The 5″/25 Battery Aboard the USS New Mexico During the Bombardment of Saipan: June 15, 1944

In the summer of 1944, the Pacific Theater of World War II was at its peak, with Allied forces advancing through the Mariana Islands as part of the strategy to weaken Japan’s hold on the Pacific. One of the key engagements in this campaign was the Battle of Saipan, which would not only mark a turning point in the war but also showcase the pivotal role of U.S. Navy battleships in providing fire support for ground troops. Among the ships involved in the bombardment of Saipan was the USS New Mexico (BB-40), a South Dakota-class battleship that had been in service since the early years of the war. The ship’s 5″/25-caliber gun battery played a significant role during the operation, providing crucial fire support for the landing forces.

Background on the USS New Mexico and its Role in World War II

Commissioned in 1918, the USS New Mexico was one of the United States Navy’s early 35,000-ton battleships, designed for fleet actions and naval dominance in the event of war. By the time World War II erupted, the New Mexico had undergone numerous modernizations, including the upgrading of its armament to enhance its effectiveness in battle. It was primarily equipped with eight 14-inch guns as its main battery, but it also boasted several smaller caliber secondary batteries, including the 5″/25-caliber guns, which were used for anti-aircraft defense and surface fire support during operations.

The USS New Mexico had already seen action in the early years of World War II, participating in the Battle of Guadalcanal and other Pacific engagements. However, by 1944, the ship’s most significant and sustained contributions came from its role in the invasions of the Pacific Islands, where it supported amphibious landings and provided devastating bombardment of enemy positions.

The Saipan Campaign

The Battle of Saipan was one of the most critical operations in the Pacific during 1944. Saipan, an island in the Northern Mariana Islands, was strategically important due to its proximity to Japan’s home islands and its ability to serve as a base for American bombers. Capturing Saipan would not only deprive Japan of a valuable military base but also provide the United States with a platform for launching further strikes against Japan’s heartland.

The U.S. Navy’s role in the invasion of Saipan was crucial, as battleships and other naval vessels provided fire support to the Marines and Army soldiers who were landing on the island. These naval bombardments were essential for softening up enemy positions before the ground troops moved in, clearing out entrenched Japanese defenders and creating a safer landing environment.

On June 15, 1944, the U.S. forces began the assault on Saipan. The USS New Mexico and other battleships in the Pacific Fleet began their preparatory bombardment of the island, targeting Japanese fortifications, supply dumps, and artillery positions. The ship’s secondary 5″/25-caliber battery was one of the weapons used during this operation.

The 5″/25-Caliber Battery

The 5″/25-caliber gun, also known as the “five-inch,” was one of the most widely used naval guns during World War II. Though the 5″/25 was not as powerful as the main guns of the battleship (which were 14-inch guns), it still played an important role in providing support during bombardments and in anti-aircraft defense.

The 5″/25 guns aboard the New Mexico were mounted in dual-purpose turrets that allowed for both surface and anti-aircraft fire. These guns were capable of firing high-explosive shells at a relatively high rate of fire. They had a range of about 12,500 yards, making them useful for engaging targets on land as well as in the air.

During the bombardment of Saipan, these guns were particularly effective in targeting Japanese artillery positions and machine gun emplacements, which were dispersed along the island’s coastline and hills. The fire from the New Mexico’s 5″/25 battery was coordinated with other naval assets to help soften up Japanese defenses before the Marines and Army troops hit the beaches.

One of the most significant features of this gun battery was its rate of fire. The 5″/25-caliber guns could deliver a barrage of shells rapidly, providing consistent pressure on enemy positions. This was essential in neutralizing Japanese forces, who were often well-entrenched in fortified positions. The bombardment not only destroyed military installations but also disrupted Japanese command and communication, making it more difficult for them to mount an effective defense.

The Bombardment of Saipan

The battle for Saipan began in earnest on the morning of June 15, 1944. As the landing forces approached the island, the USS New Mexico began firing its 5″/25-caliber guns, along with its larger 14-inch guns, on key Japanese targets. The naval bombardment was intended to pave the way for the Marines who were landing on the beaches.

The New Mexico’s fire was not only instrumental in clearing the way for the ground forces but also played a vital role in suppressing Japanese fire from the land. The island was heavily fortified with bunkers, gun positions, and supply depots, all of which were ideal targets for the ship’s bombardment.

The 5″/25-caliber guns proved their worth during the bombardment. While the larger guns of the ship provided devastating firepower, the 5-inch guns were used for more specific, tactical targets, including suppressing machine-gun nests, artillery positions, and smaller defensive fortifications. The fire from the New Mexico’s guns helped to achieve a rapid breakthrough for the American forces, preventing heavy casualties during the landing and securing a foothold on the island.

The Aftermath of the Bombardment

Following the successful landing and the subsequent hard-fought battle on the island, the United States was able to capture Saipan by July 9, 1944. The capture of the island was a critical victory, as it allowed American bombers to operate from Saipan, bringing them closer to Japan’s home islands. This victory played a pivotal role in the Allied strategy to isolate Japan and pave the way for future attacks, including the eventual bombing of the Japanese home islands.

The USS New Mexico, like many of the ships involved in the bombardment, continued its service during the remainder of the war. While the ship’s 5″/25-caliber guns were just one of the many weapons used during the operation, their contribution was vital to the success of the invasion.

Conclusion

The bombardment of Saipan, including the fire support provided by the USS New Mexico’s 5″/25-caliber battery, was a critical moment in the Pacific War. The fire from the battleship not only helped to pave the way for the American ground forces but also demonstrated the effectiveness of naval fire support in modern warfare. The 5″/25-caliber guns, while not the most powerful weapon on the ship, proved their versatility and value in neutralizing enemy positions and supporting the Marines and Army soldiers landing on Saipan. The success of the operation would be one of the many milestones in the Pacific campaign, leading to the eventual defeat of Japan.