U-Boats, formidable and stealthy, played a pivotal role in reshaping the tides of World War I, forever altering naval warfare strategies and leaving an indelible mark on the annals of history.
Contributor Dan McEwen highlights the events of World War One.
Germany did not even have a navy when marine architects in its minuscule Coast Guard, while attempting to design a patrol boat with a really low waterline, ended up inventing the submarine. At least, that’s how they like to tell the story. Fact or fiction, at the outbreak of The Great War in 1914, the Imperial German Navy [IGN] was the undisputed global leader in ‘untersee-boot’ [U-boat] technology and tactics. Not that anyone noticed.
This was the golden age of sea power, when a fleet of battleships bristling with turrets of triple guns was the ultimate status symbol among European nations. You had to ante up a respectable blue water fleet just to get into the high-stakes game of colonialism. Germany’s Kaiser Wilhelm 2nd had triggered a minor naval arms race when he demanded a fleet of his own to keep up with his English cousin, George 5th and his Royal Navy. [Indeed, British and German sailors will be partying together after joint exercises when the war breaks out in 1914.] Unable to match the Brits’ Grand Fleet in quantity or quality, the Kaiser nevertheless steamed his shiny, new armada out on endless goodwill tours, proudly touting German naval prowess to potential allies.
All too aware of his fleet’s limits, its cautious commander, Admiral Karl Tirpitz hurriedly returned his precious warships to their home ports after every outing -– to the eternal disappointment of both the Royal Navy admirals and the IGN’s own captains who were more than willing to risk their ships and crews to go head-to-head with the Brits. Tirpitz knew better and kept them moored to their docks for the duration of the war, the Battle of Jutland  being the one notable exception. Thus by default, it fell to the submarines to do the heavy lifting for the IGN
In this task, they had an enormous advantage over surface ships: U-boats were much cheaper to build and operate! As many as 25 U-Boats could be built with the steel that went into a single battle cruiser like the Scharnhorst or the Gneisenau which sank exactly one ship each before being dispatched to the bottom of the South Atlantic by the Royal Navy! Then too, it took nearly a thousand men to operate a WW1 battleship, whereas even the largest U-boats required only a tenth that number. Smallest of all, the 2-man S-boats, packed a disproportionately huge punch, wreaking such havoc with shipping in the English Channel that an exasperated Royal Navy vainly resorted to ramming their pens in Zeebrugge in 1918!
An even greater threat came from UC-class subs which could lay mines faster than Royal Navy minesweepers could remove them. Torpedo-firing UC-boats based in Flanders terrorized the English Channel, their biggest kill being the cross-channel ferry Sussex with the loss of over 50 lives. The larger, 75-man UB model subs, still a modest 1,000 tons in size, sank nearly 12 million tons of shipping during the war. The IGN knew a good thing when they saw it. It began the war with just 38 U-Boats but over the next four years, 340 more would be launched.
At first, the Royal Navy didn’t know what to make of them. They weren’t even sure a sub could sink a warship until September 5th, 1914, when U-21 sank the cruiser-scout Pathfinder in broad daylight off the coast of Scotland in front of horrified crowds on the shore. Only 18 of the 268 crew on board survived. Two weeks later, U-9 torpedoed three albeit obsolete armored cruisers being used to train Royal Navy reservists. 1,459 of them went down with their ship. The sinkings left the admirals at Navy Command Headquarters in Portsmouth deeply shaken, believing as they did that the battle cruiser, backbone of their fleet, had just been rendered obsolete! [To be fair, the Royal Navy was a quick study and got into the submarine business too, although they favored bigger, faster vessels that could screen the surface battle fleets from German submarines. In this role, they are credited with killing 19 enemy U-boats.]
More than the airplane or the tank, “The submarine was the absolute weapon of World War One,” claims Dr. Jan Breemer, a submarine warfare expert at the US Naval War College. “Navies didn’t have any traditional responses for dealing with the submarine. Between 1914 and 1918, the allies deployed nearly 10,000 ships, thousands of planes, and laid more than 100,000 mines to combat the U-boat threat.” And therein lies the rub because, while subs were cheap to produce because they were lightly-armored, for that same reason they were easy prey for fast-moving warships armed with deck cannons and depth charges. Germany’s U-boat captains quite wisely chose to stalk safer targets, preferably slow, unarmed cargo ships.
Using their deck guns to force a ship to stop, a U-boat crew would allow the crew to escape in lifeboats before sinking it. Called ‘Prize Law’, or ‘Cruiser Warfare’ this practice had governed naval warfare for centuries. It meant that only a relatively small amount of shipping – 43,550 tonnes – had been sunk by these U-boats before Berlin’s first declaration of unrestricted submarine warfare in 1915. Still, Britons were particularly incensed by what they saw as “immoral” attacks on innocent civilian targets – unaware their government was plotting its own brand of treachery.
