every major Pacific operation from 1943 onwards, and they proved their worth time and again. The conversion was one of the most successful improvisations of the war.

3. Design

Hull, Flight Deck and Hangar

The Independence-class ships were built on Cleveland-class cruiser hulls, about 190 metres long and 22 metres wide at the waterline. The flight deck was about 170 metres long and 33 metres wide, with two lifts, one forward and one aft, and a small island on the starboard side. The hangar, below the flight deck, was about 100 metres long and could hold about 20 aircraft, with the remainder parked on the flight deck. The ships’ narrow beam made the flight deck narrow, and the hangar was cramped, but the design was workable, and the ships could operate a useful air group. The flight deck was fitted with arrester wires and a catapult, and the ships could launch and recover aircraft in most weather conditions, although their rolling in heavy seas made flying difficult.

The ships’ appearance was distinctive: a long, narrow hull, a small island and a flight deck that overhung the hull on both sides. The ships were often mistaken for fleet carriers at a distance, but their small size was apparent up close. The design’s main weakness was its stability: the ships were top-heavy, with a high centre of gravity, and they rolled heavily in a seaway. The crews learned to live with the rolling, but it was a constant problem, and it limited the ships’ effectiveness in bad weather. The ships were also vulnerable to damage, with thin armour and a small size that made them easy targets for kamikazes.

Propulsion and Speed

The Independence-class ships retained the Cleveland-class cruisers’ propulsion plant: four Babcock and Wilcox boilers and four General Electric steam turbines, producing 100,000 shaft horsepower and driving four screws. The plant gave the ships a speed of 31 knots, fast enough to operate with the fleet carriers, and a range of about 13,000 nautical miles at 15 knots. The machinery was reliable and well proven, and it was one of the class’s strengths. The ships’ speed was essential to their role: they needed to keep up with the fast carrier task forces, and they needed to generate enough wind over the deck to launch and recover aircraft. The 31-knot speed was a significant advantage over the slower escort carriers, which could make only 18 knots.

Aircraft, Armament and Protection

The Independence-class air group consisted of about 30 aircraft, typically a fighter squadron of about 20 Hellcats and a torpedo squadron of about 10 Avengers, although the composition varied during the war. The air group was small, but it was effective, and the ships’ aircraft flew combat air patrols, anti-submarine patrols and strike missions. The ships’ armament consisted of two 5-inch guns, 16 40 mm Bofors guns and 22 20 mm Oerlikon guns, a heavy anti-aircraft battery for a ship of their size. The armour was light, with a belt of 3.5 to 5 inches and a deck of 2 inches, reflecting the ships’ cruiser origins. The light armour made the ships vulnerable to bombs and torpedoes, and Princeton’s loss at Leyte Gulf showed the danger: a single bomb hit started a fire that could not be controlled, and the ship was lost.

4. Variants

The Nine Ships

The nine Independence-class ships were built to a common design, but they differed in detail, reflecting the lessons learned from the earlier ships. Independence, the first ship, was commissioned in January 1943 and served as a night carrier, operating night fighters in the Pacific. Princeton, the second ship, was commissioned in February 1943 and was lost at Leyte Gulf in October 1944. Belleau Wood, Cowpens, Monterey, Langley, Cabot, Bataan and San Jacinto were commissioned between March and November 1943, and they served throughout the Pacific War. Each ship had its own history, and each earned battle stars for its service, but they shared a common design and a common role.

Post-War Service and Transfers

After the war, the Independence-class ships were decommissioned, but several returned to service in the 1950s as training carriers and as anti-submarine carriers. Monterey served as a training carrier until 1956, and Bataan served as an anti-submarine carrier until 1954. Cabot was transferred to Spain in 1967, where she served as Dedalo until 1989, the last of the class in service. Belleau Wood was transferred to France in 1953, where she served as Bois Belleau until 1960. The class’s post-war service was long, and the ships’ versatility, as training carriers, as anti-submarine carriers and as foreign transfers, reflected the soundness of their design.

5. Operational History

The Central Pacific Offensive

The Independence-class ships entered combat in the autumn of 1943, when they joined the fast carrier task forces for the offensive in the Central Pacific. They fought in the Gilbert Islands campaign, providing air cover for the landings on Tarawa and Makin, and in the Marshall Islands campaign, where they supported the landings on Kwajalein and Eniwetok. The ships’ aircraft flew combat air patrols, bombed Japanese positions and attacked shipping, and their crews learned the business of carrier warfare in the hard school of combat. The Independence-class ships were not the fleet’s main striking power, but they were an essential part of it, and their contribution to the Central Pacific offensive was significant.

