US Submarines: How Did the ‘Silent Service’ Win WWII in the Pacific?

Big guns thinking dominated the 1930s US Navy. The era of the battleship carried on as it had since before the Great War, with even aircraft carriers being second fiddle. The might of the battleship still meant power projection and prestige. Submarines played the role of scout and ambush – not a role an aspiring naval officer sought out. No change would happen until America’s violent introduction into World War II. In 1939, the US Navy had less than 50 submarines, many built in the mid-1920s. Commissioning of the first American submarines started in 1900. One of the first examples was the USS Octopus.

Japan’s December 7th bombing of Battleship Row at Pearl Harbor with airstrikes signaled the end of battleship dominance. It also changed the scouting and ambush role of American submarines. Now, the submarine force began to pivot, concentrating resources on Japan’s merchant marine. But, problems with equipment soon appeared.

Creaks, Groans, and Duds

The 1920s submarines, the S-class, went to war first in 1942. Few American submarines stayed in the Atlantic-Germany was a land-based threat. The creaky S-class operated from Hawaii, Midway, the Aleutian Islands, and Australia. Their goal: strangle Japan by preventing ships from reaching the Home Islands. US submarines had a tough 1942. The lost forward bases impacted patrols, as the S-class had short ranges. Bigger submarines came online, slowly replacing the older boats. The submarines patrolled the Western Pacific, looking for targets, but few ships were torpedoed successfully. Frustrations with equipment, captains, and purpose bubbled up even through 1943.

A focus problem showed itself that diluted the Silent Service’s purpose: the submarines had too many roles. Mission roles included weather, supply, attacking enemy warships, and scouting. With only fifty submarines in operation, few could be used to attack Imperial Japan’s merchant marine. Dud torpedoes often angered many crews. The submarines lined up, shot, and waited, usually slower than their targets. Often, torpedoes hit but never detonated, sometimes six times! The torpedoes, the Mark XIV, turned out to be very unreliable, having detonator issues. Higher US Navy Command denied this, stating no problem existed and just use them.

1943 became the year of significant change. Bigger, improved submarines, like the Gato and Balao class, entered service with better speed, detection equipment, and weaponry. They even came with water distilling plants, allowing crew showers! Better-trained crews used these improvements, becoming more aggressive. The pace of sinkings quickly began to climb.

1944 became the year the Silent Service cemented its reputation in US Navy history. Submarines came online facing inadequate Japanese antisubmarine tactics as eighty submarines alone were built in 1944. More Japanese ships went to the bottom in this unequal duel than in any other year. American submarines prowled the waters around the Philippines and off southern China, hitting without warning. Japan’s merchant fleet traveled through here, supplying the war effort. The submariners adopted wolfpacks, a tactic created by the Kriegsmarine, groups of submarines operating together. Their goal was to starve Japan of fuel, food, and supplies.

Despite the Imperial Navy’s best efforts, one and a half of the ships went to the bottom daily. Total tonnage sunk rose to nearly three million tons, translating to six hundred merchant ships. The Japanese nicknamed the sea northeast of the Philippines “the Sea of the Devil.” And rightly so. Thousands of Imperial Army soldiers drowned, close to or over 100,000, depending on the source.

The Silent Service’s success meant less for Japan’s Home Islands. This was compounded by American aircraft flying from captured Philippines airfields. Total imports plummeted from 1941’s twenty million tons to ten million tons by 1944. That slide stalled by August 1945 with zero imports. By 1945, Japan rationed food, cutting caloric intake to less than 2,000 calories. Mines laid by submarines and planes increased the risk to ships, too.

The Cost

The Silent Service started World War II with fifty boats, most a decade old. As America’s economy ramped up, it added two hundred more submarines. At some point in 1944, the western Pacific was almost inundated with American submarines. Fifty-two American submarines were sunk, or one in five men died, for a total of 3,506. Surprised in 1941, the Silent Service bounced back, its tactics equaling Germany’s U-boat success. Without such methods, the war would have dragged on.