Yet another navy joined the forces at Gibraltar in the closing days of the war. Brazil declared war on Germany on 26 October 1917, and the Brazilians decided to send a naval force to European waters. They experienced considerable difficulty making the ships ready for sea, and the Brazilian squadron, two scout cruisers, four destroyers, and a tender under the command of a rear admiral, did not sail until the spring of 1918 and then experienced a long delay at Freetown because of illness among the crews. There was some debate over how the squadron would have been employed. The Italians wanted them in the Mediterranean, the Americans wanted them to work closely with U.S. forces, and the French wanted them to protect traffic from South America to Europe along the African coast between Dakar and Gibraltar. The Allied Naval Council appeared to favor the latter, but the long delay in their arrival at Gibraltar and the end of the war made the question academic.39
The international nature of Gibraltar was often reflected in the convoys. A British officer in the Flower-class sloop Lychnis described a 1918 convoy: “My most fantastic convoy from Genoa to Gibraltar consisted of my sloop as a fast escort (14½ knots!), a United States yacht, an Italian armed merchantman, a French trawler and a Portuguese trawler.”40 It would be naive to believe there were no problems; for example, an American officer in the gunboat Paducah recalled a squabble over responsibility for losses in a September 1918 convoy, but by Mediterranean standards things worked well. Moreover, the same officer emphasized how the attack in question came after Mediterranean submarines had become more wary and attacks and sinkings less numerous with things so quiet the last few months they thought nothing would happen.41 This in itself was evidence of the success of the Mediterranean convoy system.
Whatever the difficulties, the convoy system worked in practice, and this is best reflected in the decline in tonnage sunk by submarines. There were months when the sinkings rose over the previous month, but the overall trend was down. It is important to remember, however, that no one could know this at that time and the spurts in losses were alarming. Ships were far safer in convoys, but they were never immune to losses, and convoys sometimes had only minimal protection. And there remained traffic which was neither in convoy nor well protected. The coasts of Algeria and Tunisia were particularly vulnerable. The Mediterranean tonnage sunk in May 1917 fell to 170,626 tons—plus 10,270 tons sunk by the Austrians—compared to the record 254,911 tons sunk in April. The first Mediterranean convoys began in late May, and in June the tonnage sunk fell to 164,299 tons plus 6,174 tons sunk by the Austrians.
In June 1917 the Germans replaced the Mediterranean Flotilla commander, Kophamel, with a higher ranking officer, Kapitän zur See Püllen, who assumed the title Führer der Unterseeboote (F.d.U.) im Mittlemeer and the rank of commodore. During the month of June the Germans had 18 submarines either on operations or about to be put to sea. Nevertheless the tonnage sunk by Mediterranean U-boats declined again in July to 90,334, plus 16,969 tons sunk by the Austrians, and there was another decline in August to 79,549 plus 38,823 tons sunk by the Austrians. This would be the best month of the war for the Austrians, both in tonnage sunk and in comparison to their German ally. The Austrian sinkings were, however, erratic. They sank no tonnage the following month, 12,663 tons in October, 4,016 tons in November, nothing in December, and had their second best month of the war with 26,020 tons in January 1918. The Austrians had only a small number of submarines, and the inevitable intervals these boats had to spend in dock tended to distort the results of Austrian operations.