The Philippine Sea and Leyte Gulf

In June 1944, the Independence-class ships fought in the Battle of the Philippine Sea, the great carrier battle in which the Japanese naval air arm was destroyed. The ships’ fighters flew combat air patrols, shooting down Japanese aircraft, and their torpedo bombers attacked Japanese ships. In October 1944, the ships fought in the Battle of Leyte Gulf, the largest naval battle in history, where they supported the landings on Leyte and fought off Japanese air attacks. It was at Leyte Gulf, on 24 October 1944, that USS Princeton was hit by a bomb from a Japanese dive bomber. The bomb started a fire that spread to the ship’s magazines, and despite the efforts of her crew and of the ships that came to her aid, Princeton was lost, with the deaths of 108 of her crew. The loss was a reminder of the vulnerability of the light carriers, and of the dangers of the kamikaze era that was just beginning.

Okinawa, the End of the War and Bikini

In 1945, the Independence-class ships fought in the campaign for Okinawa, where they faced the full fury of the kamikaze attacks. The ships’ anti-aircraft guns shot down many kamikazes, but several ships were damaged, and the crews endured weeks of constant alerts. After the war, the ships took part in the occupation of Japan and in Operation Magic Carpet, bringing American servicemen home. USS Independence herself was used as a target ship in Operation Crossroads, the atomic bomb tests at Bikini Atoll in 1946, where she survived two atomic explosions, although she was heavily contaminated and was later sunk as a target. The class’s war ended as it had begun, in the service of the Navy’s most urgent needs.

USS Princeton at Leyte Gulf

The loss of USS Princeton at Leyte Gulf deserves to be told in detail. On the morning of 24 October 1944, Princeton was operating east of Luzon when she was attacked by a Japanese Yokosuka D4Y Judy dive bomber, which dropped a bomb that penetrated the flight deck and exploded in the hangar, starting a fire. The fire spread, and despite the efforts of the crew and of the cruiser Birmingham, which came alongside to fight the fire, the ship’s magazines exploded, killing 229 men aboard Birmingham and 108 aboard Princeton. Princeton was abandoned and sunk by torpedoes from American destroyers. The loss was a tragedy, but it also demonstrated the courage of the men who fought the fire, and the risks that the light carriers faced.

6. Performance and Specifications

Strengths in Combat

The Independence-class ships’ strengths were their speed, their availability and their versatility. At 31 knots, they could operate with the fast carrier task forces, and their air groups, although small, were effective. The ships were available when they were needed, in 1943, when the Navy had few carriers, and they filled a gap that no other ships could fill. Their versatility was also a strength: they served as fleet carriers, as night carriers, as training carriers and as anti-submarine carriers, and they performed each role well. The class’s speed of construction, 17 months from decision to commissioning for the first ship, was itself a strength, and it reflected the urgency of the Navy’s need.

Weaknesses and Limitations

The class’s weaknesses were its small air group, its narrow flight deck and its poor stability. With only about 30 aircraft, the ships could not deliver the striking power of a fleet carrier, and their narrow flight deck made flying operations difficult. Their rolling in heavy seas limited their effectiveness in bad weather, and their light armour made them vulnerable to bombs and torpedoes. The loss of Princeton showed that a single bomb hit could destroy a light carrier, and the ships’ vulnerability was a constant concern. The Independence-class ships were a compromise, and their weaknesses reflected the compromises of their design.

7. Comparison

The Independence-Class and the Essex-Class

The Independence-class is inevitably compared with the Essex-class fleet carriers, and the comparison shows the trade-offs of the conversion. The Essex-class ships displaced about 27,000 tons, carried 90 aircraft and were the main striking power of the Pacific Fleet. The Independence-class ships displaced about 11,000 tons, carried 30 aircraft and were auxiliaries to the fleet carriers. The Essex-class ships were better in every respect except speed of construction: they took longer to build, and they were not available in 1943, when the Navy needed carriers most. The Independence-class ships were available, and they filled the gap until the Essex-class ships arrived in numbers. The two classes complemented each other, and the Navy needed both.

