The British could expect some help from the Americans and would have had much more had the war not ended when it did. The strength of the U.S. Naval Air Service in European waters steadily increased after the first small contingent of 7 pilots and 122 mechanics without any aircraft of their own arrived in France in June of 1917. By the time of the armistice, there were 2,500 officers and 22,000 men with more than 400 seaplanes and aircraft. The Americans took over Killingholme Air Station near the mouth of the Humber, established four seaplane bases and a kite balloon station in Ireland, as well as six seaplane stations, three dirigible stations, and two kite balloon stations in France, and another two seaplane stations in the Adriatic. They were working on a large assembly and repair base at Pauillac near Bordeaux when the war ended. Killingholme was probably the most important strategic location. Operations began in July 1918 and by September there were 1,900 men and 46 aircraft flying regular patrols over the North Sea.
The Planning Section of Admiral Sims’s staff decided to concentrate the principal American naval air effort in the Felixstowe-Dunkirk area.71 They also intended to attack enemy bases and formed the Northern Bombing Group, based near Calais and Dunkirk. The force of naval and Marine Corps aircraft was independent as far as administration and internal organization were concerned, but operated under the control of the vice admiral commanding the Dover Patrol. There were originally to be 12 squadrons, divided equally into a day wing and a night wing, but production difficulties in the supply of aircraft forced a reduction to 8, half marines. The Americans, in default of aircraft of their own, ordered Caproni bombers from Italy for night operations, but deliveries fell way behind schedule and the type turned out to be unsatisfactory. Deliveries of American manufactured DH.4s also lagged, and they were forced to obtain DH.9a’s from the British. Operations did not really begin until the late summer of 1918, and when the war ended there were only 6 Capronis, 12 DH.4s, and 17 DH.9s out of a planned 40 Capronis and 72 DH.4s. The Northern Bombing Group made their objective the destruction of the submarine bases at Bruges, Zeebrugge, and Ostend, and there was a strong belief in the American navy that had the deliveries of aircraft equalled the readiness of the shore establishment and personnel the results might have been substantial. The American naval air effort was relatively small for much of 1918, but like so much of the American war effort, it seemed to snowball in the closing months of the war. It was yet another reinforcement to the antisubmarine campaign.72
The French contribution should not be forgotten either. The French naval air service grew from 8 aircraft and 32 pilots at the beginning of the war to 1,264 aircraft, 37 airships, 702 pilots, and 6,470 men at the time of the armistice. In a wide area from Dover to the Adriatic the French had 36 coastal bases, 6 centers for captive balloons, and 4 centers for dirigibles. Not surprisingly, much of the French effort was in the Mediterranean and Adriatic. The numbers at Dunkirk were relatively small, only three escadrilles or roughly 32 aircraft of different types in 1916. French seaplanes at Dunkirk suffered heavy losses in mid-1917, and the French clearly recognized that in the first half of the year German naval aircraft enjoyed air superiority. In September 1917 a German air raid virtually wiped out the French bomber escadrille at Dunkirk. The naval air war in the north was a predominantly British affair, but this was hardly surprising. The bulk of French naval forces operated in the Mediterranean and Adriatic, and the distribution of aircraft reflected this.73
The use of aircraft was severely limited by weather, and critics of aircraft could later point to lack of success in actually destroying submarines. A postwar technical study found that German submarines appear to have been surprised by the introduction of the “Large America” seaplanes in 1917, and consequently the new arm obtained excellent results. On the other hand, “the Germans progressed more rapidly both in appliances and tactics to avert attack from the air than we did in means for developing the attack.” In 1918 U-boats were generally fitted with “altiscopes,” which enabled them to check for aircraft in the vicinity before surfacing. The number of submarine sightings in 1918 increased over 1917, but not nearly in proportion to the increased number of hours flown.74 Kite balloons were also controversial, since they might divulge the location of a convoy and could usually be seen by a submarine before they themselves could see it.
