Allen M. Sumner-class destroyer

The Allen M. Sumner-class destroyer was an American destroyer class of the Second World War, an improved version of the Fletcher class with six 5-inch guns in three twin turrets, a heavier torpedo armament, and a stronger anti-aircraft battery. Fifty-eight ships were built between 1943 and 1945, and they served in the Pacific, where they screened carriers, bombarded Japanese-held islands, and fought in the battles of Leyte Gulf, Iwo Jima, and Okinawa. The class remained in service after the war, fighting in Korea and Vietnam, and serving with the navies of many other countries into the 1980s and 1990s. The Allen M. Sumner class was one of the most successful destroyer designs of the Second World War.

1. Key Facts

Field	Value
Type	Destroyer
Country	United States
Designer	Gibbs and Cox (Fletcher development)
Production	1943–1945
Number built	58
Displacement	2,200 tons standard; about 3,218 tons full load
Length	114.8 metres (376 ft 6 in)
Beam	12.5 metres (41 ft)
Draught	4.8 metres (15 ft 9 in)
Propulsion	Steam turbines, 60,000 shaft horsepower, 2 shafts
Speed	34 knots
Range	About 6,500 nautical miles at 15 knots
Complement	336 officers and men
Main armament	6 × 5-inch (127 mm) guns in 3 twin turrets
Anti-aircraft armament	12 × 40 mm Bofors; 11 × 20 mm Oerlikon
Torpedo tubes	10 × 21-inch (533 mm) in 2 quintuple mounts
Anti-submarine weapons	Depth charges, Hedgehog (later)
Main theatres	Pacific 1944–1945; Korea 1950–1953; Vietnam 1960s
Named for	Allen Melancthon Sumner, US Marine Corps officer killed in 1918

2. Origins and Development

Improving the Fletcher Class

The Allen M. Sumner class was developed from the Fletcher class, the standard American destroyer of the Second World War, which had five 5-inch guns in single mounts and ten torpedo tubes. The Fletcher was a successful design, but the United States Navy wanted a destroyer with a heavier gun armament, a stronger anti-aircraft battery, and a more efficient layout, and the Sumner class was the answer. The new class kept the hull and the machinery of the Fletcher, but it carried six 5-inch guns in three twin turrets, two forward and one aft, which gave it a heavier broadside and a better rate of fire. The twin turrets were faster to train and to elevate than the single mounts, and they allowed the ship to engage aircraft and surface targets more effectively.

The Twin 5-inch Turret

The twin 5-inch turret was the most important innovation of the Sumner class, because it doubled the number of guns in the forward turrets and gave the ship a powerful anti-aircraft and anti-surface armament. The 5-inch/38 gun was the standard American destroyer gun, a dual-purpose weapon that could fire at aircraft and at surface targets, with a rate of fire of about fifteen rounds per minute per gun. The twin turret was heavier than the single mount, and it required a stronger hull and a larger crew, but it was worth the cost, because it made the Sumner class the most heavily armed destroyer in the American Navy. The twin turret was also used in the later Gearing class, and it became the standard destroyer armament for the next generation of American destroyers.

Construction Programme

Fifty-eight Allen M. Sumner-class destroyers were built between 1943 and 1945, by six shipyards, including Bath Iron Works in Maine, the Federal Shipbuilding Company in New Jersey, and the Bethlehem Steel Company in California. The first ship, USS Allen M. Sumner, was launched in December 1943 and commissioned in January 1944, and the last ships were completed in 1945, too late to see combat in the Second World War. The class was built quickly, because the United States needed destroyers to escort carriers and convoys in the Pacific, and the shipyards were able to build a Sumner in about a year, using mass-production methods that had been perfected on the Fletcher class. The Sumner class was one of the largest destroyer programmes of the war, and it showed the industrial power of the United States.

The Gearing Connection

The Allen M. Sumner class was closely related to the Gearing class, which was a lengthened version of the Sumner with more fuel capacity and a longer range. The Gearing class was built after the Sumner class, and it became the standard American destroyer of the post-war period, while the Sumner class was gradually retired. The two classes were so similar that they were often grouped together, and they shared the same guns, the same machinery, and the same layout, with the Gearing being fourteen feet longer. The Sumner class was the bridge between the Fletcher and the Gearing, and it showed how a successful design could be improved and adapted for new roles.

