The Atlantic U-boat campaign of World War I

Issue OneNon-Fiction

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By Andy Goss

“There must be a beginning of any great matter, but the continuing unto the end until it be thoroughly finished yields the true glory.”

– Francis Drake

Trade, Conflict, and the Machines of War

The result of every conflict with external powers that Britain has engaged in over the past millennium has depended on the conduct of naval affairs. While the history of land warfare can largely be framed in terms of generals and battles, with only the occasional mention of technology and organisation, sea warfare consists for the most part of those two aspects. We see the occasional outstanding personality and a few memorable, though not always significant, incidents. Many books have been written about battles, such as The Glorious First of June, Trafalgar, or Jutland, and great commanders from Drake to Nelson. But advances, and mistakes, in naval architecture played a vital role in the failure of the Spanish Armada than any admiral, and over the centuries it has been the quality of ships and the seamanship of those who sailed them that plotted the course of history.

During the Nineteenth Century with the advent of iron and steam the picture begins to fragment. Increasingly, naval history is composed of ships, engines, guns, mines, torpedoes, and strange acronyms such as ASDIC, ASW, and RADAR. There have been great men, but only as great as their ships would allow.

Since Alfred the Great set about his naval building programme to counter the Vikings, and until the ascendency of air power in recent times, the warship has represented the nation’s highest technical achievement, the navy its most complex, most expensive organisation, and its naval personnel the most advanced in practically any technical area.

The contribution of sea power to the handling not just of conflicts, but of situations that may lead to conflict, lies in the control and protection of seaborne commerce. Britain, obliged by geographical necessity to conduct all international trade by sea, approached naval matters with greater consistency and attention than its continental rivals, leading to the almost accidental acquisition of a worldwide empire of unparalleled diversity.

Trade became the lifeblood of the nation, as well as generating profits through exports. Raw materials and food came in by sea. The ability to draw in resources from the ends of the earth was  the foundation of the wealth of the Victorian and Edwardian age, but it created a matching liability: trade routes and commercial relationships that had to be protected.

Britain entered the Twentieth Century with the largest and most powerful navy the world had ever seen, the 1889 Naval Defence Act stipulated that the Royal Navy should maintain a number of battleships at least equal to the combined strength of the next two largest navies. Despite some technical inferiority to the German fleet, during the First World War, the Kaiser’s War, the Royal Navy exerted effective dominance over the seas of the world, allowing trade to Britain and its allies to continue, while blockading Germany against seaborne supply.

That dominance, however, did not go unchallenged, a new, and thoroughly ungentlemanly weapon threatened to constrict the flow of trade. The submarine had arrived, and the German Navy, unable to make an impact on the surface, submarines being too slow to keep up with warships, used the new U-boat to strike, not at the British navy, but at its merchant marine homeward bound with supplies vital to the survival of the country and the prosecution of the war.

Marshalling merchant ships into convoys protected by warships was not a new technique, the Royal Navy had brought it to fine art during the Napoleonic wars a century earlier, but only in 1917 were convoys introduced to counter a renewed undersea onslaught, dramatically reducing merchant ship sinkings, while increasing U-boat losses.

The naval aspect of the First World War is inevitably overshadowed by the Western Front. The sheer loss of life tends to overwhelm the mind, can anything else matter beside that? Any event, however compelling, must be seen in context. The bloody stalemate of the trenches was a consequence of trying to fight old wars with new weapons, but the introduction of new technologies on land, under the sea, and in the air, prefigured wars yet to come, and a military paradigm that holds to this day.

The First World War saw the development of a number of technologies that affected the conduct of that conflict to varying extents, but have since become critical, even dominant, factors. It was the combination of barbed wire and the machine gun that ruined the orthodox doctrine of the day; fast mobile warfare, based on cavalry and field guns. Poison gas proved to be useful more as a threat than as a practical battlefield option. Telephony, both wired and wireless, played a part. Admirals, though, still seem to have preferred flag signals for naval use, in spite of the clouds of thick black smoke belching from their ships. In retrospect three new mechanical devices stand out: the tank, the aeroplane, and the submarine.

The tank, now ubiquitous, was still in its early stages at the Armistice. The aeroplane evolved rapidly from artillery spotting to both fighter and bomber roles. It was the submarine, though that had the greatest impact at the time, threatening to strangle British production of war materiel and starve the population, precisely the elements that drove Germany to negotiate the Armistice.

The necessity of providing some kind of defence against the U-boat drove the development of the floating mine, the depth charge, and early hydrophones. Mines, deployed in huge numbers, sank the most U-boats, almost twice as many as depth charges.