It is certainly true that the aircraft employed on antisubmarine duties in the First World War had little ability to actually “kill” a submarine. But their greatest contribution was probably the respect they instilled in submarines and the limitations they therefore placed on submarine operations. When aircraft could provide aerial cover for a convoy, the convoy was virtually immune. It is hard to quantify the number of submarine attacks on a convoy that did not take place and the number of ships saved because a submarine was kept down by aircraft and prevented from obtaining a favorable firing position.75 In 1918 U-boats increasingly resorted to night attacks made on the surface. It has been estimated that toward the end of the war almost two-thirds of all attacks were made while surfaced at night. Coastal convoys reduced the effectiveness of the attacks in coastal waters. The aircraft coupled with coastal convoys had the effect of driving many German submarines out of coastal waters, and from May to July 1918 there was a sharp increase in the percentage of submarine attacks more than 50 miles from shore where the U-boat commanders hoped to be beyond the range of land-based aircraft. A post-World War II Admiralty study pointed out that the U-boats apparently preferred the difficulties of interception in the wider waters of the western approaches to the dangers of air attack inshore.76
Could the Germans defeat the convoys by a concentration of U-boats against them? We have seen that the Germans did not operate U-boats in concert the way they would in the “Wolf Pack” tactics of the Second World War (see chapter 11). They did attempt an apparent concentration against the convoy routes in the western approaches in May 1918, almost a year after the convoy system had begun. On 10 May the Germans had eight submarines in the danger area through which nine convoys had to pass. The Admiralty knew something of the concentration and diverted HG.73—an inbound Gibraltar convoy—to pass to the west of the positions of three U-boats. No attacks on convoys took place that day. The next evening U.86 sank the San Andres, one of a pair of ships detached from HG.73 for the Bristol Channel under escort of two trawlers. At dawn the following day, the U-boats suffered disasters. The huge liner Olympic, escorted by four American destroyers, was near the Scillies when she spotted U.103 on the surface. The Olympic’s captain promptly put his helm over and rammed and sank the submarine. Shortly afterward UB.72 was sunk in Lyme Bay by the British submarine D.4.
The U-boats had little luck over the next few days. They either missed the convoys completely or their attacks failed. On the 17th the skillful U.55 sank the Scholar (1,635 tons) in the well-protected Gibraltar convoy (HG.75), and shortly afterward the same boat sank the Denbigh Hall (4,943 tons) in the combined HL.33 and HJL.2 convoy despite efforts to divert the latter. Nevertheless, from 10 to 17 May the Germans, for a loss of two of their own, had managed to sink only three ships in convoy plus another two or three—there are minor inconsistencies between the text and detailed track charts—caught sailing independently. In that same period, 183 ships in inbound and 110 ships in outbound convoys had passed safely through the danger zone. The New Zealand Shipping Company’s Hurunui (10,644 tons) was sunk by U.94 48 miles south by west of the Lizard on the 18th. On 23 May the armed merchant cruiser Moldavia (9,500 tons) was torpedoed in the Channel off Beachy Head by UB.57 while escorting convoy HC.1. She was carrying American troops and 57–64—accounts vary—were lost. On the whole, however, German success remained small, and the apparent submarine concentration seemed to ease after the 25th.77 The British official history, published in 1931, was vague about British intelligence, merely remarking that “the Admiralty had roughly located” the U-boat concentration. We now know more detail on how wireless intercepts by the French and British assisted them to follow or antici
pate the movements of the U-boats.78
The Germans in 1918 also tried another variant in the U-boat war—the use of the large U-cruisers in waters far from the western approaches. The large submarines could undertake cruises of three months and included the merchant submarines of the Deutschland class, which had been converted for military operations. They were formed into the special U-Kreuzer-Verband. The unit’s ten large U-cruisers, plus approximately five older boats attached from time to time, operated in two distinct theaters. In the Eastern Atlantic the U-cruisers operated in the vicinity of the Azores, the Canaries, and the coast of West Africa. In the Western Atlantic they brought the submarine war to the shores of North America.
