Submarine warfare and intelligence in the Atlantic and Pacific in the Second World War: comparisons and lessons learned for two opponents

ABSTRACT A unique study has been undertaken examining the impact of submarine performance and countermeasures in two different oceans during the Second World War using official declassified data. This analysis is for two distinct zones of combat, using essentially and simultaneously the same offensive technology (submarines) and defensive strategies (intelligence and signal de-coding). It has been previously shown that learning curves are present in the rate of losses in conflicts between opponents. This analysis compares for the first time the performance of German submarines in the Atlantic attacking Allied convoys with that of American submarines operating in the Pacific against Japanese shipping. For these two theatres of conflict, the rates of sinking of target ships are evaluated, which therefore includes the effectiveness of ‘communications intelligence’ (Comint) and ‘decryption intelligence’ (DI). The choice of the relevant risk exposure measure can be derived and proved. Surprisingly, no difference was found in the warfare sinking rates achieved by the submarine fleets operating in these two vastly different oceans. This similarity must be due to common random search and human learning techniques, and not to employing differing Comint and DI technology. This result has significance to present-day warfare studies and to search theory.