The Armistice, the Treaty of Versailles that followed, and the creation of the League of Nations were intended to end forever the prospect of a major war breaking out. All sane people agreed that the war just concluded had indeed been the War To End All Wars, as surely nobody could contemplate starting another such. How, just two decades on, the world found itself enmeshed in an even more destructive cataclysm, is a study in itself.

Economic Warfare

Napoleon’s dictum that an army marches on its stomach neatly encapsulates the logic of most of the conduct of wars over the past millennium. Supplies and supply lines dictate the possible for any military venture beyond the quick raid. Even low tech medieval armies needed resupply of military consumables such as arrows and horses. Food of course they stole as they went, which was fine as long as they kept moving, and there was anything left behind to steal.

Napoleon should have remembered what he had said when setting off for Russia. It was the impossibility of maintaining supply lines through the Russian winter, as much as the effect of the winter on his troops, that doomed the enterprise.

In an eerie, and tragic, echo of Napoleon’s megalomaniac career, Hitler, like Napoleon frustrated at his inability to break the British blockade of the coast of Europe, turned East.

In 1812, Napoleon’s army had to contend with long, difficult supply lines, deteriorating conditions, and a dogged resistance. In 1941 Hitler faced all that and a new factor, massive shipments of military equipment from the United States to the Soviet Union. It was the Arctic convoys that maintained that supply line, and the close blockade of Europe, that kept the Eastern Front in being and eventually overwhelmed the German war effort.

There are essentially two aspects to economic warfare, production and constriction. If a war goes beyond the initial strike, the sides must compete in production of war material and food, while harassing the other’s production. Any nation, or leader, and it is usually a leader or small clique, contemplating starting a war, needs to carefully audit the comparative capabilities of the probable combatants. Broadly speaking, assuming political will, and leaving aside any gross disparities in technology, the victor will be the side that out-manufactures the other.

During the Napoleonic wars, the Royal Navy established both blockade and convoy as foundation strategies. A close blockade of French ports inhibited international trade and made internal transport difficult. It also bottled up the French fleet, preventing it from gaining practical experience at sea, and depressing morale. In spite of the technical superiority of the French ships, when they did manage to slip out, they were defeated.

Convoys have been in use since at least the Anglo-Dutch wars of  the Seventeenth Century, but were adopted as routine by the Royal Navy during the protracted series of Napoleonic Wars, as the number of privateers roaming the approaches to the Channel made sailing unescorted extremely risky. As ever, the shortage of suitable escort vessels was acute, as all available resources had been devoted to building up the fleet of ships of the line of battle. Admiral Lord Nelson is quoted as saying “Were I to die at this moment, want of frigates would be found stamped on my heart.” Later commanders have echoed his feelings.

Blockade is the counterpart of convoy, and the Napoleonic Wars saw it applied by both sides. Napoleon attempted to destroy Britain’s economy through his Continental System, which made it difficult for neutral nations to trade with both France and Britain. The impact on Britain was severe, but the damage done to the economies of the neutrals, and to that of France, was worse, and the scheme failed.

Britain blockaded French ports, to suppress trade, and to keep the French fleet in harbour where it could not savage British convoys. The marathon effort of rotating enough ships to maintain the blockade in all weathers was hugely expensive, but largely successful, and brought the fleet up to a peak of competence that the French could not match.

This situation was mirrored during the First World War, with the difference that Imperial Germany was able to impose a counter blockade with the U-boat. However, this was not pursed consistently, and in 1916 U-boat operations were coordinated with the High Seas Fleet in unsuccessful attempts to lure the British Grand Fleet into a trap.

In 1917 the campaign of unrestricted attacks on merchant shipping was renewed in an attempt to end the war before the United States could fully mobilise. Sinkings rose dramatically, but in May 1917 when convoys were introduced sinkings dropped away and U-boat losses rose.

As had been the case a century earlier, there was a shortage of suitable escort vessels. Also some elements at the Admiralty were philosophically opposed to the convoy concept, leading to the removal of Admiral Jellicoe, the First Sea Lord.

Commerce raiding by surface vessels has a long history. The term “privateer” refers to the “private warrant” or “letter of marque” that gave legitimacy to ships preying on the enemy’s commerce. Privateers became increasingly common from the Middle Ages onward, a kind of Public Private Partnership navy that relieved the state of most of the cost. As commercial and naval architecture diverged, and European navies became larger and more competent, both privateers and pirates became outmoded. By the time of the First World War commerce raiding was conducted by purpose built naval vessels or heavily modified freighters, roaming the oceans and doing as much damage as possible before being caught.

The First World War ended when Imperial Germany ran out of resources, and the troops were on the verge of mutiny, indeed then High Seas Fleet did begin a mutiny, which was defused as the signing of the armistice changed the political landscape for ever.