3. Technical Design

Hull, Machinery, and Speed

The Allen M. Sumner class was 114.8 metres long, 12.5 metres wide, and displaced 2,200 tons standard and about 3,218 tons at full load. Her steam turbines produced 60,000 shaft horsepower, driving two shafts, and gave her a top speed of 34 knots, which made her one of the fastest destroyers of the war. Her range was about 6,500 nautical miles at 15 knots, which was enough for operations in the Pacific, though it was less than that of the Gearing class, which had more fuel. Her hull was strong and well built, and it could survive damage that would have sunk a smaller ship, as the class proved at Okinawa, where several ships were hit by kamikaze aircraft and survived. Her machinery was reliable, and her crew of 336 officers and men was well trained and experienced.

Main Battery and Fire Control

The main battery of the Sumner class was six 5-inch/38 guns in three twin turrets, two forward and one aft, controlled by a Mk 37 fire-control system with a Mk 12 radar, which allowed the ship to engage aircraft and surface targets at long range and in bad weather. The 5-inch gun could fire a 25-kilogram shell to a range of about 16 kilometres, and it could fire fifteen rounds per minute, which gave the Sumner class a powerful broadside. The fire-control system was one of the best in the world, and it allowed the Sumner class to shoot down Japanese aircraft and to bombard Japanese-held islands with great accuracy. The main battery was the heart of the ship, and it was the reason why the Sumner class was so effective in the Pacific.

Anti-Aircraft and Torpedo Armament

The anti-aircraft armament of the Sumner class was twelve 40-millimetre Bofors guns in twin and quad mounts, and eleven 20-millimetre Oerlikon cannon, which gave her a strong defence against Japanese aircraft, including the kamikaze. The Bofors gun was the best light anti-aircraft gun of the war, with a rate of fire of about 120 rounds per minute, and it was used by every Allied navy. The torpedo armament was ten 21-inch torpedo tubes in two quintuple mounts, which gave the Sumner class a powerful torpedo broadside, though in practice the torpedoes were rarely used in the Pacific, because the Japanese Navy had been destroyed by 1944. The anti-submarine armament included depth charges and, later, the Hedgehog mortar, which allowed the Sumner class to hunt submarines as well as to fight aircraft and surface ships.

4. Service in the Pacific

Leyte Gulf and the Philippines

The Allen M. Sumner class first saw combat in the Philippines in 1944, where its ships screened the carriers and the invasion fleet, bombarded Japanese positions, and fought in the Battle of Leyte Gulf, the largest naval battle in history. The destroyers of the class were part of the escort for the invasion of Leyte, and they fought off Japanese aircraft and submarines, and they bombarded the beaches before the landings. At Leyte Gulf, the Sumner-class destroyers were among the ships that screened the American carriers, and they helped to sink Japanese ships and to shoot down Japanese aircraft. The class performed well in its first combat, and it established a reputation for reliability and for fighting spirit.

Iwo Jima and Okinawa

At Iwo Jima in February 1945, the Sumner-class destroyers bombarded the island before the landings, providing fire support for the Marines, and they screened the carriers against Japanese air attack. At Okinawa in April 1945, the class was in the thick of the fighting, serving on the radar picket line, where destroyers were stationed to warn the fleet of incoming Japanese aircraft, and where they were attacked by kamikaze pilots. Several Sumner-class destroyers were hit by kamikaze aircraft at Okinawa, including USS Laffey, which was hit by six kamikaze and four bombs on 16 April 1945 and survived, a feat that earned her the nickname “The Ship That Would Not Die”. The Okinawa campaign was the hardest test of the class, and it showed that the Sumner destroyers were tough, well built, and well fought.

