Episode 131: War Beneath the Waves Pt. 3

1917 Submarines Episodes

Last week saw the beginning of unrestricted submarine warfare for the Germans and throughout the first few months the campaign went quite well, with April 1917 being the best month of the entire war for the German submarines. However, no act, especially one involving hundreds of thousands of shipping tons being sent to the bottom of the ocean, goes without a response. This episode we will start by looking at what the British did to respond to the new U-Boat threat. This will then lead us into discussions about convoys and why it took the British so long to start using them. We will end this episode by talking briefly about the last 12 months of the war for the German U-boats, and unlike 1917 1918 would not be a happy time for the German sailors.

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Sinkings around Britain
Map of successful U-Boat attacks around Britain

Sinkings in the Med
Map of successful U-Boat attacks in the Mediterranean

U-Boat Deuschtland

German U-Boat
German U-Boat

Unrestricted Zone 1917
Area of unrestricted Submarine Warfare for 1917

American Newspaper
Newspaper from America


U-Boat War 1914-1918 by Edwyn A. Gray
A World Undone by G.J. Meyer
Ring of Steel by Alexander Watson
The First World War by John Keegan
Castles of Steel by Robert K. Massie
The Complexity of Strategy: Jackie Fisher and the Trouble with Submarines by Christopher Martin


Last week saw the beginning of unrestricted submarine warfare for the Germans and throughout the first few months the campaign went quite well, with April 1917 being the best month of the entire war for the German submarines. However, no act, especially one involving hundreds of thousands of shipping tons being sent to the bottom of the ocean, goes without a response. This episode we will start by looking at what the British did to respond to the new U-Boat threat. This will then lead us into discussions about convoys and why it took the British so long to start using them. We will end this episode by talking briefly about the last 12 months of the war for the German U-boats, and unlike 1917 1918 would not be a happy time for the German sailors.

One type of response from the British had nothing to do with stopping or slowing the pace of U-Boat attacks, instead it focused on reprisals. The Germans had made it very clear the hospital ships, even those clearly marked as such, would not have free reign in the English Channel. They did this because they believed that the British were using these ships to ferry troops, guns, and ammunition to the continent. They also claimed to have evidence of this fact after seeing khaki clad men on deck and they would go about repeating this fact to anybody who would listen. While the evidence may have been a bit dubious, the constant repetition by the Germans, and the other actions of the British up to this point in the war, meant that many neutral countries believed the Germans instead of the British. The British did not really care though, and the British would respond to these attacks not at sea but in the air, and I will let Edwyn Gray from his book U-boat War 1914-1918 explain "These wanton attacks brought forth various reprisals which showed, sadly, that the Allies were equally capable of terror tactics when aroused. On 14 April bombers raided Frieburg in the Black Forest in an attack that killed civilians ‘as a measure of reprisal’ and the French Navy began carrying German officer hostages aboard their hospital ships to prevent further attacks. Never loath to exploit terror the Germans responded by exposing triple the number of French officer prisoners in the firing-line on the Western Front. Apart from propaganda the reprisals achieved nothing and, after a while, both sides appear to have come to a tacit understanding and the tit-for-tat policies ceased."

Beyond the reprisals discussed above the British government responded to the U-Boat Attacks in three ways. First, through the Ministry of Food and Food Production Department they tried to reduce consumption and increase production on the home front. This basically meant doubling down on the policies that they had already been pursuing, at least since the Department was created under the Board of Agriculture in early 1917. The second policy was to make sure that neutral shipping was still available to them. Last week we discussed that one of the goals of the U-Boat campaign was to scare neutral shipping off of the seas due to the fear of the U-Boats and this did work. Countries like Norway, Denmark, and Sweden started to refuse to sail from British ports. But the British needed these ships on the seas and trading with British merchants and so they threw some of their muscle around. They essentially held neutral ships hostage and would not allow them to leave or return home until they were replaced by other vessels and their cargoes. If the countries continued to make much of a fuss the British threatened to use their blockade to prevent supplies from reaching the neutral countries at all, which they were already proving capable of doing. Basically, they were bullies. The third action that was taken was to begin pressuring the navy to enact convoys, which they did not do immediately.

