[The Western Approaches is that part of the Atlantic Ocean extending out 300 to 400 miles from the southwestern and western coasts of the British Isles.]
Thus, from March to September 1915, the average number of modern U-boats on station every day was between seven and eight.
Pohl, who now commanded the High Seas Fleet submarine force, was not deterred. He intended to follow the plan recommended by Bauer. Three U-boats would operate on the Western Approaches and in the Irish Sea to interdict the main Atlantic trade routes to Liverpool and the Bristol Channel ports. One submarine would be stationed off the Thames in the English Channel, another off the Tyne, and still another off the northeast coast, covering the routes from Britain to Scandinavia. Six U-boats could not sink enough ships to halt British trade, but Pohl hoped that simply by making an appearance they would terrify merchant sailors, British and neutral. Pohl, however, was not allowed to begin the campaign without having a nervous hand placed on his sleeve. Before the U-boats sailed, the kaiser sent a telegram demanding a guarantee that within six weeks of the campaign’s opening “England would be forced to modify her attitude.” Tirpitz and Bachmann immediately responded that six weeks would be sufficient—“a silly question deserves a silly answer,” Tirpitz noted of this exchange. On February 14, Pohl, on board
Friedrich der Grosse,
was handed another imperial telegram: “For urgent political reasons, send orders by wireless to U-boats already dispatched for the present not to attack ships flying a neutral flag, unless recognized with certainty to be enemies.” Pohl was dismayed; if neutrals were promised immunity, there was no chance of frightening them away from trading with Britain. “This order makes success impossible as U-boats cannot determine the nationality of ships without exposing themselves to great danger,” he telegraphed the Naval Staff. “The reputation of the navy will, in my opinion, suffer tremendously if this undertaking, publicly announced and most hopefully regarded by the people, achieves no results. Please submit my views to H.M.” To this message, Pohl received no reply. Instead, the following day, still another telegram from Supreme Headquarters delayed the date fixed for the opening of the campaign: “H.M. the Emperor has commanded that the U-boat campaign to destroy commerce, as indicated in the announcement of February 4, is not to begin on February 18, but only when orders to do so are received from the All Highest.”
By February 18, newly clarified instructions had been issued to U-boats: hostile merchant ships were to be destroyed; all ships flying neutral flags were to be spared, although neutral flags or funnel markings alone were not to be regarded as sufficient guarantees of neutral nationality. To make certain, U-boat captains were ordered to take additional evidence into account: the structure, place of registration, course, and general behavior of the intercepted vessel. Hospital ships were to be spared, as well as ships belonging to the Belgian Relief Commission, funded in America to provide food for impoverished German-occupied Belgium. On the other hand, U-boat commanders were promised that “if, in spite of the exercise of great care, mistakes should be made,” they would not be held responsible. In this manner, says the official historian of the British blockade, “a handful of naval officers, most of them under thirty years of age, without political training, and isolated from the rest of the world by the nature of their duties, were . . . given a vague and indefinite instruction to give a thought to politics before they fired their torpedoes.”
British reaction to the announcement that German submarines were about to attack Allied merchant ships was divided: some felt that the threat was ominous; others said that the Germans were posturing and that there was little danger. Arthur Balfour, long an expert on defense, warned that the threat was real. On May 6, 1913, Balfour had written to Fisher: “The question that really troubles me is not whether
our
submarines could render the enemy’s position intolerable, but whether
their
submarines could render our position intolerable.” Fisher had replied by reiterating his credo: that “war has no amenities” and that as far as rules were concerned, “You might as well talk of humanizing hell!” Submarines, he pointed out, had no alternative but to sink their victims and thus were indeed “a truly terrible threat for British commerce. . . . It is freely acknowledged to be an altogether barbarous method of warfare . . . [but] the essence of war is violence and moderation in war is imbecility.” He added that neutral shipping could not be immune because “one flag is very like another seen against the light through a periscope.” Churchill, receiving a copy of Fisher’s paper, had pronounced it “brilliant,” but had noted, “There were a few points on which I am not convinced. . . . Of these, the greatest is the question of the use of submarines to sink merchant vessels. I do not believe this would ever be done by a civilized power.” Asquith and Prince Louis had agreed with Churchill. Even in February 1915, the Admiralty was generally satisfied that U-boats could not do much harm to Britain’s enormous merchant trade. Churchill, addressing the House of Commons on February 15 on the subject of the German war zone proclamation, declared that “losses will no doubt be incurred—of that I give full warning. But we believe that no vital injury can be done if our traders put to sea regularly. . . . If they take the precautions which are proper and legitimate, we expect the losses will be confined within manageable limits, even at the outset when the enemy must be expected to make his greatest effort to produce an impression.” The Foreign Office, for its part, doubted that the German government was sufficiently reckless to torpedo neutral—including American—merchant ships and concluded that the German proclamation was largely bluff.