The Radar Picket Line

The radar picket line at Okinawa was one of the most dangerous duties of the war, because the destroyers on the line were the first ships to be attacked by Japanese kamikaze aircraft, and they had to warn the fleet and shoot down as many attackers as they could. The Sumner-class destroyers on the picket line shot down many Japanese aircraft, but they also suffered heavy losses, with several ships sunk or badly damaged. The experience of the picket line showed that the destroyer, with its radar and its anti-aircraft guns, was essential to the defence of the fleet, and that it could survive damage that would have sunk a smaller ship. The Sumner class earned a reputation for toughness at Okinawa, and its ships were decorated for their service.

5. Service in Korea and Vietnam

The Korean War

After the Second World War, the Allen M. Sumner class remained in service with the United States Navy, and it fought in the Korean War from 1950 to 1953, where its ships bombarded North Korean positions, screened carriers, and patrolled the coast. The class was well suited to the Korean War, because its 5-inch guns were effective against shore targets, and its speed and its anti-aircraft armament made it useful for escorting carriers. The Sumner-class destroyers served in Korea for the whole of the war, and they earned battle stars for their service. After Korea, the class was modernised under the FRAM programme, which improved its anti-submarine weapons and its electronics, and it continued to serve into the 1960s and 1970s.

Vietnam and the Cold War

In the 1960s, the Sumner class served in Vietnam, where its ships bombarded Viet Cong positions, patrolled the coast, and provided fire support for American and South Vietnamese troops. The class was also used for anti-submarine patrols in the Atlantic and the Pacific, and for showing the flag in the Mediterranean and the Far East. The Sumner-class destroyers were gradually retired in the 1970s, as newer destroyers entered service, but they remained in service with the navies of other countries, including Argentina, Brazil, Chile, Colombia, Greece, Iran, South Korea, Taiwan, Turkey, and Venezuela, where they served into the 1980s and 1990s. The class was one of the longest-serving destroyer designs of the Second World War.

6. Strengths

Firepower and Versatility

The greatest strength of the Allen M. Sumner class was its firepower, because six 5-inch guns in twin turrets gave it a heavier broadside than any other American destroyer of the war, and its anti-aircraft battery of Bofors and Oerlikon guns gave it a strong defence against aircraft. The class was also versatile, because it could screen carriers, bombard shore targets, hunt submarines, and fight surface ships, and it did all of these jobs well. Its speed of 34 knots made it fast enough to operate with the fleet, and its range was enough for operations in the Pacific. The Sumner class was a destroyer that could do everything, and it was trusted by the admirals who commanded it.

Toughness and Survivability

The Sumner class was tough and survivable, because it was well built, with a strong hull and a good damage-control system, and because its crew was well trained and experienced. The class proved its toughness at Okinawa, where USS Laffey survived six kamikaze hits and four bombs, and where other ships survived damage that would have sunk a smaller vessel. The Sumner-class destroyers were also well designed, with a good layout and a comfortable crew accommodation, which made them popular with their crews. Their toughness and their survivability were the reasons why they remained in service for so long, and why they were sold to so many other navies after the war.

7. Weaknesses

Range and Habitability

The main weakness of the Allen M. Sumner class was its range, which was about 6,500 nautical miles at 15 knots, less than that of the Gearing class, which had more fuel and a longer range. The Sumner class was designed for operations in the Pacific, but its range was limited, and it needed frequent refuelling, which was a disadvantage on long patrols. The class was also cramped, because it carried a crew of 336 men in a hull that was only 114.8 metres long, and its habitability was poor by modern standards, with crowded mess decks and limited fresh water. These were minor weaknesses compared with its strengths, but they were real, and they were among the reasons why the Gearing class, with its longer hull and its greater fuel capacity, became the standard post-war destroyer.

Anti-Submarine Limitations

The Sumner class was designed as a gun destroyer, not as an anti-submarine destroyer, and its anti-submarine weapons were limited, consisting mainly of depth charges and, later, the Hedgehog mortar. It was not as effective as the later destroyer escorts and frigates in hunting submarines, and it was gradually replaced in that role by specialised anti-submarine ships. The class was also vulnerable to kamikaze attack, because its anti-aircraft guns, though powerful, could not stop every attacker, and several ships were sunk or badly damaged at Okinawa. These were weaknesses of the design, but they were shared by every destroyer of the period, and they did not prevent the Sumner class from being one of the most successful destroyer designs of the war.

