Submarine Warfare in Pacific and How it Affected Supplies

By Aidan Totten

The Early YearsDuring the early years of the war, U.S.

submarines were almost entirely ineffective. This was due in part to the strategy employed by the Allied powers. Submarines were the only thing left to oppose the Imperial fleet in the Pacific, the major battle fleets held in reserve. Seeing as only 12 of the 29 submarines were the “best” class of submarines that the U.S. had at the time, the submarines in the Pacific were severely outclassed. On top of that, poor military intelligence, poor training, bad torpedoes, and bad luck, combined to make the worst possible conditions for the Allied submarine fleet(“World War 2 Submarine Warfare”).

The Early Years (Continued)As the Imperial fleet closed upon the Allied forces in the Pacific, the submarines succeeded making contact with enemy forces not once, but 45 separate times. These attacks were almost entirely ineffective, and only sunk a total of 3 freighters before the Imperials reached Manila, the closest U.S. military base to Japan in the Pacific.

Improvements to the SubmarinesLocating the enemy was an extremely important part of fighting them. However, until late 1942, submarine commanders were forced to rely on sight. As a result of that, it was hard to find the enemy fleets. When the SJ radar came out, it enabled submarines to locate enemy fleets well before they could be seen. The buggy radar was a incredibly useful tool placed under the submarine commanders command. When the new Gato-class submarines started replacing the old submarines at the same time, it was obvious the Allied forces were investing in submarine warfare the same way Germany had in World War One.

Improvements to the SubmarinesOn top of the improvements made to submarine warfare itself, both torpedoes and intelligence also had major breakthroughs. Torpedoes, which previously had a lot of troubles with actually exploding on contact, had the problem fixed with the introduction of an improved firing pin. Almost instantly, there was a major increase of the number of ships sunk. ‘Ultra’, a new intelligence system, gave Allied code-breakers to forward anything that might effect submarines directly to the submarines.

It Starts to ShowOnce the upgrades were made there was a huge increase in the effectiveness of submarine war patrols. In August, when the first surface radar was installed in the submarines they sunk a total of 76,652 tons of shipping. After using the new systems in 1943 for a year, the submarines managed to sink a total 1,366,920 tons of shipping. In 1944 the war patrols sunk over 2,000,000 tons of shipping. After 1944 the majority of Japanese supply ships had been sunk, resulting in an almost 200% decrease in the tonnage sunk.

The Supplies"Bauxite imports fell off 88% just between the summer and fall of 1944. In 1945, pig iron imports plunged 89%, pulp 90%, raw cotton and wool 91%, fats and oils 92%, iron ore 95%, soda and cement 96%, lumber 98%, fodder 99%, and not one ounce of sugar or raw rubber reached Japan.“(navy-mil) As an island nation, Japan required many thousands of tons of supplies to support it. Pig iron and iron ore, especially, are very important to any military. Iron is used in building ships, cargo containers, guns, any number of military supplies. Raw cotton and wool is used for uniforms, and fodder raised livestock.