CONVOY: THE FORGOTTEN YEARS 1919-1939 Part I

Earlier Convoys

Convoying merchant ships at sea to protect them from marauders has been an almost intuitive naval tactic possibly since the Phoenicians. In 1673, Samuel Pepys, then Secretary of the Admiralty Office, instituted a convoy system to protect British trade from damage by Dutch privateers. Convoying was certainly successfully achieved during the age of fighting sail in the 16111, 17’h, and 18’h centuries against the surface raiders called cruisers. The British Convoy acts of 1793 and 1798 declared it illegal for Britain’s overseas commerce to proceed unescorted in wartime in the age of sail. There was a three hundred-year custom of convoys in Holland, France and Great Britain.

Regarding Convoy

Examination of acoustic detection of enemy submarines during both World War I and II brings one’s attention to convoying merchant ships. With a long and successful historical record of navies directly protecting merchant ships, it might be assumed that this tactic would be quickly invoked in a twentieth century war. Yet during the first several years of World War I, there were English military and civilian leaders and other members of the Allies who, in the face of available evidence favorable to convoying merchant ships, dissented regarding the need and the advantages to be gained by its implementation. Although begrudgingly, merchant ship convoying was implemented by the Allies May 1917 and was hugely successful for the remainder of the war.

After the armistice, November 1918, following the quick success of convoying during the last one and one half years of World War I, the tactic and consideration of its planning or readiness seem to have been put aside or forgotten. Further, as naval historian Captain S. W. Roskill, RN noted ” … not one exercise in the protection of a slow moving mercantile convoy against submarines took place between 1919 and 1939.” The negative attitude toward merchant ship protection at the beginning of World War II still persisted in some quarters.

Submarine Century Begins

A century of submarines began in April 1900 when the newly formed Electric Boat Company and one of its subsidiaries, the John P. Holland Torpedo Boat Company, sold the submarine HOLLAND VI to the United States Navy. This was a landmark event, establishing the submarine on the international scene. The successful submarine and Holland’s patents for their construction provided the basis for an extraordinary interest in submarines and submarine building by most of the world’s leading countries. By the eve of World War I fourteen years later, there were 400 submarines in sixteen navies armed with torpedoes, deck guns, and mines.

By 1900, worldwide naval thinking was strongly influenced by the writings of Alfred Thayer Mahan, an Annapolis graduate, long-time career officer, and teacher at the U.S. Naval War College whose books on naval strategy were accepted by the naval elite in all the maritime powers. Mahan’s teachings were focused on single, decisive, offensive naval engagements with enemy battleships. The concept of a clash of the modem armadas came in part from his widely read and accepted conclusions in The Influence of Sea Power upon History· 1660-1783 (1890) and The Influence of Sea Power upon the French Revolution and Empire 1793-1812 (1892). The unprecedented technological changes in ships and armament made the scene in World War I vastly different from the world of sail so well understood by Mahan. Acceptance of the submarine as more than a coastal defense craft and an appreciation of its potential as an offensive naval craft would require new generations of naval officers in the post-Mahan era.

On April 20, 1904, Admiral Sir John Fisher, First Sea Lord and creator of Britain’s dreadnought fleet, made a most prescient comment relative to submarines when he said “In all seriousness, I don’t think it is even faintly realized … the immense impending revolution which the submarine will effect as offensive weapons of war.”

The same year, extensive at sea exercises were held off Portsmouth, England in Spithead strait. Six recently completed British submarines of the Holland design, now equipped with a periscope, were part of the operation. It quickly became apparent that capital ships involved would require extensive destroyer screening to protect them from the submarines. Alarm over the submarine’s effectiveness was heightened by the fact that there was no method for detecting a submerged submarine (even though when totally submerged they were vulnerable to mines). No further consideration was given to antisubmarine defense until the War. The submarines fared well in the exercise.