8. Notable Ships

USS Laffey

USS Laffey, DD-724, was the most famous ship of the Allen M. Sumner class, because she survived one of the most intense kamikaze attacks of the war at Okinawa on 16 April 1945. She was hit by six kamikaze aircraft and four bombs, which killed 32 of her crew and wounded 71, but she remained afloat and was towed to safety, earning the nickname “The Ship That Would Not Die”. Laffey was repaired and returned to service, fighting in Korea and Vietnam, and she is now preserved as a museum ship at Patriots Point in Charleston, South Carolina, where she is open to visitors. Laffey is a symbol of the toughness and the fighting spirit of the Sumner class, and she is one of the most visited museum ships in the United States.

USS Allen M. Sumner and Others

USS Allen M. Sumner, DD-692, was the lead ship of the class, commissioned in January 1944, and she served in the Pacific, in Korea, and in Vietnam, before being sold to the Brazilian Navy in 1974. Other notable ships of the class included USS Moale, which served at Leyte Gulf, USS Ingraham, which served in the Mediterranean and the Pacific, and USS Meredith, which was sunk by a mine in the English Channel in June 1944, one of the few ships of the class lost in the Second World War. The class served with distinction in every theatre, and its ships earned many battle stars and decorations. The Sumner class was a class of which the United States Navy was proud, and its ships are remembered for their service in three wars.

9. Legacy

Long Service and Foreign Navies

The legacy of the Allen M. Sumner class is its long service, because it served in the Second World War, in Korea, and in Vietnam, and with the navies of many other countries into the 1980s and 1990s. The class was sold to Argentina, Brazil, Chile, Colombia, Greece, Iran, South Korea, Taiwan, Turkey, and Venezuela, where it served as the backbone of their navies, and where some ships remained in service into the twenty-first century. 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 destroyer design could remain useful for decades.

Influence on Destroyer Design

The Allen M. Sumner class influenced the design of later American destroyers, notably the Gearing class, which was a lengthened Sumner, and the Forrest Sherman class, which used the twin 5-inch turret pioneered by the Sumner. The twin 5-inch turret became the standard American destroyer armament for the next generation, and the Sumner class showed that a destroyer could be a versatile, multi-role ship, capable of screening carriers, bombarding shore targets, and hunting submarines. The class is remembered as one of the best destroyer designs of the Second World War, and as a ship that served its country in three wars and many navies around the world.

Frequently Asked Questions

What is the Allen M. Sumner-class destroyer?
It is an American destroyer class of the Second World War, an improved Fletcher with six 5-inch guns in three twin turrets, a heavier anti-aircraft battery, and ten torpedo tubes.

How many Sumner-class destroyers were built?
Fifty-eight were built between 1943 and 1945, by six shipyards in the United States.

What was the main armament?
Six 5-inch/38 guns in three twin turrets, controlled by a Mk 37 fire-control system, plus twelve 40-millimetre Bofors and eleven 20-millimetre Oerlikon anti-aircraft guns.

Where did the class serve in the Second World War?
It served in the Pacific, at Leyte Gulf, Iwo Jima, and Okinawa, where its ships screened carriers, bombarded islands, and served on the radar picket line.

What is USS Laffey?
USS Laffey, DD-724, is the most famous ship of the class. She survived six kamikaze hits and four bombs at Okinawa on 16 April 1945 and is now a museum ship at Patriots Point, South Carolina.

Did the class serve after the war?
Yes. It served in Korea and Vietnam, and with the navies of many other countries into the 1980s and 1990s.

Sources

• The Naval History and Heritage Command, Allen M. Sumner-class destroyer records
• Norman Friedman, US Destroyers: An Illustrated Design History
• The National WWII Museum, destroyer exhibits
• The Patriots Point Naval and Maritime Museum, USS Laffey collection
• Robert Gardiner, Conway’s All the World’s Fighting Ships 1922–1946
• The US Navy, Dictionary of American Naval Fighting Ships