Thread: The Last Throw!

The campaign which opened on I February 1917 was fought with unparalleled ferocity. Three days later the United States broke off diplomatic relations, but did nothing more; losses soared from 368,000 tons to 540,000 tons by the end of February. The following month they reached 594,000 tons, just short of the figure of 600,000 tons, the level at which it was calculated that victory would be won.
The distribution of U-Boats on I February concentrated nearly all of them in the North Sea, 43 operating from German ports, 23 in Flanders, 23 in the Adriatic, the three still left in the Black Sea, and ten operational boats kept in the Baltic to counter the British and Russian submarines. (Figures vary, but those compiled by Grant in 1914-1918 have been used.)
Eight of the Baltic U-Boats were earmarked for the North Sea, and soon joined their sisters; work on the UB-Boats and UC-Boats was pushed forward with utmost speed.
New orders for the campaign had been issued on 17 January. The most important change was the insistence on using the English Channel route to save time, although it was permitted to retain sufficient reserve of fuel to allow a return via Scotland if the boat was damaged. It was suggested too, that boats forced to use the northern route should let themselves be seen, to mislead the British patrols into believing that the Channel route was blocked. When passing through the Channel U-Boats were to travel on the surface at night, preferably when the weather was bad, and to assist them in choosing the best nights Radio Bruges would broadcast weather reports. If sighted by a patrol the U-Boat would dive immediately and go down to 40 metres to avoid nets. Information about Allied minefields was given, with the interesting observation that British mines were usually laid close to the surface, and rarely exploded because of a badly designed firing lever. Despite this damning verdict 17 U-Boats were lost to British mines and mine-nets in 1917, and they were told to avoid minefields by diving to 20 or 30 metres. By this time it was known that Allied patrol craft were using directional hydrophones to track submerged U-Boats, and if any of these craft were encountered the U-Boat was to dive deep, stop all auxiliary machinery, and run quietly on one electric motor. To confuse the hydrophone operator the U-Boat would also stop from time to time to make a drastic change of course. It was also recommended that enemy submarines should be left alone, as torpedoes were needed to sink merchant ships.
An important innovation was the assignment of U-Boats to specific patrol areas whereas individual commanders had previously been given a free hand to choose areas likely to yield results. This was partly an inevitable tendency towards central direction, the only way in which the desired 600,000 tons per month average could be reached, but it also reflected the dilution of the experienced commanders with new and rapidly trained young COs.
A typical operational cycle for U-Boats included five boats: one operating west of the English Channel ('on station'), one heading west to relieve her, a third returning home from a patrol, a fourth docked for repairs, and the fifth completing her refit. This explains why the whole strength could never be available at any one time; in theory the cycle could have been suspended to allow a massive concentration, but in practice the steady rotation of U-Boats maintained a relentless pressure which yielded far better results and kept the enemy's forces at full stretch. The biggest problem was the time spent in transit, and when the U-Boats began to seek targets 200 miles west of Fastnet it became necessary to extend the cycle to include seven boats. Each ocean patrol lasted an average of 25 days, and the Dover Straits route saved six days of the total for a U-Boat from Wilhelmshaven. The Flanders U-Boats, being smaller, carried out 14-day patrols, and using the Straits saved them eight days.

A variety of weapons were hurriedly produced by the Allies. These two bomb-throwers (below) could hurl a stick-bomb weighing 200 Ibs several hundred yards, but they were only useful against U-Boats on the surface or just after they had submerged.

The U-Boats were pressing home the attack, and this led to a much higher loss-rate than before. Only 14 boats had been lost to antisubmarine measures and accidents in 1916, but no fewer than 11 were lost in the first four months of 1917. Four were sunk by gunfire from Q-ships; two were UC-Boats blown up on their own mines; one was torpedoed by a British submarine and one was sunk by a mine. One, U.76, was rammed by a trawler and then foundered in a storm; UC.46 and UC.39 were both sunk by destroyers, one by ramming and the other by depth-charging.
For the Allies the losses were now horrifying.
What had been an ulcer steadily draining their strength, had now become an open vein. Naturally the unrestricted campaign had not come as a surprise, and as early as October 1916 the Commander-in-Chief of the British Grand Fleet, Admiral Jellicoe, had warned the Admiralty that supplies of food and other necessities would be reduced to such a level that the British government could be forced to sue for peace by the summer of 1917. On 22 November Jellicoe relinquished command of the Grand Fleet to become First Sea Lord, and at the same time a special Anti-Submarine Division of the Naval Staff was created. This division produced a paper on policy for 1917, but it simply reinforced the existing countermeasures: hunting groups of warships and auxiliary patrols, minefields across U-Boat routes, and submarines to lie in wait for U-Boats in transit or to escort shipping. Jellicoe's advice had included a warning that new methods had to be found, but the Admiralty seemed unable to think of any new measures, and told the government that no answer was likely to be found to the U-Boat menace.