The operations of the U-cruisers in the Eastern Atlantic from December 1917 through May 1918 could not really be termed a success. Certainly the new U-cruisers, commanded by successful veterans including some of the most famous aces from the Mediterranean, sank ships. U.152 (Kapitänleutnant Kolbe) in a 117-day cruise sank 13 steamers and 4 sailing craft, or 30,580 tons; and U.155 (Korvettenkapitän Eckelmann)—the former merchant submarine Deutschland—in a 111-day cruise sank 10 steamers and 5 sailing craft, a total of 50,031 tons. The successes included the Italian naval oil carrier Sterope (9,500 tons), sunk after a one-hour artillery duel on 7 April, and the British troop transport Nirpura (7,640 tons) torpedoed in a Gibraltar to England convoy on 16 April. U.153 and U.154 operated together for a time and sank the British Q-ship Willow Branch (3,314 tons) after a hot fight off Cape Blanco on 25 April. But their success against shipping was meager. Furthermore, U.154 was torpedoed and sunk approximately 180 miles west of Cape St. Vincent by the British submarine E.35 on 11 May. The British had acted on an intercepted wireless message arranging a rendezvous with U.62 and had sent E.35 from Gibraltar. U.153 witnessed U.154’s destruction and was able to warn U.62.79 When U.153 returned to Germany after a cruise of 110 days, she had sunk only three steamers and one sailing craft, a total of 12,742 tons.
The score for the other U-cruisers was also unspectacular. U.156 in 117 days sank only 21,484 tons; U.157 in 135 days sank only 10,333 tons. U.156 had been lucky to return at all. She was nearly the victim of an elaborate trap sprung by Admiral Hall and British Intelligence. The British had intercepted a message arranging a rendezvous between U.156 and U.157 and a Spanish brigantine loaded with wolfram at Ferro Island in the Canaries on 17 January. The submarines were to bring the precious ore back to Germany. The British submarine E.48 was sent to the rendezvous and fired three torpedoes at U.156. One hit midships, but failed to explode.80
The submarine campaign was about sinking tonnage, and in the first half of 1918 a U-boat operating in the waters around the British Isles sank an average 280 tons per day, whereas the daily average for all the U-cruisers but U.155 had been below this. U.155 only just exceeded the average number of ships sunk per day, .15 to .13 in northern waters. In much of the same period, February to mid-April, no fewer than forty-two different convoys with 597 ships passed through a portion of the area where the U-cruisers were operating. Only one ship, the Nirpura, was sunk.81 The operations of the U-cruisers were not, in contemporary terms, cost effective.
Could an attack on shipping off the North American coast have had a greater effect—in a sense bring home the war to the American people? Could the convoys be defeated and the Atlantic bridge broken on the other side of the ocean? The onslaught by German U-boats on shipping off the American coast in the early part of 1942 certainly caught the U.S. Navy unprepared and the Germans took a heavy toll. This was not the case in the First World War. The Germans had certainly demonstrated they were capable of reaching North American waters during the period of American neutrality with the voyages of the Deutschland and U.53 in 1916, but the expected attacks had never materialized in 1917. The U-boats were obviously busy elsewhere. Sims had consistently advised Washington that regardless of what German submarines were capable of doing, or even if a few submarines reached the American coast, it would be a strategic mistake for the Germans to disperse their U-boat force for operations far from the critical area around the British Isles. A German submarine would have been able to make three or four patrols in the Eastern Atlantic for every patrol to North America and would find many more targets in the dense traffic of the shipping lanes around Britain and northern France. Sims was apprehensive that a few German submarines sent largely for propaganda purposes might arouse public opinion in the United States to the point where valuable antisubmarine craft would be retained in American waters rather than being sent to Europe where they were needed. He was confident they would have intelligence of German submarines departing for the Western Atlantic and would, if necessary, be able to divert antisubmarine forces from European waters, which would still arrive before the submarines.
