Before Convoys—Britain's Failed Anti-Submarine Warfare

by Dr. Jan Breemer

“We Are Losing the War”

On 10 April 1917 Rear-Admiral William Sowden Sims, U.S. Navy, sat across from the Royal Navy's Admiral of the Fleet Sir John Rushworth Jellicoe. Sims and his aide had arrived in London on that same day, less than  hours after their passenger steamer had docked in Liverpool. While they were at sea, on 6 April the American Congress had declared war on Germany and its allies. Anticipating hostilities, U.S. Navy Secretary Josephus Daniels had ordered Sims to London to, in Sims's own words, “get in touch with the British Admiralty, to study the naval situation and learn how we could best and most quickly cooperate in the naval war.” Now, sitting across from him—“calm, smiling and imperturbable”—was the First Sea Lord. With operational responsibility for the entire Royal Navy, Jellicoe was well placed to confirm the belief of Sims and most Americans that the British fleet “had the situation well in hand.” It did not. Sims was shocked to learn that the struggle against the U-boats had been far less successful than was being portrayed in the American and British newspapers. When he realized that the number of sinkings of British and neutral merchantmen was three and four times larger than reported, Sims observed, “It looks as though the Germans were winning the war.” Jellicoe agreed.

New, promising weapons, notably the depth charge, were being developed, but if the U-boats kept up their current pace of sinkings, they would not be ready in time. That was why it was critical that the U.S. Navy immediately send help in the way of destroyers and other small vessels. After his meeting, Sims cabled Washington that, “Briefly stated, I consider that at the present moment we are losing the war.” He also warned U.S. Navy Secretary Josephus Daniels that reports of British tactical successes against the U-boats should be treated with a great deal of skepticism. He wrote: “Do not accept reports of submarine losses as authentic and certain unless survivors are captured or the submarine itself definitely located by dragging.” [emphasis in the original]. The April report on monthly ship losses seemed to bear out Sims's fear. In what would turn out to be the peak month of the Uboats' productivity, 860,334 tons of shipping were sunk. Also, the exchange rate between the numbers of Allied ships lost versus U-boats sunk was, from the defender's perspective, the worst ever—167:1. 

The Royal Navy's failure, though, was not from lack of effort. Author and government adviser Henry Newbolt quite rightly labeled the U-boats’ “power to force unwieldy and disproportionate concentrations of ships” as “most extraordinary.” In his chronicle of the war at sea, he summarized the vast arsenal of ASW forces deployed in February 1917:  In February 1917 about two-thirds of our destroyer strength, and all our submarines, minesweepers and auxiliaries, were engaged in some branch of submarine warfare. . . In Home waters and the Mediterranean about three thousand destroyer and auxiliary patrol vessels were engaged in combating the submarine menace, either directly or indirectly; so that every German submarine was diverting some twenty-seven craft and their crews from other duties by pinning them to patrol areas and forcing them to spend their time in screening, searching and hunting operations which very rarely ended in success. 

The huge British anti-submarine defensive effort so far was clearly a shambles. Writing in his diary on 8 February 1917, Sir Maurice Hankey admitted that it looked like “our military effort would so far exhaust us that we cannot maintain our sea power and our economic position.” He consoled himself that his country seemed at least to be sinking “a good many submarines.” He was wrong. In February, the Germans lost five U-boats, four of which were due to enemy action. In March and April, another four boats fell victim to mines and other hostile causes. In other words, 1,104 ships were sunk at the cost of nine attackers! 

The Royal Navy's mainstay strategic scheme so far for giving in-and outbound-shipping at least a modicum of protection was rapidly unraveling. Involved here was the so-called “approach areas” strategy. This protective system had been introduced off the south coast of Ireland in the summer of 1915, but had gradually expanded to three “great cones of approach” in which oceanic shipping converged on Britain's ports. The scheme called for inbound shipping to be routed along very thinly patrolled approach routes until they arrived in home waters and could benefit from the more heavily patrolled inshore routes. Outbound shipping followed the reverse procedure. The system worked reasonably well while the U-boats operated relatively near shore; it fell apart when the larger boats sought their prey some 200 nautical miles farther west where patrol coverage was thin or non-existent and the approach routes converged toward the protected inshore lanes. These so-called “danger areas” of some 10,000 to 15,000 square miles quickly became death traps from which 25 out of every 100 steamers that left Britain in the spring of 1917 failed to return. As the minister of shipping wrote after the war, they had become the “graveyard of British shipping.” Even the Admiralty was compelled to admit at the end of March that, despite all efforts, the attack had outstripped the defense, with no solution in sight. The implication was obvious: “…the end of the war could be fixed with arithmetical precision at no very distant date.”

Captain Kenneth DeWar, RN

It's well known that it was the implementation of the convoy system reversed this dire situation. But, how did centuries of naval doctrine and the Admiralty bureaucracy get reversed?  It began with two forgotten Royal Navy Officers. One of Winston Churchill's most memorable phrases of World War II pays tribute to the young men who won the Battle of Britain and thereby arguably kept the country from German invasion. “Never in the field of human conflict,” the prime minister said on 20 August 1940, “was so much owed by so many to so few.” With only a slight exaggeration, the same might be said of two relatively junior Royal Navy officers who bucked the “system” to catalyze a counter-movement that halted the slide to seemingly inevitable defeat. Their names have become footnotes at best in most histories of the U-boat campaign, but had it not been for their willingness to question—at considerable risk to their careers—the prevailing assumptions and “facts” about the conduct of the anti-U-boat war, the “final solution” to the U-boat problem, i.e. the convoy system, might never have been adopted. 

The two were Commander (later Admiral Sir) Reginald Henderson and Captain (later Vice-Admiral) Kenneth G. B. DeWar. Both worked in the Admiralty—Henderson in the AntiSubmarine Division, DeWar in the Operations Division. It is not clear from the evidence which of the two took the initiative, the problem being, in part, that the accounts of their experience are curiously similar. In any event, between the two, it was discovered that (a) the attrition to British shipping was far greater than the public statistics suggested, and (b) the actual number of ocean-going ships arriving at and sailing from British ports was much smaller than was advertised, making the provision of convoy escorts a much more manageable undertaking than had been claimed by the Admiralty.

The successful implementation of the convoy system will be discussed in future articles at Roads to the Great War.

Source: Over the Top, August 2017