The eastern Mediterranean was another unprofitable diversion forced on the Admiralstab throughout most of 1917 by the army high command at the request of their Turkish allies, who faced the advance of the British army in Palestine. The pickings were generally slim, conditions unfavorable, and the boats would have been much better employed in other areas. There was a concentration of three to four U-boats off the Syrian coast in November, and UC.38 managed to sink the monitor M.15 and destroyer Staunch off Gaza, forcing the withdrawal of the British squadron that had been bombarding the port. However, the real thrust of Allenby’s offensive had been inland, and Gaza was captured, followed by Jerusalem a month later. The U-boats had been powerless to affect the course of the Palestine campaign, and the diversion to Syrian waters may have been responsible for the decline in tonnage sunk during November.42
The losses inflicted by the German U-boats jumped to 148,331 tons in December, the highest figure since the preceding June. The first through-Mediterranean convoys also suffered losses; OE.1 lost two ships and HE.1 lost three ships. It is not surprising that Calthorpe had doubts and feared that “this form of protection is not so efficacious as hitherto” and that convoys were a deterrent at best, not a reliable safeguard, and hampered in the Mediterranean by the restricted areas through which they had to pass. Calthorpe returned to the hoary old idea of making “offensive” operations primary, conducting the maximum effort in the Strait of Otranto and reducing numbers in the Aegean that were employed on minesweeping, blockade, and patrol. He also wanted to form hydrophone-equipped hunting flotillas in the Strait of Otranto. Calthorpe’s remarks were sufficient to touch off another debate over convoys at the Admiralty where, incredible as it may seem, more than six months after the introduction of the convoy system following that disastrous April, the director of Operations Division, Rear Admiral Hope, could still suggest they might make better use of destroyers by reducing the numbers employed on escort duty and using those released to hunt submarines, working by divisions, and possibly using hydrophones. Fortunately, by this time the champions of the convoy system, such as Captain Whitehead, the director of mercantile movements, had accumulated enough evidence outside of the Mediterranean to refute the proposals. Moreover, the four subsequent OE convoys had arrived at Port Said without loss.43
A careful analysis of the Mediterranean situation would have revealed that the problem was not so much the convoys but the scale of escorts with which the British and their Allies were able to supply them. It was one thing to have a convoy system on paper, but its value was greatly diminished when the scale of protection was minimal, say, one sloop and three armed trawlers for an OE convoy. The trawlers might not be able to maintain the speed of the convoy, and if they had to fall back to assist a damaged ship, they might have insufficient reserve of power to catch up again.44 Admiral Niblack estimated at the end of 1917 that there were only about two-thirds the number of ships necessary to furnish escorts for the convoys.45
Things were actually better for the Allies in the Mediterranean than they seemed, but this was hidden by what might be called the “fog of war.” The Admiralstab had discovered in September that in terms of tonnage sunk per U-boat day their success was declining. The situation did not improve for the Germans in 1918, although they substantially reinforced their Mediterranean U-boats at the end of 1917 and in early 1918 with ten of the new UB.III class. As of 1 January 1918, the Mediterranean flotillas were also divided in two with the First Mediterranean U-boat Flotilla at Pola and the Second Mediterranean U-boat Flotilla at Cattaro.
These reinforcements were offset by the increasing difficulties the Germans faced in maintaining their submarines far from home in Austrian bases. The problem was a shortage of skilled labor. In January 1918 there was a backlog of submarines awaiting repair and refit that numbered as high as 17 on one day in Pola and 14 at Cattaro. The German difficulties were compounded in the fall of 1917 by the increasing scale of Allied air attacks on both Pola and Cattaro. These problems only increased in the course of 1918. By June the commander of the German U-boat station in the Gulf of Cattaro reported that frequent British air raids, primarily by DH.4s operating from bases in southern Italy, were affecting the submarine war by interrupting and delaying repairs and refits on submarines and exhausting the crews.46
In early 1918 there was renewed danger convoy escorts would be weakened in order to strengthen the Otranto barrage. On 16 January Calthorpe proposed a major reorganization of the barrage.
The British commander in chief was seduced by the idea of bottling up the U-boats in the Adriatic and now wanted to deepen the barrage to cover sufficient depth from north to south so as to force submarines attempting to pass through the Strait to surface within sight or hearing of surface craft or aircraft. There would be new minefields, submarines on patrol north of the barrage, and kite balloon ships. Calthorpe envisaged lines of hunting craft equipped with hydrophones, which would force a submerged submarine to change course frequently, increase the distance it would have to travel, exhaust its battery, and thereby compel it to surface. The submarine would then be confronted by faster and more powerful craft than the trawlers and drifters the British had previously employed. Calthorpe proposed strengthening the destroyer force on the barrage, the destroyers to come from those on “defensive duties,” that is, escorts and patrols. In more specific terms, Calthorpe proposed substituting sloops for destroyers in escorting the OE and HE convoys at the price of delaying and weakening other convoys in the Mediterranean. Calthorpe, in effect, regarded the Otranto barrage as “offensive” and wanted to strengthen it at the expense of the “defensive” convoys. He also for utmost efficiency wanted the British senior naval officer at Otranto to command the barrage. This required agreement among the Allies and was discussed at a naval conference in Rome, 8–9 February.