There could be no doubt that the existing methods were not working. The hundreds of auxiliary patrol vessels and warships could do nothing but scurry from sinking to sinking, arriving in time to pick up survivors but never in time to even catch sight of the U-Boat. The only inconvenience caused to the U-Boats was to force them to operate further out in the Atlantic, and as we have seen, this imposed a slight burden on the operating cycle, but did nothing to make U-Boats less effective. In fact the 'exchange rate' rose from 53 merchantmen to one U-Boat in February to 74 in March, and then to 167 in April.
The United States government had watched the slaughter of shipping with growing anger and finally on 3 April President Wilson told Congress:
“Civilisation itself seems in the balance, but right is more precious than peace, and we shall fight for the thing which we carry nearest to our hearts, for democracy, for the right of those who submit to authority to have a voice in their own government, for the rights and liberties of small nations, for the universal domination of right, for such a concert of free peoples as will bring peace and safety to all nations and make the world itself at least free”
There were many factors behind this decision some selfish, some practical but at the bottom of it was a final revulsion at the obtuseness of German diplomacy which had made very few concessions to neutral feelings. The mailed fist had been proclaimed too loud and too often as the arbiter of German claims, and British diplomacy had cunningly played on this insensitivity to libertarian sentiments. The use of Q-Ships, for example, had put the U-Boats in the position of having to attack without warning: the use of neutral flags, although historically regarded as a legitimate ruse de guerre for unarmed merchantmen, tempted U-Boat commanders to treat all neutral ships as Allied ships in disguise. But what could not be blamed on the Allies was the occasional exam pie of the practice of spurlos versenkt, or “sunk without trace”. One or two U-Boat commanders took the view that a sinking of an unauthorised category of merchantman could not be attributed to a U-Boat if there were no survivors. The most notorious instance of this was the sinking of the Hospital ship Llandovery Castle, which was returning empty from Halifax. On the night of 27 June 1917 she was hit by a torpedo fired by U.86 (K/Lt Patzig) over 100 miles west of Fastnet, and sank within ten minutes. For some reason the U-Boat surfaced, and Patzig demanded to know if a party of American airmen had been on board. The master, Captain Sylvester, denied having US military personnel among his crew, and indicated that he had been carrying seven Canadian military doctors. The U-Boat then began to circle at speed, and fired 12 shells at some unseen target; only the master's boat was ever seen again and the evidence indicates that the remaining 234 survivors, including nurses, doctors and crew-members, were killed by gunfire from U.86, after which the boats were sunk. Patzig and his two lieutenants were listed by the Allies as war criminals, and the junior officers were indicted at Leipzig in 1921, but Patzig had to be tried in his absence. The evidence of the helmsman indicated that Patzig had been stalking the brightly-lit hospital ship for four hours, and had been begged to spare her; Lieutenants Boldt and Dittmar were sentenced to four years' imprisonment.
Genuine atrocities like this were fortunately rare, but the fact remains that unrestricted submarine warfare aroused deep repugnance in most people's minds. After all, for centuries sailors have regarded the sea as the ultimate enemy of all sailors, and by torpedoing a merchantman in the Atlantic a U-Boat captain handed his fellow-mariners over to the common enemy. The hallowed tradition of making every attempt to save life at sea, even that of your enemy, had to be disregarded for all the reasons already stated, although right to the end of the war there were chivalrous U-Boat captains who, if they were not at risk themselves, would provide survivors in open boats with a compass and provisions. The debris of U-Boat warfare was in its way as grisly as land-warfare on the Western Front, and accounts of the period speak of ships ploughing through waters strewn with corpses, dead mules and splintered boats.
The furtive nature of submarine warfare made it seem underhand and unfair, and so the dangers and discomfort of the U-Boats crews were ignored. The U-Boats were uncomfortable at the best of times, and in winter the living conditions were barely tolerable. Condensation of moisture inside the pressure hull made tuberculosis an occupational hazard, but it also made bread go mouldy and dry clothing was a rare luxury. Recently documentary film of an inspection of U-Boats in 1917 has been rediscovered, and the first impression on seeing a mechanic coming up through the after hatch of the U-Boat is of a Negro wearing a black uniform, but he is merely covered in grease from head to foot. The hysterical language of propaganda on both sides did nothing to help. To cite only one example: after the Baralong incident British newspapers tried to make out that the four German sailors from U.27 had been lynched by irate American sailors from the Nicosian, incensed at the sinking of their ship; the German press reported that the boarding party of Royal Marines had thrown the four men alive into the boilers. In recent years the uproar over a book on the Lusitania incident has been a convincing demonstration of how long-lived the lies of wartime propaganda can be.