Later, on the brink of World War I in 1913, Fisher wrote a memorandum, “The Submarine and Commerce,” and noted • … if the submarine is used at all against commerce, she must sink her capture.” Among the higher echelons including Winston Churchill then First Lord of the Admiralty, First Sea Lord Prince Louis of Battenberg and Commodore of Submarines Roger Keyes, there was opposition and lack of acceptance of Fisher’s view about submarines sinking their foes. Fisher was somewhat alone in his views at the time but the early conduct of the U-boat commanders in the opening months of World War I supported Fisher’s observation.

A well-turned comment regarding submarines at this time appeared in a history of oceanography written by Susan Schlee. At the onset of World War I, that United States, France, and Britain seemed to have taken the advice offered a Prime Minister by a First Lord of the Admiralty in 1804, on the occasion of seeing Robert Fulton’s plans for a submarine: “Don’t look at it, and don’t touch it. If we take it up other nations will, and it will be the greatest blow at our supremacy on the sea that can be imagined.

In spite of historical evidence favorable to convoying, the Allies in World War I waited nearly three years until April 1917 to invoke convoy as a way to effectively curb the very successful U-boats sinking of merchant ships. Earlier in February, there were 140 U-boats involved in unrestricted warfare. The effect of German submarines sinking one of every four merchant ships leaving England was catastrophic. In addition to the extreme death toll, the loss of many ships and their cargoes produced a number of severe shortages. By April, England’s heavily-imported food supply was down to sixty days and in June, oil essential to both military and industrial needs was down to a three month supply. During the twenty-one years between the two World Wars, the submarine improved in every respect along with its weapons and in numbers. Fully adequate resources for broad implementation of merchant ship convoying were not immediately available in Great Britain at the start of World War II. Although full United States participation in the new war was delayed for more than two years, ample resources for merchant ship convoying would be in short supply until 1943.

Slowness to respond to the U-boat havoc at the start of World War I may possibly be laid to the low regard in which the gradually developing and evolving submarine was held. An item in print in 1902 referred to the submarine as not an honest weapon. Other comments were also demeaning. The underwater craft, small and lacking even some of the elementary needs for adequate crew habitability, was held in derision by some. To others, the submarine was identified with coastal defense and the recourse of a nation with a second rate navy. Navy culture envisioned itself as an aggressive force, not a defensive one; and submarines were not viewed as vital in the offensive concept yet by some, the submarine was seen as a craft that could undermine navies.

In Some Principles Maritime Strategy (1911), Sir Julian S. Corbett observed that commerce raiding was not likely to be strategically decisive so convoys would be unnecessary. He appreciated the role that submarines would play against capital ships. However, he did not grasp the extent to which submarines would become the cruisers of the future.

Flawed perception of the then narrowly-practical submarine a little more than a decade on the international naval scene revealed its strongest feature when German U-boats adopted the guerre de course approach to offensive action. This found the Allies totally surprised and unprepared with regard to countering the U-boat’s success. In 1915, when Germany was the first to launch unrestricted submarine warfare, even those naval officers versed in submarine warfare as it was understood at that time were disconcerted.

Previously, it was understood that submarine warfare would be restrained by maritime law and the unacceptable ethics involved in submarine sinkings. In some instances, either using gunfire or placing an explosive charge would finish off the merchant ship under attack by an enemy submarine. This provided an assured sinking. International law at the start of the war required verification of cargo by an enemy submarine prior to combat engagement. Litigation regarding some World War I U-boat sinkings of merchant ships continued into the 1920s.

U-boat accomplishments and the beginnings of antisubmarine warfare (ASW) were concurrent. The concept of submarine against submarine had its origin in the search for ways to counter the U-boats in the desperate times of World War I. The remainder of the 20U’ century witnessed the unending development of ASW-always off balance as submarines gained acceptance and were provided with improved operational abilities and better weapons. A further obstacle to success against enemy submarines is the ocean, the submarine’s operating medium. It is not transparent.

World War I

England-German Submarines-Convoy

Within six weeks of England’s declaration of war against Germany August 4, 1914, Germany’s U-boats torpedoed four English cruisers with a loss of more than 1600 lives. By the end of 1914, U-boats successfully moved on merchant ships and asserted rights as their own referees at the scene of the encounter. In addition to the sinkings of merchant ships, the number of ships damaged became excessive and created additional burdens on the already overworked British shipyards. Germany began its first unrestricted U-boat warfare between February and April 1915. Before the first year of the war was over U-boat sinkings out-weighed ship losses to any other weapon. The true nature of submarine warfare was emerging. Tactics and weapons for antisubmarine warfare were not immediately at hand.