The Royal Navy began arming merchant ships, called ‘Q-ships’ which would fly the flag of another country in order to lure submarines in close enough for hidden guns to suddenly pop up and turn the tables. Winston Churchill, then First Lord of the Admiralty, proposed that captured German sub crews be treated as pirates to be shot on sight – in clear violation of the Geneva Convention!
Fatefully, that’s precisely how they were treated when on August 19th, the Q ship Baralong, a British cargo freighter flying a US flag encountered the US cargo ship Nicosian being boarded by the crew of U-27. Perhaps seeing another potential victim, the sub’s lookouts let the freighter approach. Only at the last minute did the Baralong switch flags to the British Red Ensign and reveal its deck guns. These quickly sank U-27 but that didn’t satisfy the Baralong crew and they machine-gunned the surviving crew as they swam for the Nicosian. Their blood still up, a squad of crewmen rowed over to the Nicosian, leapt onto the deck and shot the last survivors – to the absolute horror of the American sailors who’d just rescued them!
When, a month later another Q-ship repeated the same charade and bagged U-41, an outraged German Chancellor Bethmann-Hollweg condemned the illegal deceptions as “war crimes”. 14 U-boats fell prey to this ruse before the IGN retaliated on February 4th, 1915 by freeing their sub captains from Prize Law, its first attempt at unrestricted warfare. Shipping losses skyrocketed at the rate of nearly 100,000 tons per month, an average of 1.9 ships daily! The British Empire struck back.
Order-In-Council #155 initiated a naval blockage of all commerce to Germany and the neutral ports [i.e. Rotterdam and Antwerp, Holland] that served it. The German’s upped the ante by mining the Thames Estuary: the Royal Navy countered by declaring the entire North Sea a war zone and mined it all heavily. Its Grand Fleet then arrayed itself in a blockade of the North Sea from Scotland to Norway – well out of the range of German U-boats. Cargo ships bound for those neutral ports had to stop at Dover to obtain the Royal Navy’s navigation route through the mines. Its sailors would use this opportunity to “inspect” the ships for contraband, delaying them for up to a week before they were allowed to continue their voyage. The tactic quickly had the desired effect. For the major shipping companies who owned these vessels, time was money. Putting profit before politics, one by one the CEO’s of all the major shipping lines signed agreements not to carry materials to Germany – even when their home countries passed laws specifically prohibiting this!
Hardly surprising then, that by the end of 1915, the imports vital to feeding both Germany’s people and its war machine had fallen 55% from pre-war levels and the real misery hadn’t even started. Nagged by doubts that it could still achieve a decisive victory, Berlin put out feelers to London about declaring a truce, at least on the high seas. The IGN would end its unrestricted sub warfare if the Royal Navy would end its blockade. “Not bloody likely!” was the essence of London’s politely worded reply. Undeterred, the German diplomats went over their heads, to Washington. Anxious to end the threat to their own merchant fleet, the Wilson Administration agreed to lobby London to accept the proposed truce and drop Order #155. And then Walther Schwieger, Captain of U-20, saw a ship slowly emerge from a fog bank off the Irish coast and fired a single torpedo into the 700-foot long hull of Britain’s premier ocean liner.
The most infamous maritime disaster of the war, the Lusitania went down in 20 minutes taking with it 1,193 passengers, including 128 Americans. Rescuers pulled 761 survivors from the icy Atlantic but nothing could save Germany’s public image. Berlin insisted the ship was carrying weapons but to no avail. The volume and vehemence of the international outrage that followed stung Kaiser Wilhelm into putting the U-boats back on their leash. Days later he belatedly issued an apology. But on Main Street USA, “Sorry” didn’t excuse 128 American lives. Fuming, Washington nixed any lobbying on Germany’s behalf concerning Order #155 although tellingly, there was no Declaration of War. Despite public outrage at the sinking, President Woodrow Wilson remained determined to keep America out of the war, making it a campaign promise in the 1916 election. But at that moment it was Britain, not America, that preoccupied Germany military managers.
Even with Vladimir Lenin’s help, knocking Russia out of the war in 1917 had proved so costly to the Germany economy that Paul von Hindenburg, the military’s Commander-and-Chief, insisted in a memo to the Kaiser that; “Stronger measures have to be put into place to break England’s will.” Translation: put the U-boat fleet to sea to slow the flow of food and war materials pouring into Britain.
