Blackett's War (5 page)

In general, the law permitted a captor to burn or sink a prize and its cargo only if its enemy ownership was beyond doubt; even in that case, the captor had an unambiguous duty first to remove the crew and passengers and to preserve the ship’s papers and other documents for examination by a prize court to validate his action. The London Declaration of 1909, an agreement on the laws of naval war signed by all the major European powers and the United States, reiterated all of these points, in particular the rules respecting the rights of neutrals. Although never formally ratified, the London Declaration for the most part was simply a restatement of the existing admiralty court precedents that constituted the international law of naval war. Notably, while offering one exception to the rule that ships of neutral countries always had to be taken into port for “the determination of all questions concerning the validity of the capture”—Articles 49 and 50 permitted the destruction of neutral vessels that were otherwise subject to capture and condemnation in the case “of exceptional necessity,” if “the safety of the warship” or “the success of the operations in which she is engaged at the time” would be endangered—the declaration underscored the one inviolable principle: “Before the vessel is destroyed all persons on board must be placed in safety.”

Submarines could hardly take on board “all persons” from a freighter or
passenger liner before sinking her with gunfire or torpedoes; nor did they have men enough of their own to spare to place aboard a captured vessel as a prize crew; nor the armament to escort a prize to port and protect it from recapture along the way by an enemy warship.

But it was the grand strategic ideas of navy men of the early twentieth century that spoke loudest in relegating the submarine to a small, and largely defensive, supporting role. Mahan’s writings on sea power theory had been enormously influential in all major naval powers of the world, and if there was one sacred truth in the gospel according to Mahan, it was that navies existed to defeat an enemy’s navy. Concentrating one’s naval power in a single mighty fleet would force an enemy into a climactic fleet-on-fleet battle that would decisively secure control of the oceans for subsequent operations; meanwhile, the very threat posed by such a concentrated force would compel the enemy to concentrate his forces as well to avoid defeat in detail, thereby leaving his own coasts vulnerable and checking his ability to conduct smaller forays. Commerce raiding was, in this view, a fatal dispersion of effort, or at best an inglorious sideshow to the real action.

Certainly that was Germany’s conception in the years leading up to 1914. A British diplomat who visited Berlin before the war seeking a diplomatic end to the spiraling naval arms race between the two powers found the Kaiser a devotee of Mahan. Wilhelm II had read the American captain’s book
The Influence of Sea Power Upon History
and was convinced that German greatness depended on control of the seas. “Germany,” the Kaiser declared in 1900, “must possess a battle fleet of such strength that even for the most powerful naval adversary a war would involve such risks as to make that Power’s own supremacy doubtful.” Since launching its crash naval construction program in 1898, Germany had set more and more ambitious targets as it sought to challenge Britain’s supremacy, eventually reaching a mighty seagoing force of sixty battleships and battle cruisers. The German High Seas Fleet was conceived on pure Mahanian lines: a series of battle squadrons each built around a core of seven or eight of the huge ships attended by flotillas of light cruisers and destroyers. Winston Churchill, shortly after taking office in 1911 as first lord of the Admiralty—the top civilian minister of the navy—warned that the Germans were building a sea force designed for “attack and for fleet action,” not merely for the defense of Germany’s overseas colonies and trade. The Germans, he concluded, were preparing “for a great trial of strength.”
¹⁶

In 1901 Admiral Alfred von Tirpitz, the master architect of the rising
imperial fleet, had bluffly declared, “Germany has no need for submarines.”
¹⁷
It was only in 1906 that the German navy acquired a single submarine for evaluation purposes, the last of the major naval powers to do so.
U-1
—the “U” stood for
Unterseeboot, U-boot
for short—was workable if unremarkable in its design. The first German submarines were powered by noisy two-stroke kerosene engines that belched huge plumes of thick white smoke and showers of embers, making them visible from afar day or night. Tall vent stacks mounted on the deck had to be detached and stowed before the boat could dive.

By 1910 German designers and shipyards had started to catch up with their rivals. From
U-19
on, German submarines were equipped with quieter, safer, and more reliable diesel engines. These new boats were also substantially larger, oceangoing vessels, 210 feet long, with four torpedo tubes (two fore and two aft), carrying 100 tons of fuel, giving them a theoretical range of as much as 10,000 miles. But only ten of the diesel-electric U-boats had been completed when war began on August 1, 1914. Overall, Germany’s submarine fleet remained minuscule, numbering just twenty-four, a third as many as Great Britain’s.
¹⁸

Convinced that Britain’s Grand Fleet would immediately descend upon the Heligoland Bight for the climactic confrontation foreseen by Mahan’s theories, the German naval staff ordered all of its U-boats into a static defensive line with the start of the war. The U-boats were kept on the surface, moored to buoys, as part of a multilayered defense around the German naval base at Heligoland Island. The plan was for an outer ring of destroyers to launch torpedoes and then fall back, leading the enemy through the line of U-boats, which would submerge and launch their weapons; an inner ring of torpedo boats would then try to further harry and whittle down the enemy before the High Seas Fleet sallied forth to join the battle in earnest.
¹⁹