Convoying military troopships was invoked immediately. Two weeks after the start of the war, the British Expeditionary Force including men, equipment and stores safely negotiated the crossing to France with the aid of convoying. Hundreds of thousands of Allied troops were successfully transported using convoys between India, Egypt, England, and France. In October, a Canadian contingent of soldiers and equipment in a convoy of more than thirty ships transited unharmed to England. Convoys had not been forgotten. Merchant ships with civilian passengers, crews, and cargoes were not in the purview of the Admiralty’s consideration as candidates for the advantages of convoy. There were occasional exceptions to this approach to conveying.

Arguments against merchant ship convoying focused on several concepts, which were ultimately proved not correct. The large number of merchant ships now needing protection was an additional consideration. In earlier times when convoy had been invoked, the number of merchant ships was considerably smaller. There was misunderstanding regarding the number of escort ships required per convoy. Later, the ratio of escorts per merchant ships proved to be a much smaller number than that originally thought by the Admiralty. The skills of the merchant marine ship captains and crews to participate in convoying were also underrated during these early deliberations. Delays in shipping due to organizing convoys were an additional point of argument.

The tools available for countering the U-boats in the beginning of the war were limited. Visual U-boat sighting was the chief method and confined to daylight. Mines and gunfire were the weapons. Sweeping vast areas of the ocean visually with limited numbers of search vessels to locate a single 200-foot long U-boat, which might or might not be located on the surface, was typical. Earlier, Mahan succinctly addressed the issue by claiming “the results of the convoy system warrants the inference that, when properly systematized and applied, it will have more success than hunting for individual marauders-a process which, even when most thoroughly planned, still resembles looking for a needle in a haystack.” Proponents of this Mahanian view were scarce.

As the war progressed, improved mines, depth charges, and the beginnings of elementary acoustic underwater detection equipment appeared toward the end of the conflict. Radio communications for the searchers were still in a basic stage of development. Blimps, planes, and submarines were used in convoy and antisubmarine efforts before the war ended.

Convoy Deadlock

The British Navy, even with the accumulated evidence of U-boat prowess in the fall of 1916, was reluctant to invoke convoy for merchant shipping. The advantages and potential of the concept of convoy and its subtle ramifications were not understood. The Admiralty’s dilemma in dealing with the U-boat problem and general acceptance of the submarine as a part of modem navies may be viewed by considering the following: the submarine was still a relatively new development and its stealth properties made it unique; the U-boat success as a commerce raider was not expected; and further, as mentioned previously, equipment for combating submarines was not at hand. It was an unconventional weapon intruding on a centuries-old conventional navy. Similar attitudes towards the submarine were held in the United States Navy.

Even in the face of the sinkings the preceding year January 1917 found the Admiralty publishing an official view declining convoy as a requirement for safe passage. John Winton wrote in CONVOY: The Defence of Sea Trade 1890-1990 (1983) “the pamphlet which stated, quite definitely and emphatically, that convoy was not a sound method of defending trade.” Another severe blow to the already jeopardized merchant vessels came in the German announcement 31 January that unrestricted submarine warfare would begin the next day. With forty-six U-boats at sea, extreme losses would occur in the following six months.

The crisis could no longer be ignored. Commitment of scarce resources for convoy escort did not occur until after several more months of negotiation, haggling, and with encouragement from the United States. Rear Admiral William S. Sims, USN, assigned to London to cooperate and keep the United States Navy Department apprised of the British scene, arrived on 9 April 1917. Sims secret departure for England was just prior to America’s entry into the War. Secretary of the Navy, Josephus Daniels, briefed Sims regarding the Wilson administration’s views on the British navy’s performance in the War. Two points were that the British had not been vigorous enough in their efforts to curb the U-boat destruction of shipping and that all ships ought to be convoyed. The convoy dilemma heightened when on the night of April 17 thirty-four ships were sunk.

