German Submarine Research And Development During The Inter-War Years AUTHOR Major Edward N. Rohloff, USAF CSC 1989 SUBJECT AREA - History EXECUTIVE SUMMARY TITLE: GERMAN SUBMARINE RESEARCH AND DEVELOPMENT DURING THE INTER-WAR YEARS As World War I drew to a close, Germany was left defenseless. The Treaty of Versailles prohibited the German people from maintaining virtually any type of military forces. Germany's U-Boat forces were completely dissolved. Only a token number of antiquated surface vessels were allowed in operation. The post war years brought great attention to the submarine from the military forces of the day. Submarines had played an important role in the First World War. In the years after the war, international concern was levied in the interest of maintaining military parity of the world powers. The victors of the war strived to achieve this equality through conferences dealing with arms limitations. Germany was ignored at these talks because of her status as a result of the treaty. Germany, however, began clandestine activities in an attempt to retain some of the technology which she had garnered during World War II. In due time Germany had not only managed to continue research and development but had also actually trained some crew members in the U-Boat business. When Adolph Hitler came to power, Germany had only to reveal her secret and she was back in the business of being a viable sea power. This complete evolution allowed Germany to quickly build her forces in preparation for the aggression which she was about to display on the rest of the world. Had it not been for the resistance of a few key players in this building process, Germany may have been much stronger at the onset of hostilities. Her U-Boat forces may very well have led her to much greater heights. German Submarine Research and Development During the Inter-War Years OUTLINE Through relentless clandestine operations Germany would retain and actually improve her U-Boat technology base despite the restrictions of the Treaty of Versailles. I. Post World War I Awareness A. International attention of submarine warfare B. Attempts to regulate naval forces II. German Research and Development of U-Boats A. Clandestine Operations B. Actual production III. Establishment of the Naval U-Boat Arm A. Tactics development B. Force Structure German Submarine Research and Development During the Inter-War Years The First World War demonstrated to the world that submarine forces could be an essential ingredient to any country's naval and overall warfighting capability. German U-Boats wreaked havoc on Allied surface ships throughout the war. Hundreds of thousands of tons of shipping were sent to the depths of the seas as a result of this born again weapon system.1 Submarines had been in use for decades, but never before had they been used with such devastating results. Germany's use of submarines during this period overshadowed any other country's attempts at submarine warfare to date. Germany would demonstrate during World War II how the U-Boat had become an integral element of her blitzkrieging war machine. With the end of World War I, the Treaty of Versailles forbade Germany of possessing any U-Boats and dictated that the Imperial Navy be reduced to only a handful of very old surface ships.2 Germany however would not forget the importance of the U-Boat as an essential element of military might. Through relentless clandestine operations Germany would retain and actually improve her U-Boat technology base despite the restrictions of the Treaty of Versailles. The inter-war years between 1918 and the early 1930 `s produced international concern and attention toward submarine warfare. The world remembered the successful campaigns of the German U-Boat fleet during World War I. Some recalled the thousands of lives lost and the perils of those left stranded in life boats after submarine attacks. For others, the submarine was an instrument of power and a must for any viable military force. A conference in Washington D.C., in October of 1921, attended by representatives of the United States, Great Britain, France, Italy, and Japan addressed the topic of limitations on naval armaments. 3 The size and operations of submarine forces were barely mentioned. Great Britain wanted to abolish their use altogether, but the other conference members disagreed. Again in 1930 the aforementioned countries sent representatives to confer over naval issues. This conference took place in London. 4 The result of this debate was a lame international policy, embodied in the London Protocol of 1934, which established a set of rules for submarine warfare: 1. The submarine must surface before attacking. 2. Crews and passengers had to be guaranteed safety. They could not be abandoned in small boats on the high sea. Either they had to be taken aboard the submarine (which was impossible in terms of space), or the submarine captain had to hail a neutral ship to take them aboard (most improbable), or the ship had to be let go. 3. Merchant ships were not to be armed. 