But the British confounded expectations by holding back: in place of the grand climactic battle came anticlimactic stalemate. As early as October 1914 the commander of the German submarine force, Fregattenkapitän Hermann Bauer, chafing at the absurdity of keeping the bulk of his boats tied up to buoys in a circle around Heligoland for a battle that might never come, was urging the potential of the U-boats to strike a devastating blow at British oceangoing commerce. The commander of the High Seas Fleet relayed Bauer’s arguments in a report to the chief of the naval staff, Admiral Hugo von Pohl: “I beg to point out that a campaign of U-boats against
commercial traffic on the British coasts will strike the enemy at his weakest spot, and will make it evident to him and his allies that his power at sea is insufficient to protect his imports.”
²⁰

Pohl demurred. He objected that such a course would plainly violate the international laws of naval war (and the German navy’s own Naval Prize Regulations, which required strict adherence to accepted rules for the capture of merchant vessels); moreover, the danger of accidentally sinking neutral shipping might bring America or other neutral powers into the war against Germany. The naval staff, however, soon received astonishing proof of what the U-boats could do if given the opportunity. In a few brief cruises in and around the British Isles, a half dozen of Bauer’s U-boats had quickly dispatched seven British warships: five cruisers, a submarine, and a seaplane carrier. The events caused “a decisive turn” in Germany’s naval thinking, recalled Admiral Reinhard Scheer, who would succeed Pohl as commander of the High Seas Fleet a year later. “The submarine,” Scheer wrote in his memoirs of the war, “from being merely a coastal defense machine, as was originally planned, became the most effective long-range weapon.”
²¹

Britain gave Germany’s naval staff the justification it was already looking for a month later. On November 2, Britain declared the entire North Sea a “war zone” and announced its intention of interdicting all ships carrying supplies “ultimately” destined for Germany. A blockade of an enemy’s port, closing it to all shipping, including that of neutral countries, is a perfectly legal exercise of belligerent powers, but the laws of naval war had always imposed stringent obligations on a blockading force to ensure that it did not simply become a legal loophole which would render meaningless the rights of neutral traders. A blockade had to be openly declared, restricted to specifically named ports or coastal waterways, and maintained with sufficient force as to block all access to those places: “paper blockades” had always been illegal because they would be little more than an excuse for seizing neutral ships wherever they were encountered on the high seas, captures that would never be permitted otherwise under admiralty law. Britain was doing exactly what the laws of naval war forbid, suspending the rights of neutrals to traverse an entire sea and, worse, threatening to seize even neutral noncontraband cargos destined for neutral ports—in Denmark, Norway, Sweden, and Holland—if, according to Britain, those goods might eventually be reexported to Germany.

The senior officers of the High Seas Fleet now added their weight behind
Bauer’s proposal, arguing in a memorandum to Pohl that an unrestricted U-boat campaign against all merchant ships trading with Britain could be decisive. Sinking both enemy and neutral merchantmen without warning would not only be a necessity in such a campaign, given the nature of the U-boat, but an actual virtue as well, since shipowners would quickly be unable to find crews willing to face such an appalling menace:

In a decree published on February 4, 1915, Pohl declared the entire waters around Great Britain a war zone as of February 18, warning that “owing to the hazards of naval warfare” it might not “always be possible” to distinguish neutral from enemy ships. In the next three months the U-boats sank a quarter million tons of shipping, including the Cunard liner
Lusitania
, torn open by a single torpedo fired from
U-20
on May 7. The death toll, 1,198 passengers and crew including 128 Americans, horrified the world and set off a wave of anti-German feeling in America, all the more so when it became clear that German public opinion was defiant, even exultant, over
this triumph of German arms: German newspapers loudly justified the act, insisting that the
Lusitania
was an “armed auxiliary cruiser.” The U.S. State Department delivered a formal diplomatic note to Berlin protesting “the practical impossibility of employing submarines in the destruction of commerce without disregarding those rules of fairness, reason, justice, and humanity, which all modern opinion regards as imperative.”
²³

The exchange of notes went on for months, while behind the scenes Germany’s civilian leadership struggled to contain the crisis. Germany’s chancellor said he felt he was “sitting on top of a volcano”: at any moment another young U-boat captain might at the push of a button bring America into the war. Considerably complicating his position was the fact that both the German navy and the German public overwhelmingly approved of the no-holds-barred U-boat offensive. In late August he sent the United States reassurance that henceforth Germany would scrupulously follow its prize regulations and avoid attacking neutral ships or passenger liners. In September 1915, after the volcano nearly erupted again following the torpedoing of two British passenger ships, the
Arabic
and the
Hesperian
, Germany effectively suspended the campaign altogether, withdrawing its U-boats from British waters. But to Admiral Scheer, the justice—and hard logic—of U-boat warfare, for all of its inescapable brutality, remained firmly on the other side:

SCHEER RIGHTLY SAW
that the U-boat offensive struck a direct blow not only at Britain’s naval power, but even more deeply at British complacency and tradition. For half a dozen generations the ascendancy of the Royal Navy had seemed to the British people as a simple fact, if not a law of nature—or perhaps even a birthright due the British race by virtue of its very being. For more than a century the Royal Navy had been the largest in
the world. In 1889 the British government had gone even further, adopting a policy requiring Britain’s navy to be larger than the next
two
largest navies in the world combined. Britannia had for so long ruled the waves that it had become simply inconceivable to think otherwise.