Before we get to convoys, we have to take a look at the situation with the Royal Navy, specifically around destroyers. Destroyers are the biggest, strongest, or most glamorous of ships, but they served a crucial purpose. One of these purposes was to guard against submarine attacks. At this task the destroyers were the best that the British had to offer, with the ability to destroyer submarines on the surface, to dodge torpedoes with their speed and maneuverability, and later in the war to engage submarines with depth charges. Not every single destroyer had hydrophones or depth charges, but they were slowly being rolled out. The issue that the British had was that there simply were not enough destroyers. There were a total of 260 operational destroyers in the navy, but 100 of them were assigned to the Grand Fleet at Scapa Flow. The remaining 160 had to secure channel crossings, patrol the coast lines, and protect merchant shipping. Like any other ship they could not stay at sea indefinitely and much like the U-Boats a certain percentage would always be in port getting repairs and provisions. The final issue was that the destroyers were oil burning ships, but the fuel oil reserves in British were much lower than hoped, partially due to the U-Boats sinking so many tankers. The destroyers tasked with guarding merchant ships did the best they could, but there was a lot of ocean to cover, and a lot of ships on that ocean to protect. As with other events in 1917 the United States proved to be a great asset for the British. The United States navy had sent William Sims to London after war was declared to liaise with the Royal Navy. When he arrived he was greatly concerned about the submarine threat, but he knew that America could help. He cabled Washington and said that the best way to help the British immediately was to send any available destroyers to Europe to help guard the merchant vessels. He convinced those in Washington that it would be these destroyers that would keep the Allies in the war until the American army could arrive. He was told that 6 destroyers would be dispatched immediately, with more to follow. This may seem like a small measure, 6 destroyers is not much of a force, but it represented the tip of the iceberg and a huge difference in policy between the United States Army and Navy. Simms was a believer, and eventually the rest of the Navy was convinced, that the United States navy did not need to be an independent fleet in Europe, and instead it should just try to reinforce the Royal Navy. The British were, of course, a huge fan of this idea because it meant that the United States naval ships would work closely with, and be under the command of the Royal navy, for the entire war. While eventually that would mean a large force of vessels with the Grand Fleet for the moment it just meant that in the middle of 1917 American destroyers would be arriving in Britain and they would be put under the command of Admiral Sir Lewis Bayley, a British Admiral. By July there would be 37 destroyers under his command, with more to follow, and they would begin making a difference almost immediately.

One of the reasons that destroyers were so important was because of the ongoing discussion about the convoy system. Early in the war the Royal Navy hated the idea of convoys and much of their concern was around the fact that it meant putting so many eggs into one basket, and if a U-boat found the convoy they could wreak havoc. Admiral Jellicoe would write as much in his book The Submarine Peril "We frequently discussed the possibility of instituting a convoy system. We visualized the losses which might occur were an inadequately protected convoy successfully attacked and the prospects we had of providing sufficient protection to make the system reasonably safe." The convoys would also have to steam slowly, only as fast as the slowest ships, which would mean that many ships would spending more time in the danger zones than they had to by themselves. Even though the Navy would remain resistant to the idea of convoys the complete trouncing of merchant ships in April 1917 meant that they could not resist the calls for a convoy system. At the very least it had to be tried, and if it worked then great, if it did not work then it could be stopped and another solution found. On April 27th the Admiralty would give into the pressure and on that day an experimental convoy was setup that would sail from Gibraltar to the English Channel. There would be 16 merchant ships that would sail in 3 columns, and on the entire journey there would be two armed merchant ships and 3 armed yachts. Once the convoy was in known dangerous territory it would be joined by 6 destroyers. Simms, the American, would say that the goal of these destroyers would be to "establish a square mile of the surface of the ocean in which submarines could not operate and then move that square along until port was reached." On May 10th the ships left Gibraltar, on May 20th they entered Plymouth unharmed. The next test was for a trans-Atlantic convoy, which again was a success. By the end of the July there had been 21 convoys with a total of 354 ships that had crossed the Atlantic, with only 2 of those ships sunk by submarines. Karl Doenitz, later the commander of the Germany Navy in World War 2, would talk about part of the reason for this "The oceans at once became bare and empty. For long periods at a time, the U-boats, operating individually, would see nothing at all; and then suddenly up would loom a huge concourse of ships, thirty or fifty or more of them, surrounded by a strong escort of warships of all types." What became apparent quite quickly, to both sides, was that when the ships were in convoys it became incredibly difficult for the U-boats to find them. The Royal Navy had greatly overestimated the ability of the German U-Boats to find concentrated ships in the middle of the ocean. Winston Churchill would write that "The size of the sea is so vast that the difference between the size of a convoy and the size of a single ship shrinks in comparison almost to insignificance." By taking 20 ships and putting them in a convoy the Germans found it 20 times harder to find anything at all. Overall, the convoys would be incredibly successful, and they would begin the events that would see the effects of the U-Boats if not drop to nothing then at the very least reduce in impact to almost insignificance.