4. Merchant ships were not to use radios to call for help or warn other ships at sea about the submarine.5 Obviously the rules of the London Protocol would not stand up during hostilities. World powers at this time between the great wars acted as if they had blinders on where Germany was concerned. The Treaty of Versailles had forbidden any build up of German military forces. As a result of this, England, Japan, France, Italy, and the United States failed to pay heed to Germany's technological advancements in U-Boat construction during these years. The so called world powers did not invite Germany to the international meetings designed to regulate the naval forces of these countries. Germany, however, had other ideas. At the close of World War I, Germany was concerned about national defense and the limitations of the Treaty of Versailles. How could she be expected to dissolve her navy and leave her coastlines undefended? Despite efforts to retain some of her military might for national defense, Germany was directed to dissolve the U-Boat Inspectorate and the U-Boat Office.6 Constrictions imposed on Germany by the treaty led to clandestine activities masterminded by the great armorer of Germany, Gustov Von Krupp.7 The Krupp family with its international connections already had the framework to continue the work of the U-Boat engineers and architects. In 1922 Krupp dispatched the first of 40 German engineers to a Dutch company at the Hague where they found employment drafting U-Boat blueprints.8 Krupp managed this business venture to respectability by selling shares in this new company and also by sending submarine blueprints to Japan, Spain, Turkey, Finland, and Holland.9 Before long, a perfectly respectable international business had become a breeding ground and training environment for Germany's ever growing U-Boat engineering and design capability. Two U-Boats were built for the private account of that Dutch firm - a 250 tonner at Abo in Finland, which was later delivered to the Finnish Navy, and a 500 ton boat built in Cadiz, which the Turks took over. German engineers, dockyard experts, and naval officers helped to supervise the submarine construction. Small groups of men - never more than half-a-dozen at a time - travelled incognito to Spain and Finland. Naval officers of the executive and the engineering branches, and naval contractors, posing as businessmen, students, fitters, or employees of the Dutch company, went there to relearn the problems of U-Boat handling.10 Orders for submarines were received from around the world. The next logical step took place. German engineers well schooled in the design of the U-Boat soon became experts in construction. Lessons learned from World War I construction were applied and a much more efficient and capable class of boats emerged. Germany was again cornering the market in U-Boat design and construction despite the restrictions imposed on her after the war. The next step toward rebuilding the U-Boat arm of the navy was to covertly train sufficient numbers of crewmen in U-Boat operations. This was done by the establishment of the Anti-submarine Warfare School at Kiel. What appeared on the surface as a center for a dozen officers and about sixty enlisted men as training in navigation and naval art and science indeed was the beginning of the new U-Boat force. The men trained in civilian clothes in a very low key environment. Practical application and actual operations took place in Finland.11 Adolph Hitler had at this time been appointed Chancellor of the German Republic. The German Navy began manufacturing U-Boat parts in secret. Up until this time Germans had not been involved in actual U-Boat production on native soil. A whole series of mysterious, heavily guarded sheds had sprung up inside the Deutsche Werke and Germania shipyards in Kiel.12 The Germans were building submarines, quite illegally under the terms of the Treaty of Versailles. The year was 1934. U-Boats of the type already designed, constructed, and operationally tested by German engineers and crewmen in Spain and Finland were laid to construction.13 Germany's naval rebuilding program was in full swing. On March 16, 1935, Adolph Hitler publicly repudiated the Treaty of Versailles. Germany would no longer conceal escalation and rebuilding efforts of her naval forces. The rest of the world was forced to recognize the emergence once again of the German people as a growing world power. Three months later Germany and Great Britain concluded the Anglo-German Naval Agreement. Under its terms Germany would restrict the strength and size of her Navy to 35 percent of that of the British Navy with exceptions to the size of the German submarine forces.14 The rest of the world stood by and watched Germany rebuild. Adolph Hitler was in full control and appeared to be acting within the terms of international agreements. England's hands were tied as a result of the Anglo-German Naval Agreement. The shroud which had hidden Germany's secret, the illegal building operations, was dropped. By mid 1935, U-1 the first U-Boat of the modern