In the end, the calculations and assumptions of both opposing belligerents—the German belief that the U-boats could terrify and drive away the neutrals, and the British estimate that the submarine war was bluff—were wrong. Bauer and Pohl had overestimated; neutral shipping did not flee in terror from the few submarines posted off British harbors. And, once the U-boats had sailed, it quickly became apparent that the diplomatic repercussions, warned of by Bethmann-Hollweg and discounted by Pohl, would be severe. On the other hand, over the years, the German submarine campaign, far from being a bluff, came close to winning the war.
On February 10, the U.S. government emphatically objected to the German proclamation of a war zone and warned that any harm befalling ships under the American flag, or American citizens—even if they were passengers on a belligerent vessel flying a belligerent flag—would be regarded in Washington as “an indefensible violation of neutral rights.” Specifically, the American note warned that “if the commanders of German vessels of war should . . . destroy on the high seas an American vessel, or the lives of American citizens . . . the government of the United States would . . . hold the Imperial Government to a strict accountability for such acts.” Italy, which was then at war with Austria but not with Germany, also spoke in strong language: if an Italian ship were sunk by a German U-boat, the Italian premier told the German ambassador, it would be
“une chose énorme.”
The unexpectedly stern language of the American protest note confronted the German chancellor with precisely the situation he had hoped to avoid. The United States was announcing that it had no intention of allowing itself to be frightened into giving up trade with Great Britain and was prepared to defend its right to freedom of maritime commerce. It was from this moment that German diplomacy toward the United States became an effort to mesh two ultimately incompatible policies: to continue to employ submarine warfare against merchant shipping while at the same time preventing America from joining the Allies. This first American note convinced Bethmann-Hollweg that he could combine these goals only by giving absolute guarantees that U-boats would not attack neutral ships. The naval command immediately protested that this limitation would make success impossible. Admiral Bachmann said flatly that if this undertaking to the Americans was given, the submarine campaign would have to be abandoned outright. Tirpitz bitterly reproached Bethmann-Hollweg for advocating any compliance with the American note. However, if, against his advice, concessions must be made, then, “in the interest of German prestige,” he demanded that they should come only in return for a lifting of the British blockade on all food and raw materials and the return of all interned German cargo vessels. Hearing this, Müller, who sided with the chancellor, wrote in his diary that Tirpitz’s ideas were “absolutely crazy.” Müller himself believed that “the effect of submarine war on commerce was greatly exaggerated” and agreed with Bethmann-Hollweg that the American protest note could be accepted without wholesale abandonment of the U-boat offensive. William II, caught in the middle, complained that Pohl had laid this weighty question before him at a time when his mind was on other things and admitted that his consent in Wilhelmshaven harbor might have been too lightly given. Ultimately, the kaiser endorsed the chancellor’s position. On February 18, on the eve of the beginning of the submarine campaign, Germany replied to the American note by saying that, while she insisted on her fundamental right to use submarine warfare against commerce and that her U-boat captains would sink British and Allied merchant ships, they would not molest American vessels, “when they are recognizable as such.”
In fact, German submarines were attacking Allied merchant shipping before the war-zone proclamation was issued. The first victim was the British freighter
Glitra,
866 tons, bound from Grangemouth to Stavanger, Norway, with a cargo of coal, oil, and iron plate. On October 20, 1914, she was halted by
U-17
fourteen miles off the Norwegian coast. A boarding party, acting in strict accordance with international law, gave the crew time to lower and enter their boats, then opened the
Glitra
’s sea cocks and sent her to the bottom.