Even though the British were now making the right moves, the U-Boat danger did not go away immediately. To make sure they still had merchant ships moving forward they renewed their efforts to build more. As long as they could build ships faster than the Germans could sink them everything would be okay, and to do this merchant vessels were standardized and 35,000 skilled ship builders were recalled from the army. This was a good idea, because in June the U-Boats would score their second highest month at almost 700,000 tons. This would decline rapidly, with just 550,000 tons in July and 500,000 in August. During this time there was still a good amount of shipping that was sailing outside of convoys, and for these ships the lost rate was almost 14 times greater than those inside convoys. Another interesting fact about these months is that a large portion of the ships attacked by the U-Boats were actually hit on their way back to America after dropping off their cargoes in Europe. These ships would still be travelling completely alone until August. The U-Boats also tried changing up where they were doing most of their hunting. With convoys sailing over the open oceans the best chance to sink ships was around the British Isles, before the ships made it to their concentration points. Because of this change in hunting ground the number of ships sunk within 10 miles of the coast went from 20% of the total to almost 60% during the second half of 1917. For the rest of the year, the total numbers would fluctuate, but they would always be on a downward trend. 35,000, 450,000, 300,000, 414,000. Then for the first 5 months of 1918 they would average just 325,000. By the end of 1017 even if ships were still being sent to the bottom, the greatest threat was over.

During 1917 the U-Boats, while their raw results were decreasing also had issues in other areas. As the campaign drug on the politicians and public began to lose faith that the U-Boats could bring about the quick victory that had been promised. The German navy simply did not have an answer to what the British response had been to their submarine tactics. The American destroyers, which began to play a larger and larger role in covering the Western Approaches and as they were equipped with hydrophones and depth charges they became more and more efficient sub hunters. The convoy system had also made it almost impossible for them to even find the ships, let alone sink them and the protection offered by the destroyers began to cause irreparable harm to the U-Boat fleet. In the first half of the year, before convoys were introduced, only 20 U-Boats were sunk, however that numbers would balloon to 43 for the second half of the year. In 1918 it would get far worse. This caused the obvious problem of just not having as many U-boats on patrol, and it was impossible to increase production to compensate for greater losses, but the less obvious problem was the degradation of the crews. Up until late 1917 the Germans had always tried to staff new submarines with at least some veteran crew, to help bring the newer members of the crwe up to snuff. However, this would soon become impossible, with veteran petty officers a rare breed by the end of the year. This meant that what U-Boats could be manufactured were often manned by reserve crews with almost no experience and led by officers who were in much the same position. In early 1918 the grouping of submarines together was attempted, a tactics that would become much more famous in 1940, but by that point there simply were not enough U-Boats to both have these groups, or packs as they would be known, and also to cover all of the sea lanes which resulted in the groupings feeling counter-productive.

The Atlantic and North Seas were not the only areas that U-Boats were operating during the war. The submarines also operated in the Baltic and Black Seas along with their most profitable hunting ground, the Mediterranean. It would be here that over 660,000 tons of shipper was sunk during 1916. When the unrestricted campaign began in 1917 there would be a total of 27 German and 15 Austrian U-Boats in the area. One benefit that these boats had was the more constricted nature of the Mediterranean sea when compred to the more expansive Atlantic. This, when combined with the fact that the Med would always be a secondary theatre for the British meant that in April 1917 the British and French took the drastic step of routing a good percentage of the traffic that normally would have went through the Suez canal to instead go around the Cape of Africa, taking the increase in travel time to avoid the worst of the U-Boat killing grounds. One group of ships that could not leave the area completely were military vessels and in the Med they found life far more difficult than in other theaters. During the course of the first 3 years of the war 7 battleships were sunk, 3 French and 4 British. The tide did begin to turn after convoys were introduced, they were a natural fit for the more constricted sea lanes in the Med which already bunched ships up in certain areas. With the increased defense form destroyers the U-boats found life more difficult, but they continued to sink ships at a pretty good clip. That is not to say that the Germans did not have problems, beyond just the convoy system that would arrive late in the war. Their biggest issue revolved around logistics. The Germans and Austrians never imagined they would have so many U-Boats in the Mediterranean and they simply did not have the facilities to support them all. There were several instances where U-Boats had to sail the 4,000 miles back to Germany for more extensive overhauls, which took them out of the hunting grounds for extended periods. This was a problem that they would never solve during the war and it hit the Germans were it hurt the most, the number of U-Boats available.