The Americans were not to be deflected from the correct strategy. A special board appointed to study the defense of American waters took essentially the same line as Sims by recommending the dispatch of the maximum force to the active theater of the war while retaining a minimum force to parry a German offensive on the American coast. The special board and Admiral Benson, chief of naval operations, differed with Sims on an important point. Sims, reflecting the British viewpoint, believed American destroyers should be used to protect merchant traffic. Benson and the special board maintained priority should be given to the protection of American troop transports. Benson in February 1918 also opposed using American destroyers for screening duties with the Grand Fleet. They were to protect troop transports and mercantile traffic. Benson, reflecting his partiality toward protecting the buildup of American forces in France, also favored Brest rather than Queenstown as the primary port for American destroyers.82 Brest in 1917 lacked the facilities to serve as a major American naval base, and Sims had been content to send less than a dozen converted yachts for antisubmarine duties.83 In the face of the impending troop movements in 1918, the reluctant Sims was forced to divert forces to the French port, where Rear Admiral Henry B. Wilson became commander, U.S. naval forces in France, with his flag in the destroyer tender Prometheus. The Americans, characteristically, poured resources into Brest, constructing fuel tanks for example, and ultimately had more forces than at Queenstown when the major troop movements were taking place. There were no fewer than 36 destroyers, 12 armed yachts, and the usual complement of tenders, minesweepers, and tugs.84
These were not the only U.S. antisubmarine forces in northern European waters. There were also submarine chasers and submarines. Sub Chaser Detachment No. 1 (36 chasers and a tender) was at Plymouth and Sub Chaser Detachment No. 3 (about 30 chasers) at Queenstown. The submarines were 7 L class—given AL numbers to avoid confusion with the British L class—plus a tender and repair ship. They operated out of Berehaven on antisubmarine patrols.85
The question of whether to extend unrestricted submarine war to American waters produced considerable debate in Germany. By the spring of 1918, the converted merchant submarines of the Deutschland type were entering service along with the new large long-range U-cruisers. The arrival of these big boats was not without considerable technical difficulties, but now the Germans had the means to carry the war to the American coast. Holtzendorff in March 1918 proposed doing so in order to scatter the antisubmarine forces opposed to the Germans and because it was easier to interdict commercial traffic at well-known assembly points than at unknown destinations. Ludendorff and Hindenburg, anxious to stop the arrival of American troops, supported the move. The German Foreign Office was opposed, largely on the grounds it would inflame public opinion, bring neutrals into the war against Germany, and hamper possible peace negotiations on the basis of President Wilson’s Fourteen Points. The kaiser equivocated, first approving of the plan in April but then advocating postponement in June and July on the grounds that the Germans did not have enough submarines to make it effective. The kaiser stood firm against the military. Furthermore, Scheer was also against such operations in principle, and when he became head of the Seekriegsleitung in
August, the issue was not likely to be raised again. When German submarines began operating in American waters by the spring, they did so under the rules of cruiser warfare rather than unrestricted warfare.
There were some in the German navy who were not enthusiastic about any operations in American waters. Commodore Michelsen, Befehlshaber der U-Boote, was a leading example. He had opposed extending the prohibited zone to American waters after the large U-cruisers began to enter service. He considered the number of U-cruisers still too small, and, despite the success of U.53 off Nantucket in 1916, the time required for the long passage to and from their operational zone and for overhaul in the yard after each cruise would mean the large submarines would not be able to equal the tonnage sunk by smaller U-boats even though they would cost more to build and require more men to operate.86 In view of the lack of enthusiasm in the German government and navy—admittedly for different reasons—German submarine operations off the North American coast in 1918 were relatively limited in scope and less than what the Germans were capable of.
The first submarine to attack American waters, U.151, sailed from Kiel on 18 April and arrived off the American coast on 22 May. The submarine first laid mines off Chesapeake and Delaware bays, which claimed a 5,300-ton tanker (later salvaged) off Delaware. U.151 then proceeded to sink a trio of generally small coastal sailing ships north of Norfolk on the 25th and another six steamers and sailing vessels south of New York and about 60 miles off the New Jersey coast on 2 June. The largest had been the New York and Puerto Rico line’s Carolina (5,093 tons).
A Naval History of World War I Page 74