The depth-charge and its thrower, the first weapon capable of sinking a U-Boat after she had dived. The hydrostatic valve could be set to the depth at which the U-Boat was likely to be, and even a near-miss usually caused sufficient damage to force the U-Boat to the surface.

America's declaration of war on 5 April, not as an ally of Great Britain and France, but as an 'associated power' had a tremendous effect on the U-Boat war, but not immediately. For one thing the German military chiefs had allowed for it in their calculations, although their misreading of the American President's motives led them to expect intervention to be deferred for much longer. The US Naval Mission sent to London under Admiral W S Sims was dismayed to be told by Jellicoe that the U-Boats were winning. The neutral ship-owners had done what the U-Boats wanted them to do, by keeping their ships in port in the hope that American pressure would stop the campaign. Sims immediately responded by telling his superiors in Washington that massive assistance was needed, or there would be no war for the President to intervene in, and therefore no peace terms which he could dictate. As a stopgap six destroyers were sent over immediately to join the British escort forces in Queenstown (now Cobh) in the south of Ireland, but they could do little more than join the hunting groups which were frustrated participants in the deadly game of trying to catch U-Boats in the act of sinking ships. May, in fact, saw a slight drop in tonnage sunk, back to the March figure of just under 600,000 tons, but this was only caused by a reduction in the number of U-Boats at sea. The reason was the need to operate further west, already mentioned. The pace was a killing one, and although the U-Boat crews showed no sign of weakening in their resolve, their boats could not be repaired and refitted fast enough to get back to the maximum of 29 at sea in April (21 ocean-going boats and eight Flanders boats). May also saw the loss of six U-Boats in the Western Approaches and the North Sea, and the first fumbling efforts by the enemy to master a new countermeasure, the convoy.

Another method of using depth-charges was to roll them off the stern of a destroyer.

One may ask why this old and trusted method of protecting shipping, valid since the fourteenth century, had not been tried. The answer is that the British had thought about it, but had been persuaded rather too easily by both merchant seamen and their naval advisers that it was not practicable and would require too many warships as escorts. The escorts did exist but they were either tied up guarding the Grand Fleet or were frittered away in useless patrols around the British Isles. Merchant officers refused to believe that a group of ships could be handled together without colliding, and 'common sense' told them that their ship would be safer on its own than if it were tied to a group of other ships all steaming at the same speed. The weakness of the 'give us a gun and let us fight on our own' school of thought was that every merchantman had to make for one or more focal points where the trade-routes converged, and while making for these inescapable routes they became steadily more vulnerable to U-Boat attack.

Sliding a torpedo down the inclined loading hatch, into the forward messdeck. At this stage the weight is being taken by the depot ship's crane, but below it will be necessary to use sheer muscle power.