The Kaiser’s War

The eruption of war in 1914 took Europe by surprise. The technical sophistication of the European powers made a shooting war almost unthinkable, particularly to those in a position to appreciate the destructive potential of the military machines built up since the previous major conflict. Whatever the causes of the war, nobody thought to ask the men who would have to go out and fight it.

The 1914 to 1918 war was called the Great War until another one, even worse, eventuated a generation later.  For a while it was referred to as the War to End All Wars, as indeed it should have been. But perhaps the best name for it is the Kaiser’s War, as without his insistence on military brinkmanship the sabre-rattling over the Balkans would probably not have involved the major world powers.

Britain, France, and Germany were well equipped for war, but unprepared. After a long period of relative peace navies, in particular, were geared to putting on a show. Polished brass and lustrous varnish were the top priorities, gunnery practice was not only expensive, but made the ship grubby. Britain had forced the pace with the Dreadnought battleship, but the emphasis was, as ever, on big gun glamour and not on overall fighting effectiveness.

Germany entered the war with twenty-nine U-boats, and had a run of successes torpedoing British naval units, which were unprepared for such attacks. Submarines were not liked by traditional big-ship naval men, who considered them underhand and ungentlemanly. Precautions, however, had to be taken. Barrages and mines were deployed, vulnerable ships assigned away from home waters, and zig-zag manoeuvres implemented.

Early in 1915 Germany launched unrestricted U-boat attacks against Allied shipping. The rules of war as they stood called for merchant ships to be allowed time for crew and passengers to take to the lifeboats before then ship was sunk. This was appropriate for a fast surface raider, but U-boats were little faster than many merchant ships, and carried fairly light guns, so surprise and the torpedo were to be employed. The complication was that only Allied, and not neutral, ships could be legally sunk without warning. Neutral vessels were, however sunk on several occasions, and the weight of protest began to build. There was particular concern that the United States might join the Allies, and after numerous American fatalities the campaign ended, and the U-boat fleet was ordered to coordinate with the High Seas Fleet.

Although technically excellent, the High Seas Fleet was smaller than the Grand Fleet. The German capital ships were good gun platforms, being wider than the British ships due to the maximum width of dry docks available. They were also well built, and had the advantage that they were built for local use, where the British ships had to be capable of operating away from port for months at a time. The German crews did not normally live on board, but in shore barracks.

As U-boats were much slower than the High Seas Fleet, the plan was for the U-boats to lie in wait while the High Seas Fleet lured the British Grand Fleet towards them. Caught between the hammer and the anvil, the result should have been a battle on traditional lines, ship against ship with little chance of escape until one side was victorious. Communications, however, proved difficult. Radio was in its infancy and although installed did not work as well as was needed. Combined with the difficulty of finding the enemy in the wilds of the North Sea, this prevented the two elements from ever working together.

By 1917 the war was not progressing well, German High Command was apprehensive that the United States would weigh in on the Allied side with enough industrial muscle and manpower to tip the balance. Consequently unrestricted attacks on merchant ships resumed, in full knowledge that this would precipitate American mobilisation, but, it was hoped, too late to prevent Allied defeat.

Over three months the U-boats doubled the tonnage they sank, to a level that if maintained was predicted to ensure victory in half a year. What had not been factored in was that Britain had yet to employ convoys, which the German military should have known to be highly effective. When ships began to sail in convoys in May 1917 sinkings fell dramatically, while at the same time U-boat losses mounted to three times the 1916 figure.

Anti-submarine warfare was primitive. There was no reliable way to detect a submerged submarine, and they were hard to sink, presenting small targets. Ramming was one of the more effective measures, if it failed to sink the U-boat it often caused it break off the attack and submerge.

The “cruiser rules”, and a preference for sinking by gunfire to conserve torpedoes provided a loophole. Q Ships, disguised warships or armed merchant ships, would wait for a U-boat to surface and then quickly run up the White Ensign and open fire. U-boats became warier, and took to sinking without warning, even though it used up precious torpedoes. By this stage nobody cared much any more for legality. European wars of the past had tended to end with the exchange of islands in the Mediterranean or Caribbean, but this time the stakes were higher, after four years and millions dead, war was no longer seen as glorious, and honour was stained with horror.

By November 1918, the war’s end, 360 U-boats had been built, and 178 lost. Allied sinkings had fallen to below 1916 levels. The future of the submarine was still uncertain, while it was acknowledged as a deadly threat, it was one that it seemed could be countered. The naval establishments may have felt that the challenge to the dominance of their bristling battleships had been met, and that the pre-war regime of spit, polish, and gold braid could safely be restored. Which it was, for a while.


Image: Willy Stöwer – Sinking of the Linda Blanche out of Liverpool