The British gained their major point at the conference—a British senior naval officer for the barrage—but at the cost of having to agree to the French scheme of continuing the construction of a “fixed” barrage of mines and nets. The British, after their own design for a fixed barrage had been destroyed by bad weather, preferred a “mobile” barrage with destroyers and drifters. The French and Italians favored a fixed barrage, and the former were particularly dubious about the efficacy of hydrophones. The French and Italians both insisted, and the British finally agreed, that escorts should not be weakened until the barrage had proven itself. In the long run, this may have been the most beneficial result of the Rome conference, for it was some time before the barrage could be completed, and in the meantime convoys would not be weakened and might continue to prove their value.47
The Americans offered a partial solution to the problem of where to find more small craft for the Mediterranean. Two squadrons of “submarine chasers” were expected in European waters. The Allies had recommended that they be divided equally between the Mediterranean and the Atlantic, with the first squadron of 36 going to the Atlantic. The submarine chasers were 75-ton, 110-foot wooden-hulled craft, armed with a 3-inch gun and a small number of depth charges, and equipped with hydrophones. They were intended to work in groups of three or four, hunting for submarines with their listening devices. They were not, however, suited for escort work as they were too small and slow and could not keep up with even a slow convoy in any sort of sea. Furthermore, Admiral Benson and the Navy Department insisted they should be used “offensively” against submarines, and that meant hunting submarines, not other purposes. Calthorpe originally had wanted to use them on the Egyptian coast, but the Allies insisted they would be wasted here, and they were ordered to join the Otranto barrage.
The majority of the Mediterranean submarine chasers arrived at Corfu on 7 June under the command of Captain Charles P. (“Juggy”) Nelson. The tender Leonidas accompanied them. The chasers were nicknamed the “splinter fleet” and manned by enthusiastic amateurs, a large proportion college graduates or undergraduates. The Americans were confident their listening devices were far superior to those employed by the British and expected great things from them. They went out on their first hunt 12–16 June and when the war ended they had conducted 37 hunts. Nelson believed they had achieved no fewer than 19 “kills.” The truth is the chasers never achieved a single kill, and Admiral Sims at one point even admitted to a French officer that the Americans were using them “because we have them” although they were not very efficient for the purpose, because they had been designed before the difficulties of antisubmarine operations had been realized.48
The submarine chasers never fulfilled the hopes placed in them, but for that matter neither did the Otranto barrage. It accounted for only two confirmed kills in the course of the war, the Austrian U.6 caught in the nets in May 1916 and the German UB.53 mined in August 1918. The latter loss was due to the submarine commander’s not realizing the mine net had been extended and thus striking a mine while surfacing in the belief he was clear. Had he known of the extension, he might have avoided it. The barrage may have been responsible for the Austrian U.30 and the German UB.44, which disappeared without a trace, but even so, it would be scant return for the enormous efforts put into the undertaking.
There would have been even more effort had the war lasted longer. The Americans were engaged in the enormous Northern barrage mining project in the North Sea (see chapter 13) and had similar plans for the Mediterranean. The Americans expected to have a substantial number of minelayers available once the Northern barrage was completed and would also supply the majority of the material. A special Allied conference was held at Malta in early August with most of the discussions concentrating on the mining projects. The Allies recommended new projects off the Dardanelles, in the Aegean, and a second (Cape Cavallo–Saseno) Otranto barrage to be laid by the Americans. The Americans chose Bizerte as the site of their future minelaying base in the Mediterranean, but the war ended before any of these plans could be implemented.49
The submarine losses in the Mediterranean in the first half of 1918, although well below the peaks of 1917, remained high enough to cause alarm. The Germans, despite their difficulties with arranging refits, managed to keep an average 7 to 8 boats on operations all the time in January and an average 10 in March. The amount of tonnage sunk by the Mediterranean U-boat flotillas followed a seesaw pattern: 103,738 tons in January, 83,957 tons in February, 110,456 tons in March, 75,866 tons in April, 112,693 tons in May, and 58,248 tons in June. Sinkings by Austrian submarines remained erratic, from a high of 26,020 tons in January to nothing in February and June. The Allies might be said to have turned the corner after May 1918, for sinkings in the Mediterranean did not exceed 100,000 tons per month for the remainder of the war and showed a steady decline. The totals per month were: 76,629 tons in July; 65,377 tons in August; 35,856 tons in September; 28,007 tons in October; and 10,233 tons in November.