After the entry of the United States into the War the argument became less tenable. For one thing the US Navy could provide more escorts, and for another the bulk of the ships trading with Germany had been American, and when this traffic stopped most of the ships of the blockade squadron became available for convoy duty. Under pressure from the British Prime Minister, David Lloyd George, who had been convinced by his able Cabinet Secretary, Maurice Hankey, the Admiralty's objections were over-ruled. Oddly enough, the first ships to be convoyed were colliers taking coal across the Channel to France, and it had been done as early as February 1917 at the insistence of the were placed with American and Japanese ship-yards. A proper salvage organisation was built up and much more economical use was made of L shipping in a desperate attempt to cut the rate t, of attrition. Another long-overdue measure was to recall a number of good merchant ships L which had been extravagantly requisitioned by la the Royal Navy in 1914 as auxiliaries; they did c( little to reduce the efficiency of the Navy, and la were far more use carrying cargoes. The introduction of the convoy was thus only the final JI keystone in a radical rethinking of Allied policy if towards the U-Boats' war on commerce. The Allies were taking desperate countermeasures to save themselves from defeat, but the U-Boats themselves had not achieved the victory that they had hoped for. The combined diplomatic efforts of the United States and Great Britain wooed the neutrals back to the lucrative trade in and out of British ports, and by July the total of voyages by neutral traders was only 20 per cent less than normal. This meant that far more of the ships sunk by the U-Boats were neutrals, and so only 400,000 tons out of the 600,000 tons average were British ships. This meant that the campaign had sunk only 2.25 million tons of British shipping against the 3.50 million allowed for in the Naval Staff's calculations. Another factor not taken into account was the very human tendency of U-Boat commanders to over-estimate their victims' tonnages. As a result, this inflation of the figures masked the shortfall in tonnage sunk, and the Allies proved somehow to be able to last much longer than expected. What had certainly not been foreseen by the admirals was the flexibility of the world's shipping, first in reorganising its entire trading pattern to meet the emergency, and second, in making the convoy organisation work remarkably well.
The first effect of convoy on the U-Boats was to scour the oceans clear of targets. All the reports of U-Boat commanders from May onwards tell the same tale; instead of lying in wait until a target arrived, a U-Boat might wait days, and then be confronted by as many as 20 ships surrounded by destroyers. Any attempt to attack would invariably bring down a shower of depth-charges the dreaded wasserbomben, whose reverberating explosions smashed electric light bulbs and damaged the boat. The first convoy from Gibraltar to England arrived on 20 May without sustaining a single loss, and another followed from Hampton Roads shortly afterwards. An immediate reaction by the U-Boats was to attack the outward-bound ships, which at this early stage could not be given full escort. Even so, by October, only 24 ships out of 1500 had been sunk, and of these 14 had been sunk after leaving their convoy or through failing to keep convoy-discipline. The effect of even this partial convoying was to put an end to operations far out into the Atlantic, and by September very few ships were being sunk more than 50 miles away from Fastnet, whereas U-Boats had previously been able to pick off targets up to 300 miles out.

Four crewmen on the conning tower in varying states of cold and resignation.

There were other problems in store for the U-Boats. From September the British began to lay a new and deadly mine, the H2, which was a copy of the efficient German mine. These were laid in increasing numbers off the Flanders coast and in the Heligoland Bight, and between July and December 18 U-Boats succumbed to these minefields. The Royal Naval Air Service was able to escort convoys with large flying boats in coastal waters, and provided numbers of small non-rigged airships, the famous 'blimps'
These aircraft carried 100 Ib and 250 Ib bombs for use against surfaced U-Boats and a 230 Ib bomb with a delayed-action fuse to set it off 70 feet below the surface. The sight of a blimp or a 'Large America' flying boat over a convoy was usually enough to warn a U-Boat commander to keep out of the way, and so these air patrols achieved very few successes against the U-Boats in spite of their undoubted deterrent effect.
The convoy system has been blamed exclu¬sively by German historians for the frustration of the unrestricted campaign, and has been equally praised by the other side as the only thing which saved the Allies. But during the crucial six months from February to the end of July only about 350 large merchantmen were convoyed out of a total of some 3000 voyages. On the existing loss ratio this would have resulted in the loss of 35 if they had sailed independently, whereas only two of the 350 were sunk; this means that convoys only saved a possible 33 ships at a time when total casualties still approached 2000. Nevertheless in that time the exchange rate fell from 70 ships to 16 ships for each U-Boat sunk.