The Independence-Class and the Escort Carriers

The Independence-class ships were also compared with the escort carriers, the small, slow carriers built on merchant hulls that protected convoys and supported amphibious landings. The escort carriers were slower, at 18 knots, and carried about 28 aircraft, but they were cheaper and more numerous. The Independence-class ships were faster and more capable, and they could operate with the fleet, while the escort carriers could not. The two types served different roles, and both were essential to the Navy’s victory in the Pacific. The Independence-class ships were the fleet’s light carriers, and the escort carriers were the fleet’s workhorses, and together they gave the Navy the air power it needed.

8. Legacy

An Improvisation That Worked

The Independence-class’s legacy is that of a successful improvisation. The decision to convert cruiser hulls into carriers was controversial, but it was vindicated by the ships’ service, and it demonstrated that, in war, speed of production can matter as much as perfection of design. The class’s ships served in every major Pacific operation, and they earned a total of 60 battle stars between them. The class’s story is a reminder that naval history is not only the story of great ships, but also the story of the men who built them and sailed them, and of the decisions that were made in haste and under pressure.

The Class in Memory

The Independence-class is remembered in the histories of the Pacific War and in the memories of the men who served aboard the ships. USS Cabot, which served with the Spanish Navy as Dedalo until 1989, was the last of the class in service, and her long career is a testament to the soundness of the design. The class’s ships are also remembered through their air groups, whose pilots flew from their narrow decks in the most demanding conditions, and through the loss of Princeton, whose crew is commemorated at the Leyte Gulf memorials. The Independence-class’s legacy is secure, as one of the most successful classes of carriers in naval history.

9. Surviving Examples

No Surviving Independence-Class Carrier

No Independence-class carrier survives. The last of the class, Cabot, which served with the Spanish Navy as Dedalo, was decommissioned in 1989 and was scrapped in 2002, despite efforts to preserve her as a museum ship in the United States. The other ships were scrapped in the 1950s, 1960s and 1970s, after long service in the US Navy and in foreign navies. The absence of a surviving ship makes the class’s history all the more important, since it is preserved in photographs, in films and in the memories of the men who served aboard the ships.

Models, Photographs and Records

The Independence-class ships are preserved in the records of the US Navy, in the photographs taken by their crews and in the models held by museums, including the National Museum of the US Navy in Washington, D.C., and the Naval History and Heritage Command. The ships’ war diaries, action reports and aircraft logs are held by the National Archives, and they provide a detailed record of the class’s service. The loss of Princeton is commemorated at the Manila American Cemetery, where the names of her dead are recorded, and at the Leyte Gulf memorials. The class’s story continues to be told in books and documentaries about the Pacific War.

10. Frequently Asked Questions

How many Independence-class carriers were built?
Nine Independence-class light carriers were built, all converted from Cleveland-class light cruiser hulls. They were commissioned between January and November 1943.

Why were cruisers converted into carriers?
In the summer of 1942, after the loss of four American fleet carriers, the US Navy needed new carriers urgently. Converting cruiser hulls that were already under construction was faster than building fleet carriers from scratch, and the first ship was commissioned only 17 months after the decision was made.

How many aircraft did an Independence-class carrier carry?
An Independence-class carrier typically carried about 30 aircraft, usually a fighter squadron of about 20 Hellcats and a torpedo squadron of about 10 Avengers, although the composition varied during the war.

Which Independence-class carrier was sunk?
USS Princeton was sunk at the Battle of Leyte Gulf on 24 October 1944, after being hit by a bomb from a Japanese dive bomber. The bomb started a fire that spread to the ship’s magazines, and 108 of her crew were killed.

What happened to USS Independence after the war?
USS Independence was used as a target ship in Operation Crossroads, the atomic bomb tests at Bikini Atoll in 1946. She survived two atomic explosions, but was heavily contaminated and was later sunk as a target ship.

Are any Independence-class carriers still in existence?
No. The last of the class, USS Cabot, served with the Spanish Navy as Dedalo until 1989 and was scrapped in 2002, despite efforts to preserve her as a museum ship.

11. Sources

• Norman Friedman, U.S. Aircraft Carriers: An Illustrated Design History (Naval Institute Press).
• The Naval History and Heritage Command, Independence-class carrier records and war diaries.
• Samuel Eliot Morison, History of United States Naval Operations in World War II, volumes on the Pacific War.
• The National Museum of the US Navy, Washington, D.C., carrier collection records.
• Robert C. Stern, The Lexington, Saratoga and Enterprise (Naval Institute Press).
• Wikipedia, Independence-class aircraft carrier.