class was brought out, ready to launch. She began her first patrol just forty two days after the signing of the new Naval Agreement.15 The stage was set for the ensuing buildup of the U-Boat arm of the German Navy. Karl Doenitz was selected by the German High Command to take charge of the new U-Boat arm. Doenitz was a World War I U-Boat commander who was captured by the British and spent several months in a British prisoner-of-war camp. Doenitz feigned insanity and was released by the British for repatriation to Germany.16 Doenitz' inter-war years were spent in the German Navy on surface duty. With his appointment to head the U-Boat arm, Doenitz began to conceptualize employment of the submarine force. Commander Doenitz recalled his experiences countering British convoys during World War I. He was convinced that a hunter killer tactic with individual submarines engaging surface ships would not be the most effective utilization of his submarine forces in the next war. He devised the Rudeltaktik (the wolf-pack strategy) in 1935.17 He felt that convoys with their protective escort must be attacked with "packs" of U-Boats as opposed to individual sorties on search and destroy missions. Doenitz' concept of employment was that a single U-Boat would operate on patrol to locate a convoy. Upon sighting a convoy, the U-Boat would disengage the intercept while maintaining contact with the convoy. The pack would then be called in to converge on the prey. The wolf-pack would mostly engage on the surface to take advantage of their speed and maneuverability.18 Doenitz believed that an efficient U-Boat force would have to number approximately 300 boats. He envisioned 100 U-Boats at any one time on station in the North Atlantic. Another 100 boats would be in port in routine maintenance and resupply. The remaining 100 boats would be enroute to and from the patrol areas. This force, he believed would be of sufficient strength to starve Britain to death.19 Doenitz had a difficult time convincing the power structure in Germany of the need for such a large force. Eventually Doenitz was able to convince Hitler and Admiral Raeder, the Commander in Chief of the German Navy, of the importance of increasing the size of the U-Boat forces. On 17 January, 1939, Adolph Hitler approved the Z-Plan. This plan in addition to building multiple surface ships provided for the construction of 233 more U-Boats.20 The construction would not be complete until 1948. When World War II broke out, Admiral Doenitz was in command of just 56 U-Boats.21 Throughout the war years German industry would produce scores of U-Boats. However, Admiral Doenitz would never command the size of force he felt necessary to wage a decisive campaign. The foresight of a few key influential individuals enabled Germany to maintain a U-Boat technology base after the First World War despite the worlds attempts to eliminate her warfighting capability. While the rest of the world attempted to achieve military parity in efforts to preclude another major confrontation, Germany gradually rose from her postwar status as a second class powerless nation to a nation capable of once again producing the machines of war. Her covert operations in U-Boat engineering and production enabled her to be prepared for production when Adolph Hitler came to power. The chain of events which ensued overwhelmed Admiral Doenitz' U-Boat production projections. The number of boats Doenitz had in his command never met the need for his concept of employment. Therefore he was never able to fully implement his plan of action. One can only guess at the outcome of World War II had Doenitz had his 300 U-Boats at the beginning of hostilities. ENDNOTES 1. Richard Garrett, Submarines (Boston: Little, Brown and Co., 1977) ,p.61. 2. Ibid., p.69. 3. Ibid., p.69 4. Ibid., p.71 5. Edwin P. Hoyt, U-Boats (New York: McGraw Hill, 1987),p.2 6. Eberhard Rossler, The U-Boat, tr. Harold Erenberg (Naval Institute Press, 1981),p.88. 7. Garrett, p.72. 8. Douglas Botting, The Seafarers: The U-Boats (Alexandria, Virginia: Time-Life Books, 1979),p.76. 9. Garrett, p.72. 10. Wolfgang Frank, The Sea Wolves (London: Weidenfeld and Nicolson, 1955) ,p.9. 11. Hoyt, p.4. 12. Frank, p.10. 13. Vice Admiral Sir Arthur Hezlet, The Submarine and Seapower (New York: Stein and Day, Publishers, 1967),p.118. 14. David Mason, U-Boat The Secret Menace (New York: Ballantine Books, Publisher, 1968),p.10. 15. Hoyt, p.5. 16. Frank, p.13. 17. Hoyt, p.7. 18. Garrett, p.78. 19. Mason, p.13. 20. Rossler, p.11. 21. Hoyt, p.9. BIBLIOGRAPHY Botting, Douglas. The Seafarers: The U-Boats. Alexandria, Virginia: Time-Life Books, 1979. Frank, Wolfgang. The Sea Wolves. London: Weidenfeld and Nicolson, 1955. Garrett, Richard. Submarines. Boston: Little, Brown, and Co., 1977. Hezlet, Vice Admiral Sir Arthur. The Submarine and Sea Power. New York: Stein and Day, 1967. Hoyt, Edwin P. U-Boats. New York: McGraw Hill, 1987. Mason, David. U-Boat The Secret Menace. New York: Ballatine Books, 1968. Rossler, Eberhard. The U-Boat. Tr. Harold Erenberg. Naval Institute Press, 1981.
