Between the Wars
By the end of the First World War, using accumulated convoy data from various sources and applying statistical methods British navy analysts easily affirmed the efficacy of the convoy tactic in a modern naval war. Lessons learned during the war also included the tactic of submarine versus submarine, which would evolve gradually in the years ahead.
Merchant ship protection from the U-boat was provided during World War I primarily by patrolling the seas (guarding the sea-lanes) and convoy escorting. Patrolling to counter enemy submarines steadfastly held its place as the primary U-boat countermeasure in the minds of some senior navy personnel in the years after World War I. In spite of convoying’s documented successes, the reason for that bias toward patrolling perhaps was because it could be viewed as an offensive navy posture and more in keeping with navy aims.
The convoy concept made the enemy submarine confront defended merchant ships rather than independent ships defenseless against the U-boat. Patrolling expended scarce resources searching for enemy submarines in large ocean areas and in unknown locations without adequate tools for detection and localization of the U-boat, whether submerged or surfaced by day or night.
Convoying was a positive approach to resolving U-boat interdiction of merchant ships; it brought the enemy to a defended target. In the interim years, the subtle aspects of the convoy were not always easily grasped by the military and elected officials. The effectiveness of convoying was available in the records.
The victorious countries involve.d in the war were determined to keep the hard-earned peace. A series of international peace conferences and treaties were held during the period 1921 to 1936. The reduction of capital ships was a main consideration. At the same time, submarines and their weapons steadily improved. In several countries, research was undertaken to better the methods for detection of submarines. Progress in this area would benefit both patrolling and convoying in the event of a future naval war.
Without the urgency of a wartime environment, planning and preparing for navy convoying of merchant ships in time of war did not present itself as a critical issue nor one generally of much interest during the 20 years of peace. The nonconformist aspects of submarines and their use compared to surface craft came to national and international attention primarily in arguments concerning the abolition of submarines or restraining submarine actions towards merchant shipping during wartime. Full acceptance of submarines as an integral part of the panoply of naval weapons was not held in all quarters of the world’s navies in spite of their increasing number.
In several countries, some of the antisubmarine warfare ongoing research focused on the development and implementation of acoustic detection of submarines. If successful, this was seen by some as a means to remove the convoying requirement.
The ambivalence of certain naval professionals regarding submarines in this period while the submarine and its weapons were developing tended to obscure convoying and the acquisition of the necessary resources for successful implementation in the event of war. A measure of the necessary anti-submarine resources to help defeat the U-boat and sink 200 U-boats in World War I has been estimated to include 5000 ships. Hundreds of miles of steel nets, and a million depth charges, mines. bombs, and shells.
National and international Naval Concerns 1919-1939
Disarmament was of considerable importance starting with the early post-War years. War was unthinkable during the decade after the War and beyond. The enormous debts of the vanquished and the victors alike and the excessive loss of lives and casualties were strongly perceived and remembered. There were multiple reasons for disarmament, some of safeguard peace, and some driven by economic considerations, which worsened during the 1920s.
A view as to how the submarine was held in the minds of some is expressed in a paper given in a March 1919 British War Cabinet meeting held to discuss future warfare research. Lord Weir, Secretary of the State for the Air Force asked: “What would the House of Commons say to the creation of a new big institution for Research in connection with warfare at a time when we may be presumed to be establishing peace conditions on a stable footing? If, for instance, the submarine were definitely ruled out of warfare, would not the strongest argument in favor of the Admiralty scheme disappear’?”
Starting in 1920, The Ten Year Rule prevailed in Britain. The rule implied that the British Empire would not be engaged in any Great War during the next 10 years. It provided a reason for reducing military expenditures and continued several years beyond 1930. All the armed forces were impacted by reductions in support.
Views regarding the submarine by naval and government figures during the decades between the world wars were diverse with generally no consensus among the five powers: France, United States, Great Britain, Italy, and Japan. A comment regarding submarines was made at this time ” … that such methods as the Gennans used will never be employed again, but need not be feared that any civilized nation would adopt them … ”
Moreover as early ~ 1922, with Germany banned from making submarines and other military weapons by the Versailles Treaty, German civilians were designing new German submarines for a Dutch firm, a front for certain German shipyards, located in The Hague. Later, experimental models were constructed in Holland and Spain.
Britain’s hesitant position regarding submarines in the postwar period was frequently voiced ~ favoring the abolition of the submarine as a weapon of war. This view was taken at the Versailles Peace Conference, in the 1921-22 Washington Peace Conference, in 1925, and at the London Conference in 1930 and the last London Conference in 1936. Beyond abolition of the submarine, a position aimed at reducing the international submarine tonnage or restricting submarine activities was taken, mostly without great success.
In 1927, the British Director of Naval Intelligence focused on a possible reason for this anti-submarine position by Great Britain ” … trying to influence other governments against submarines because Britain herself has ‘more to fear from submarines than has any other power .”
Article 22 of the London Naval Treaty of 1930 agreed to by the United States and Great Britain approached the submarine problem by stating that in time of war “… a warship, whether surface vessel or submarine, may not sink or render incapable of navigation a merchant vessel without first having placed passengers, crew and ship’s papers in a place of safety … ” A further consideration provided that merchant ships would not be armed during peacetime. Later, the Third Reich officially agreed to this article on 23 November 1936.
Hitler’s coming to power in 1934 was immediately followed with his flaunting of the Versailles Treaty by Germany ordering 24 of the previously mentioned Finnish model submarines and two of the Spanish version.