U-17
then towed the lifeboats to within easy rowing distance of the coast. Seven days later,
U-24,
in the Channel to attack troopships, sighted the 4,590-ton French steamer
Amiral Ganteaume
off Cape Gris-Nez. The decks of the ship were crowded with figures whom the U-boat captain took to be soldiers; in fact, the vessel carried 2,500 Belgian civilian refugees. Without warning, the submarine fired a torpedo. Most of the passengers were taken off by a British steamer and the French ship, which did not sink, was towed into Boulogne, but forty people died as a result of panic. In November,
U-21
sank two small steamers,
Malachite,
718 tons, and
Primo,
1,366 tons, within sight of the French coast off Le Havre. Again, following the rules of prize law, the U-boat captain permitted the crews of both ships to enter their lifeboats before he sank the steamers with his deck gun. On January 30, a single U-boat,
U-21,
sank three merchant ships off Liverpool in a single afternoon. In each case, the sinkings were done under prize law rules. On February 1, the hospital ship
Asturias,
which the submarine captain genuinely mistook for a merchantman, was attacked off Le Havre but escaped. During the first six months of war—August 1914 through January 1915—ten Allied merchantmen totaling 20,000 tons had been sent to the bottom by U-boats, most of them in a gentlemanly manner and at trivial cost to the Germans who, not wishing to waste torpedoes, used bombs or shells from their deck guns.
Once the war-zone campaign began, the U-boat attack fell most heavily on the Western Approaches, through which most of Britain’s essential imports passed. This vital area could be reached only by the twenty diesel boats of High Seas Fleet flotillas, leaving the older, heavy-oil-engine boats to operate in the North Sea and the Channel. At first, U-boat captains attempted to discriminate in their attacks. British and French merchant ships were sunk on sight; neutrals were stopped, the ship’s papers were inspected, and, if contraband was found, the crew was allowed to take to its lifeboats and the ship was sunk by bombs or gunfire. In these cases, the papers were sent to a German prize court, which occasionally judged the neutral shipowner entitled to damages. Between February 22, when the campaign was launched, and March 28, German submarines sank twenty-five merchant ships. Sixteen of these were torpedoed without warning and fifty-two crew members were killed. Thirty-eight of these men died in a single attack, when a freighter carrying nitrates blew up. Nevertheless, on board the twenty-five ships sunk, not one passenger died and twenty of the twenty-five ships suffered no loss of life whatever. Meanwhile, every week, between 1,000 and 1,500 ships—more than 4,000 vessels a month—sailed in and out of British ports, a number that exceeded peacetime traffic in the summer of 1914.
At first, it seemed that there was little the Royal Navy could do to fight the U-boats. The Admiralty advised captains of British merchantmen to hoist neutral colors in the war zone, a questionable act that may have saved some vessels but also provoked a storm of protest from the neutral nations whose flags were flown. As for attacking the submarines themselves, no one knew how. Little thought had been given before the war to submarines as offensive weapons and even less to antisubmarine tactics or weaponry. The earliest British attempts to cope were primitive, even quixotic. Coastal yachts and motorboats patrolled outside British harbors, but only one in ten of these craft was armed with anything larger than a rifle. A few motor launches carried two swimmers, one armed with a black bag, the other with a hammer. If a periscope was sighted, the launch was to come as close as possible. The swimmers were to dive in and one man would attempt to place his black bag over the periscope; if he failed, the other would try to smash the glass with his hammer. Another unsuccessful scheme involved attempting to teach seagulls to defecate on periscopes. The most effective form of attack, ramming or gunfire, demanded that the submarine be caught on the surface. But as long as a submarine remained submerged, it was undetectable and invulnerable. Mines and minefields were laid down, but, being passive defenses, they had to wait for submarines to bump into them. Nevertheless, to protect the Channel from U-boats, twenty-two minefields with 7,154 mines were laid east of the Dover Strait between October and February. This mine barrier proved ineffective because British mines were of poor quality. They were visible on the surface at low tide and when struck they frequently failed to explode. Moreover, about 4,000 either sank to the bottom or drifted away. An effort to build a twenty-mile-long boom of heavy steel harbor-defense nets across the Channel from Folkestone to Cap Gris-Nez failed because the tides placed too great a strain on the mooring cables.