Unbeknownst to Hindenburg, Chancellor Bethmann-Hollweg had secretly approached the Allies about a truce, not just to end the sub warfare, but the war itself. The new governments in Versailles under George Clemenceau and in the Palace of Westminster under David Lloyd George, weren’t anymore interested than their predecessors and slammed the door. Again the Chancellor approached Washington and just as in 1915, he was assured it would back his initiative with London. Unlike 1915 however, American dollars were now bankrolling both the French and British war effort. Wall Street bankers and the US Treasury agreed to cut off the flow of money to both if they didn’t start talking. This promise was actually put on paper in a letter the hopeful Chancellor carried in his breast pocket when he set off on January 18th 1917 for a meeting with the Kaiser and his military advisors. A path to peace lay open; all the Kaiser had to do was take it. But the war didn’t end until 1918 because the meeting did not go well.
Bethmann-Hollweg arrived to find the generals and admirals had come up with a plan to beat the Brits at their own game. They’d brought with them a bespectacled economist named Dr. Richard Fuss. Director of a renowned German banking institution, Fuss had done the math and calculated that if the U-boats could sink 630,000 tons of shipping per month, Britain would be starved into suing for peace within six months. This would of course draw the United States into the war against them but, Fuss insisted the Brits would throw in the towel before the Americans could get mobilized! To Hindenberg and his gold-braided peers around that table, Fuss’s cold-blooded logic was irresistible. Why make peace if we can still win the war?
Bethmann-Hollweg on the other hand, was aghast that they were so willing to play; “…a game of roulette, in which we stake our existence as a great power…on a game in which odds supposed to be in our favour are not calculated odds, but mere speculation that Great Britain will be reduced by the autumn.” He was voted down and would soon be replaced. For the second time in the war, Germany would wage unrestricted submarine warfare. This decision is seen by many historians as Berlin’s worst decision of the war because just as Fuss had predicted, the inevitable happened.
The renewed attacks started in February and by March eight ships flying the Stars and Stripes had been sunk by German U-boats. For Americans already livid over the discovery of German Secretary of State Arthur Zimmerman’s secret initiative to inveigle Mexico into invading southern United States, the sinkings were the last straw. Congress overwhelmingly approved Wilson’s Declaration of War against Germany on April 2nd,,1917.
No more than 60 of the IGN’s total complement of 340 subs were ever on active patrol at any one time, and yet Allied cargo losses began to rise just as they had in 1915. February – 536,000 tons. March – 603,000. April – 875,000! Dr. Fuss’s plan was working like a charm! And then suddenly it wasn’t. What the banker’s calculations hadn’t anticipated was the Allies new secret weapon – convoys!
Beginning in May of 1917 onward to the end of the war, merchant ships to the UK traveled in convoys escorted by destroyers. This time it was Tirpitz and his admirals who had no response to this new tactic. Because their subs hunted alone – radio-equipped wolf-packs would be a WW2 innovation – they were forced to go looking for the convoys and once found, became the prey of the escorting destroyers. 72 German U-Boats would be lost to their attacks, making them the leading cause of death for IGN sub-crews. As the U-boats went down, the survival rate of the cargo ships went up. Monthly losses of just British shipping alone dropped precipitously from 550,000 tons in May 1917 to just 50,000 tons by November of 1918.
On the other hand, the British blockade remained unbroken. In 1937, Duff Cooper, First Lord of the Admiralty during the war, belatedly admitted that; “We did everything in our power to starve the women and children in Germany.” Before it was over, the “Hunger Blockade” would contribute to approximately 800,000 deaths, many that occurred in the months after the war. Sick, starving, grieving the loss of two million loved ones, fed-up waiting for a long-promised victory that wasn’t coming, the German people offered their leaders a stark choice: peace or revolution.
The Kaiser had hoped Tirpitz’s U-boats could do what Hindenburg’s armies couldn’t – decide the war. They did, but not how he or anyone else in Berlin expected. By bringing the world’s most powerful industrial nation into the war against them, their subs decided Germany’s fate.” – Dan McEwen
- The U-Boat Campaign and Experiences 1914-1918, Graham Kemp, Western Front Association lecture
- The Second World Wars, Water episode, Victor Davis Hanson, Hillsdale College online series
- Submarines and Submarine Warfare, Mark Karau, online essay
- How WW1’s U-Boats Launched the Age of Unrestricted Warfare, Wired magazine Sept. 2014
- A “Weapon of Starvation”: The Politics, Propaganda, and Morality of Britain’s Hunger Blockade of Germany, 1914-1919, Alyssa Cundy, PhD dissertation
- Notes on the Memorandum by Admiral von Holtzendorff Regarding Unrestricted U-boat Warfare, Dirk Steffen, online essay
The First World War, TV series, The Great War in Numbers, TV series, The Great War, TV series
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