By the spring of 1918 the brunt of the U-boat war in the Mediterranean was carried on by the medium-sized boats of the UB.III class. The large U-boats that had been responsible for the outstanding successes of 1916 were not usually replaced if they were lost or returned to Germany for long refits. The Germans managed to keep up the number of U-boats; they still had twenty-eight in the Mediterranean in August. They also continued work on bombproof shelters at Pola, which could protect five submarines and would be finished by the spring of 1919. In August Commodore Grasshoff, one of the noted U-boat enthusiasts earlier in the war, became Befehlshaber der Unterseeboote (B.d.U.) im Mittelmeer.
The German submarines discovered that merchant ships were harder to find. The Allies developed an extensive network of direction-finding centers and stations in the Mediterranean. There were approximately 11 centers and 14 stations for the British, 20 stations for the Italians, and 14 stations for the French. Room 40 also sent a team of British cryptographers to Taranto, and later to Rome, in the spring of 1917. The Allies, as in northern waters, were therefore able to develop their ability to track U-boats and divert convoys and shipping away from danger areas.
The U-boats also found shipping much better defended, which was evident by U-boat losses. The Germans lost two U-boats in the Mediterranean in January, as many as in the entire year of 1917. Their worst month of the entire war came in May when they lost three U-boats and a fourth was heavily damaged and forced to take refuge in the Spanish port of Carthagena (where it was interned for the duration of the war).50 Another loss was UB.68, which lost trim and broke the surface while attacking a convoy southeast of Malta on 4 October and was sunk
by the gunfire of the sloop Snapdragon, trawler Cradosin, and steamer Queensland. The commander, Oberleutnant zur See Karl Dönitz, survived to become commander of German U-boats in the Second World War.51
The Allies were less successful in achieving unity of command for themselves. Consequently there was a substantial waste of capital ships employed watching the Austrian fleet because the French were unwilling to place their larger fleet under Italian command and the Italians would not consider anyone but an Italian C in C in the Adriatic. The British tried to get around the difficulty by suggesting Jellicoe as Mediterranean “admiralissimo,” but the project failed.52 Due to their inability to distribute assets rationally, and despite their paper superiority, for a time Allied naval supremacy in the Aegean actually seemed to be threatened. This was due to the fear—unfounded as it turned out—that the Germans would acquire control of the Russian Black Sea Fleet (see chapter 8). In the summer of 1918 Gauchet sent four semidreadnought Dantons to the Aegean to join the potentially outgunned semidreadnoughts Lord Nelson and Agamemnon. This superiority entitled the French commander, Vice Admiral Amet, to command of the combined squadron to the annoyance of the British.53
The French predominance in the Aegean was only temporary. Once Bulgaria was knocked out of the war in September and it seemed likely Turkey would soon follow, neither Lloyd George nor the First Sea Lord Wemyss could consider the prospect of a French admiral leading an Allied squadron into the Dardanelles. The Admiralty ordered Calthorpe to proceed to the Aegean and hoist his flag in a battleship. Shortly afterward they ordered the dreadnoughts Superb and Témeraire to Aegean waters. Wemyss estimated that counting auxiliaries, 75 percent of the warships in the Aegean would now be British, and they could logically claim command. The claim caused bitter words between the French and the British, including a sharp exchange between the French premier, Clemenceau, and Lloyd George. Calthorpe, with Austria also on the verge of dropping out of the war, stripped the Otranto barrage of 16 British destroyers followed by 24 trawlers, 5 divisions of drifters, and all usable motor launches and prepared to support an advance by the British forces at Salonika along the northern Aegean coast toward Constantinople.
A Naval History of World War I Page 69