Shortly after his arrival three days after the American declaration of war, Sims promptly encouraged a study to be undertaken regarding the practical aspects of convoying. The study was quickly completed and acknowledged the practicability of convoying. Sims, a senior and experienced officer, by his maturing pro-convoy stance helped to expedite the resolution by the Admiralty to undertake convoy to counter the U-boats’ decimation of the merchant shipping. His position stated ” .. .It therefore seems to go without question that the only course or action for us to pursue is to revert to the ancient practice of convoy. This can be purely an offensive action, because if we concentrate our shipping into convoy and protect it with our naval forces we will thereby force the enemy, in order to carry out his mission, to encounter naval forces … we will have adopted the essential principle of concentration.” An enhanced program of merchant ship convoying was undertaken within the month.

David Lloyd George, with only a few weeks in office as Prime Minister, was finally able to prod the reluctant Admiralty to adopt convoying as a last resort to stem the huge merchant ship losses to the U-boats. The end of April saw the initial steps by the Admiralty to convoy all vessels (except those above fifteen knots) British, Allied, and neutral. An April 30 convoy from Gibraltar to the British Isles was a success. Transatlantic convoys would be next. Requests for U.S. Navy escort participation were initially greeted with the same reluctance and arguments that the Admiralty had been using. A particular point was the ratio of escorts to the number of merchant ships but eventually this was no longer an issue.

The destroyer with its high speed and torpedoes proved to be the convoy escort’s cornerstone. Sloops, trawlers, old cruisers and old battleships were included in the merchant ship escorts. It was quickly learned that convoys of as many as twenty or thirty merchant ships could be successfully managed. Equipping convoyed merchant ships with arms enhanced safe transits. In the three-month period of May through July 1917, the total losses in convoy and independent losses through U-boat attack in the Atlantic and British Home Waters after the introduction of convoy was 383 ships sunk. Of 8707 ships convoyed, 27 were lost. Independent losses comprised the remainder.

By the following year, 1918, the shipping losses fell by two thirds. Antisubmarine Warfare (ASW) involving Allied resources from Britain, Italy, U.S., and Japan included 400 surface vessels, 216 seaplanes, 85 large flying boats, and 75 blimps. On a manpower basis, it has been estimated that 100 men from the Allies were needed for each German on a submarine. Another evaluation concluded that 25 allied warships and 100 aircraft per U-boat was needed.

The submarine changed the way war at sea was conducted. Enemy submarines complicated the means and character of naval warfare in different ways. The demand for naval resources to prosecute ASW and convoy escort obligations was extreme. Sometimes this led to force dispersion. Convoying was successful in saving ships and lives. In addition to the vast amount of resources, manpower, and platforms, additional time was required to organize the convoys. The speed of transit was slower to accommodate the merchant ships. Calculations indicated a 25 percent loss in carrying capability when convoy is in use. By the end of the War in late 1918, England had between 400 and 500 destroyers in commission to meet the critical needs for convoys and patrols. The U-boats did not control the seas, they denied access. Safe passage came at a price.

As the war ended, ASW patrolling and convoying were being brought to bear. The resources included ships, submarines, airplanes, and blimps. The weapons were mines, depth charges, steel nets, and torpedoes. By 1918, acoustic detection of submarines was in the embryo stage and slowly evolving. Also, it would seem that U-boats and the success of guerre de course would have been indelibly imprinted on future naval thinking and planning. Convoying prevented the Allies from losing the war in 1917. The leading maritime nations of the world would give their attention at varying levels to ASW for the remainder of the century.

As World War II began, the repeated success of the U-boats and availability of the means to counter them was again limited. The reasons for this are not totally clear. Preparedness, support and awareness of convoying merchant shipping were Jacking. United States implementation of the convoy tactic in the latter part of the War for merchant ship protection from the again successful U-boats in 1941-42 was not swift. Consideration of the period between the close of World War I and the beginning of World War II may provide some insight.

Editor’s Note: Part II will appear in the April 1999 issue of THE SUBMARINE REVIEW.