Which Submarines Dominated WWII: US or Japanese?

The question of which submarines were better in WWII often revolves around the comparative performance of the United States and Japan. While the Japanese Submarine Force boasted a wider variety of designs and superior torpedoes, the U.S. Submarine Force ultimately had a greater strategic impact. This article explores the key factors that influenced the performance of both fleets.

Submarine Capabilities: A Comparison

During WWII, the submarine forces of both the United States and Japan were formidable. However, they operated under different doctrines and faced distinct challenges.

Japan's submarine force, although numerically superior, had a narrower focus on capital ships and lacked the anti-shipping emphasis that characterized the U.S. submarine strategy. This meant that while Japan had more types of submarines and exceptionally deadly torpedoes, the U.S. submarines had a more pervasive impact on the war effort due to their effective anti-shipping campaign. The U.S. heavily depended on maritime logistics, and its submarine force inflicted significant damage on the Japanese supply lines, severely crippling their war effort.

Torpedoes and Their Impact

When discussing the performance of submarines during WWII, the type of torpedoes used plays a crucial role. The Japanese Type 93 ‘Long Lance’ torpedo was considered one of the best anti-surface ship torpedoes of the time, known for its speed, depth, and range. However, the effectiveness of a torpedo depends not only on its quality but also on how it is utilized. The U.S. submarines were not only equipped with superior torpedoes but also had advanced technology and radar systems that significantly enhanced their combat capabilities.

Technological Advantages: Radar and Depth

The use of radar significantly differentiated the U.S. submarine force from its Japanese counterparts. The U.S. fleet submarines were equipped with several radar technologies that provided a decisive advantage. Here’s a detailed breakdown:

SD Radar - An early form of air search radar, it allowed submarines to detect incoming aircraft without providing much detail about their range, speed, or direction. This was still a valuable asset as it gave subs the chance to dive and evade. SJ Radar - Introduced in mid-1942, this directional radar could sweep the seas for surface targets. Since Japanese destroyers did not receive radar systems until late in the war, the American subs had a significant advantage in surface search and engagement. PPI (Plan Position Indicator) - This radar provided an electronic map of the surrounding area, which was a more intuitive and precise tool for target engagement. This technology greatly improved the accuracy and effectiveness of U.S. submarines. Periscope Radar - Miniaturization allowed U.S. submarines to mount small radar antennas on their search periscopes, enhancing their ability to detect and target Japanese vessels more precisely, even while submerged.

These radar systems contributed significantly to the U.S. submarine war effort. They allowed U.S. subs to operate on the surface during daylight, keeping their batteries charged and extending their operational range. The radar’s ability to detect and track enemy vessels, even those on the surface, at longer ranges provided a significant strategic advantage.

Comparison with Other Nations

While Germany’s Type XXI submarines were advanced in terms of design, they were too late to make a significant impact in the war. The U.S. Balao and Gato-class submarines, on the other hand, were well-equipped and effective from the beginning of the conflict. Their combination of Range, crew comfort, advanced torpedo data computers, and torpedo load, along with their superior radar systems, made them the dominant force in the submarine wars of WWII.

Conclusion

While the Japanese submarines had their strengths, such as a wider variety of designs and superb torpedoes, the U.S. submarines achieved more strategic impact due to their superior anti-shipping doctrine and advanced technology. The availability and effective utilization of radar systems provided the U.S. submarines with a key advantage, shifting the odds decisively in their favor. This analysis underscores the importance of not just the technology but also the strategic doctrine and tactical execution in submarine warfare during WWII.