As it would turn out, 1917 would be the most successful year for the U-Boats, by a pretty good margin, but the war did not end in 1917 and 1918 would be a different ballgame. They were still sinking ships, no doubt about that, 320,000 tons in February, 340,000 in March, 280,000 in April, 295,000 in May but it was now coming at great cost. 3 U-Boats were lost in February, 7 in March, 7 in April. They were also finding ships less frequently, thanks partially to the convoy system. In early 1917 the U-Boats had found and sunk a ship every 2 days that they spent out on patrol, by mid-1918 that was up to 14 days. This was putting a greater and greater strain on the men and their machines with the Germans needing to keep more boats out longer to make up for losses and reduced productivity. They needed more boats, but that was not going to happen fast enough. No matter how long they stayed out, no matter how many ships they sank, the truth way that by April 1918 it did not matter. The American and British shipyards were outbuilding what was lost by a good margin and even if the Germans could have double, tripled, quadrupled their U-Boats it may not have mattered, even if they were able to find men to crew them. In January 1918 the Navy had to move away from its volunteer system since it simply could not handle the number of crews that were needed, instead for the rest of the war men would be drafted into U-Boat service. Edwyn Gray describes the outlook of Admiral Scheer in mid-1918 "Even Scheer was showing signs of despair by now. ‘Many a U-boat with a splendid and experienced crew did not return,’ he lamented in his memoirs. ‘The results of the last months had shown that the successes of individual boats had steadily decreased.’ The lure of victory which had continued to burn bright in his eyes even in these final desperate weeks was, at last, growing dim. Lowering his sights to the realities of the situation he no longer sought victory, only ‘a tolerable peace.’" While the leaders and many within the submarine service were determined to continue fighting, on October 20th they lost their Belgian ports which they had used for U-Boat operations, making everything more difficult. Back in Berlin the feelings of the civilian government were at a breaking point, it was clear now that the situation was deteriorating out of control. On October 21 the U-Boats were informed that they were no longer allowed to attack passenger ships. It was hoped that this would help the new German government to gain favor with the Americans. What had started as a campaign with high hopes for ending the war quickly ended with a whimper.

A more immediately danger awaited the German Navy. By October 1918 all of the main fleet bases were taken over by mutineers and revolutionaries. We will dive into this more in later episodes, but at a basic level the men of the German Navy had decided they were done with the war and they wanted it to end so they revolted. They setup sailor and soldier councils in the ports and took control. Commodore Michelson, in charge of the U-Boats in the German ports gathered up every submarine he could and sailed out to sea with them. They hoped to find a place to go that was unaffected by the revolutionaries that now controlled the ports, but they would search in vain. A similar fate awated the U-Boats that were coming out of the Mediterranean. On October 20th the Ottoman Empire surrendered, which meant that the 4 U-Boats in Constantinople at the time had to find a new home. They refueled and began to make their way back to Germany. In this voyage they were joined by other U-Boats who were also trying to make their way back home from their Austrian ports, through Gibraltar, and back home. There were many smaller U-Boats which had to be scuttled because they did not have the range but 13 managed to make it out into the Atlantic. After their long voyage home, a lengthy and dangerous one, they arrived to find the naval bases fully under the control of the revolutionaries. Gustav Siess, a senior officer aboard one of the Mediterranean boats would recall that "The red flag of revolution floated over Kiel. Mutiny reigned aboard the ships in harbour and the red flag flew from mastheads. [But] the thirteen U-boats of the Cattaro base came into harbour in war formation [and] with war flags fluttering in the breeze." When the war was over the U-Boats were not in an ambiguous position, the British, French, and Americans wanted them and they wanted them destroyed. Every U-Boast that could put to sea was ordered to report to Harwich England, the first arriving on November 20th, all flying the flag of surrender. For the moment, the U-Boat threat was no more.

In total over 5,000 men would lose their lives with serving on U-Boats. Most of these were on the 178 German U-Boats that were destroyed either by enemy action or in accidents. 122 U-Boats would survive to surrender to the British in late 1918. In total they had sunk somewhere between 12 and 13 million tons of shipping, an impressive number that also came with a human cost, with 15,000 sailors and passengers killed on the ships. Regardless of how much damage the U-Boats did, in the end it did not matter. They had one goal, one purpose, and they had failed at it. They had been put to sea with the goal of cutting the British Isles off from trade, to strangle the country into submission. While millions of tons of shipping were sunk, this was not achieved. Because of this failure it is completely valid to question the decision to send them on their unrestricted campaign in the first place, in my mind I have come to the conclusion that it did not really matter either way. The U-Boats were not the only reason that the United States entered the war, while it may have been a catalyst at the moment, it is likely that they would have entered anyway. It did not make the situation in Germany any worse, people were already starving in the streets, and in fact in the short term it gave a big boost to morale on the German home front, something that was desperately needed. The Germans were optimistic about the ability of the U-Boats to accomplish their goal, so they took a chance and rolled the dice, it just happened to come up snake eyes. But if at first you don't succeed, try try again, and the Germans would indeed try again 20 years later, only to fail once more.