During World War II, naval warfare evolved rapidly, requiring ships to be armed with versatile and powerful weaponry to counter multiple threats. Destroyer escorts like the USS Stewart (DE-238) played a crucial role in convoy protection, anti-aircraft defense, and anti-submarine warfare, making them indispensable to the Allied naval strategy. Equipped with a mix of dual-purpose guns, automatic anti-aircraft cannons, and specialized anti-submarine weapons, the USS Stewart was designed to handle a variety of combat scenarios.
This article explores the primary armaments of the USS Stewart, including the 3-inch/50-caliber dual-purpose guns, Bofors 40mm anti-aircraft cannons, Oerlikon 20mm rapid-fire guns, depth charge projectors, and Hedgehog anti-submarine weapons. These weapons made the USS Stewart a formidable opponent against enemy aircraft, surface ships, and submarines.
3-inch/50-Caliber Dual-Purpose Guns: The Backbone of the USS Stewart’s Firepower
The 3-inch/50-caliber dual-purpose gun was the primary weapon system aboard the USS Stewart. Designed to engage both surface and aerial threats, this quick-firing artillery piece provided a crucial balance between firepower and versatility.
Specifications and Performance
The 3-inch/50-caliber gun had a barrel length of 50 calibers (approximately 150 inches) and was capable of firing a variety of fixed ammunition rounds. Each round weighed 34 pounds, consisting of a powder case and projectile permanently attached for rapid loading.
The shells themselves weighed about 13 pounds and came in two primary types:
Anti-Aircraft (AA) Rounds: Contained an explosive bursting charge of 0.81 pounds.
High-Capacity (HC) Rounds: Featured a 1.27-pound explosive charge for greater impact against surface targets.
The gun had an impressive maximum range of 14,600 yards (8.3 miles) at a 45-degree elevation and could reach a ceiling of 29,800 feet (5.6 miles) at an 85-degree elevation, making it effective against high-altitude aircraft. Its barrel had a life expectancy of 4,300 effective full charges, ensuring long-term reliability in combat.
The 3-inch/50-Caliber Gun vs. Kamikaze Attacks
By the final year of World War II, the U.S. Navy faced an increasing threat from Japanese kamikaze aircraft—suicidal pilots who would crash explosive-laden planes into Allied ships. During these attacks, smaller-caliber weapons like the Oerlikon 20mm and Bofors 40mm guns often lacked the stopping power to destroy kamikazes before they reached their targets.
As a result, the 3-inch/50-caliber gun became a more valuable asset, providing the necessary firepower and range to take down incoming aircraft before they could complete their deadly missions. Its ability to fire high-capacity explosive rounds made it a more effective defense against heavily armored enemy planes, solidifying its place as a key component of naval anti-aircraft strategy.
Bofors 40mm L/60: The Versatile Anti-Aircraft Gun
The Bofors 40mm L/60 was one of the most successful and widely used medium anti-aircraft guns of World War II. Developed by the Swedish arms manufacturer AB Bofors in the 1930s, it was adopted by nearly all Western Allied nations and even some Axis powers like Nazi Germany and Hungary.
Why the Bofars 40mm Was So Effective
The Bofors 40mm L/60 filled a crucial role in naval anti-aircraft defense. It was an intermediate weapon, bridging the gap between the high rate of fire of smaller-caliber guns (like the Oerlikon 20mm) and the long-range power of heavy artillery (like the 5-inch guns on larger warships).
The Bofors 40mm was highly regarded for its speed, precision, and reliability, making it a staple aboard destroyers, cruisers, and even battleships. Its effectiveness was far superior to competing designs from the years leading up to WWII, ensuring its place as a primary anti-aircraft weapon for the majority of the war.
Post-War Limitations
While the Bofors 40mm L/60 was excellent against propeller-driven aircraft, it struggled against faster, jet-powered aircraft in the post-war era. This led to the development of the Bofors 40mm L/70, a more powerful version designed to counter the new aviation threats of the Cold War.
Oerlikon 20mm: The Rapid-Fire Workhorse
The Oerlikon 20mm cannon was one of the most widely used naval weapons of World War II. Installed on virtually every U.S. Navy warship, from PT boats to aircraft carriers, it played a key role in the defense against enemy aircraft and small surface threats.
Advantages to the Oerlikon 20mm
High rate of fire: Capable of firing 450 rounds per minute.
Quick response: Could be brought into action almost instantly.
No external power required: The gun was self-contained and did not require an external cooling or power supply.
Easy installation: The weapon could be bolted onto any available deck space, making it a flexible and adaptable option for naval defense.
The Oerlikon fired a 0.3-pound explosive shell from a 60-round detachable magazine. A gunner could expend all 60 rounds in just 7.5 seconds, making it a fast and effective weapon for close-range engagements.
Combat Performance
Between December 1941 and September 1944, Oerlikon 20mm guns were responsible for 32% of all Japanese aircraft downed by the U.S. Navy. Its effectiveness against enemy aircraft made it an essential part of any warship’s arsenal.
However, as aircraft speeds increased, the Oerlikon’s limited range and stopping power led to its replacement by larger-caliber weapons like the 3-inch/50-caliber gun in later stages of the war.
Anti-Submarine Warfare: Depth Charges and Hedgehogs
The USS Stewart was also well-equipped to combat enemy submarines, using a combination of depth charges and Hedgehog weapons to hunt and destroy underwater threats.
Depth Charges and K-Guns
Depth charges were explosive devices designed to detonate at a specific depth, forcing enemy submarines to surface or be destroyed by the shockwave.
Depth charge tracks allowed charges to be rolled off the stern of the ship.
K-guns (projectors) launched 300-pound depth charges off the sides of the vessel, expanding the attack area.
Hedgehog Weapons: A More Precise Solution
Unlike traditional depth charges, Hedgehog mortars fired a spread of 24 projectiles, each weighing 65 pounds with an explosive charge of 35 pounds.
The biggest advantage of Hedgehogs was that they only detonated on contact with a submarine. This meant that unsuccessful attacks did not create disruptive underwater explosions, allowing sonar operators to immediately resume tracking enemy submarines instead of waiting for turbulence to settle.
Additionally, Hedgehogs had a higher sink rate than traditional depth charges, increasing the chances of hitting fast-moving submarines.
AÂ Powerful Guardian of the Sea
The USS Stewart’s diverse arsenal of anti-aircraft, surface, and anti-submarine weaponry made it a formidable warship during World War II. Whether defending against kamikaze attacks, engaging enemy aircraft, or hunting submarines, the USS Stewart was a key protector of Allied fleets.
Its combination of 3-inch/50-caliber guns, Bofors 40mm cannons, Oerlikon 20mm guns, depth charges, and Hedgehog mortars reflected the evolving needs of naval warfare, ensuring it remained an essential asset in the fight for victory at sea.
USS Stewart (DE-238) at Home in Galveston, Texas
The USS Stewart (DE-238) is one of only two preserved Destroyer Escorts in the United States. Its home is Seawolf Park, home of the Galveston Naval Museum. Climb aboard the USS Stewart at the Galveston Naval Museum, and experience an important part of naval history in Texas.  Â