A body of naval opinion preserved the anti-convoy viewpoint throughout the 1930s. A March 1935 House of Commons speech by Lord Stanley of the Admiralty reflects such. Stanley assured the House that the convoy system would not be introduced at once on the outbreak of war. All the pre-April 1917 arguments against the need to have merchant ship convoying were recycled 18 years later in 1935.
The Anglo-German Naval agreement was reached on June 18, 1935. Germany was once again legally permitted to build and operate a fleet of submarines. The next month Winston Churchill observed that the German navy was meager. Other comments included “Today Germany has no submarines.” Germany launched the first U-boat four months later. The following year the London Submarine Protocol, 3 September, cited that Germany would adhere strictly to the international prize law, which provided for safety of merchant ship passengers and crews in time of war.
During the 1920s and ’30s, submarines and airplanes continued to be regarded as fleet reconnaissance and attack elements. However, naval strategist French Admiral Raoul Castex envisioned renewal of the use of submarines as commerce raiders.
The late 1930s found increasing numbers of sophisticated
submarines with improved weapons on the international scene. The submarine’s record as a successful merchant ship raider was available from the preceding war. It would seem that this would lead to positive national positions regarding convoying merchant ships and with it appropriate planning and preparation in the event of war.
Planning for the convoying merchant ships finally received some attention in Britain in 1937. The Air Staff and the Admiralty after further arguments agreed that convoying should be adopted in the event of war but only if the enemy resumed unrestricted submarine warfare. This allowed the Admiralty to create a worldwide shipping control organization, and by 1939 the planning was well advanced.
Acoustic Detection of Submarines
Modest improvements in the acoustic detection of submarines were made on both sides of the Atlantic by November 1918. In England and the United States leading scientists and engineers, including Nobel award winners, turned their attention to solving the problem of submarine detection. By the end of World War I, submerged submarines could be located. Some of the unresolved equipment limitations included enemy submarine depth determination, detecting in rough seas, and range. Also, the vagaries of acoustic propagation in seawater were yet to be determined.
After the war ended, England continued investigating acoustic detection at a secret level. Similar work was undertaken in the United States. Because the detection equipment was classified-secret, sharing of information did not occur prior to 1939. Equipment testing with submarines under realistic conditions was not substantial.5 The British acoustic detection equipment was known as Asdic (an acronym). It was advanced compared to the World War I equipment but limited in its capabilities. Civilian and naval observers of the equipment tended to become over optimistic. Some erroneously concluded that enemy submarines would not be a problem in the event of wars because of availability of the equipment.
Some comments made by Winston Churchill in Gathering: Storm about Asdic are illuminating. On June 15, 1938, Churchill was on board a destroyer for an Asdic demonstration with Royal Navy submarines as targets. In 1948, Churchill noted that in 1938 he and others overrated the capability of the underwater acoustics detection of enemy submarines. The performance I imitations of the early systems were not fully grasped by the fall of 1939. The optimism regarding the expected performances of Asdic led to a lack of preparation to make up for the equipment limitations which became apparent.
Advancement of military technology in the United States during the long peacetime period was slow, due heavily to lack of fiscal support for research and development. The funds available for military technology development were a small percentage of the overall military expenditure. Research project security classification and the independence of the various branches of the armed forces were additional barriers to progress. Academic and private sector scientific and engineering personnel did not have broad participation with the current government military research laboratories. The Naval Research Laboratory opened in Washington in 1923, and in conjunction with several industrial activities became the center for the development of enemy submarine detection equipment. By 1933, fifteen destroyers and five submarines were equipped with echo ranging acoustic detection equipment. At the end of the decade, additional progress was made regarding the numbers of installations and the beginnings of adequate training for equipment operators and use were initiated.
Navy problems and priorities during the years between the wars placed merchant ship convoying in an obscure role. Mahanian thinking with the capital ship at its focus still prevailed. Aircraft and aircraft carriers began to be acknowledged, and some inroads in naval thinking and planning were made in these areas during these years. Decreased naval budgets and the high costs and years of construction time for the large ships placed construction of the smaller ships for convoy escorting in a low priority position. The shorter time requirement for the building of convoy escort ships may have accounted for their lower priority.
The high performance expectations of the 1930s submarine detection equipment as cited above led to a downplaying of the enemy submarine’s capabilities. In retrospect, even if the performance was as anticipated, there were only limited numbers of vessels equipped with the detection equipment. as a further problem, the number of skilled operators was insufficient.
As late as November 1938, a retired German Vice Admiral noted in an article “nothing substantial has as yet been done in England (and equally in France) for the protection of oceanic convoys.” Soviet Admiral Gorshkov, observed in 1976 that the ” American Navy came into the War (II) totally unprepared to protect merchant vessels from submarine strikes.”
Even though analysis of convoy performance presented evidence that convoying did not cause excessive delays in shipping and did save lives and ships, there were those in the Admiralty and in public office in 1939, twenty years later at the start of World War II, who were overtly not pro-convoy. As late as early 1942, some U.S. Navy personnel were initially not enthusiasts for convoying. A quotation in Morison “when the U-boats hit our coast in January 1942, we were caught with our pants down through lack of antisubmarine vessels” is concise. In February, Britain gave the United States 24 trawlers and 10 corvettes; and these additional escorts allowed small East Coast convoys during the day and putting into harbor at night.
In both World Wars, merchant shp convoying was pivotal to eventual success. During the first War, the U-boat and course de guerre was unexpected. This and lack of resources contributed to delays in implementing broad merchant ship convoying.
Reasons for the neglect of merchant ship convoying in naval planning and preparation during the forgotten years are unclear. However, they do raise the question of what equally significant naval strategy or tactic is overlooked today.
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