In 1914 as the world plunged into war, a new weapon - the undersea warship - was entering wide service in the arsenals of several nations. Within the Kaiserliche Marine (Imperial German Navy) the newly formed Unterseeboot service formed an important part of their combat strength. The second year of war 1915 witnessed one of the most monumental events of the First World War, and a shipping disaster long remembered by all nations. This sinking of the Lusitania had been a perfect demonstration of the new U-boats’ ruthless effectiveness in the hands of a determined commander. 

^{An ocean-going  WW1 German U-Boat leaves for patrol}

By the end of 1914 Germany’s Admirals were becoming increasingly aware that their submarines (only 28 in commission by that stage) were incapable of inflicting the crippling blockade on British trade envisaged by strategic planners. The small vessels were unable to adopt the orthodox methods of intercepting enemy shipping on the surface and taking the vessel as prize. U-boat commanders found their ships exceedingly vulnerable to counter-attack while surfaced, particularly after the British First Lord of the Admiralty Winston Churchill urged merchant ship captains to ram German submarines when they surfaced. The age of unrestricted submarine warfare was ushered into being, and in February 1915 the German Government declared a policy of attacking and sinking any ships found within a stated blockade zone, which surrounded Britain and Ireland. They further declared that while all efforts would be made not to sink neutral vessels their safety could not be guaranteed within that area. Notices were run in American papers warning that ships sporting the British flag risked attack and destruction. 

Finally on 7^th May 1915 the almost inevitable result of such a policy occurred. Cunard cruise ship Lusitania was torpedoed and sunk just off the Southwestern Irish coast. Of the 2 000 people aboard, 1 200 were drowned, including 128 neutral Americans. The U-boat responsible was U20 one of the “U19” Class of ocean going submarines, built before the outbreak of the First World War. There were only five vessels within this group, numbered consecutively U19 to U23. Robust and seaworthy these undersea hunters were 64.2 metres in length, with a beam of 6.1 metres and draught of 3.6 metres, displacing 650 tons while surfaced and 837 tons submerged. Twin diesels pushed the boats at a maximum of 15.4 knots when surfaced, electric engines for running beneath the waves providing 9.5 knots.  The teeth of these submarines comprised a single 88mm cannon mounted forward of the conning tower, two bow and two stern torpedo tubes, for which she was capable of hauling six torpedoes. The 35-man crew lived in the same hellish conditions that all pioneering submariners enjoyed so much. 

The sinking of the Lusitania still raises ire and debate amongst people today. While a tragic and unprecedented event, the label “War Criminal”, used by many, sits uneasily on the shoulders of U20’s commander Kapitänleutnant Walter Schweiger. The barbarity of “total war” was not new to the world; civilians had suffered during conflict for centuries, most recently perhaps to people of the early 1900s in South Africa at the century’s turn. However weapons had increased in their destructive power, and the remoteness of their operation. Long range devastation facilitated by technological advances. Arguments over Schweiger’s criminality continue. The beautiful cruise liner had been carrying contraband goods through the blockade zone, in the form of explosives and ammunition bound for the nightmare of the trenches in France. Although unarmed, she still carried gun mountings from her previous requisitioning by the British Admiralty, and was officially listed as an Armed Merchant Cruiser. A single torpedo hit the Lusitania; U20’s last. The great liner took only 18 minutes to go under after a second explosion contributed to her mortal damage. This second explosion also has given rise to years of speculation and debate. The two most likely causes being either a sympathetic detonation of stored ammunition, or highly flammable coal dust in her storage bunkers ignited by the torpedo explosion. Bodies of men, women and children continued to wash up on the shores of a stunned Ireland for weeks. 

Schweiger received the Iron Cross from an unrepentant High Command for his sinking of the Cruise ship. During the next year he steadily increased his personal score, affirming his position as one of Germany’s new U-boat Aces. However the days of U20 were numbered. In October 1916 while running surfaced close to the shore of Denmark’s Jutland Peninsular the submarine abruptly slammed to a halt, throwing members of her crew to the steel decking. After frantically searching for the cause of their grounding Schweiger’s navigation officer discovered that there was no error with his previously laid course but rather the compass by which the boat was conned. They had shaved the coastline too closely and were stuck fast in thick glutinous sand of a shallow bank, within plain sight from the wide sweeping expanse of Vielby Beach. 

Following a rapid radio call for assistance, nearby German destroyers arrived and attempted to pull the boat free. However the suction of the wet sand was too great and after several broken tow chains and growing fear that their exposed position would soon attract British attention, Schweiger ordered his ship abandoned and scuttled. Charges were detonated in U20’s hull and she was left lying listlessly half exposed near Denmark’s sandy shore, the bottom ripped open. Schweiger later went on to command the newer U88 adding to his victories until 17^th September 1917 when his ship rubbed against the contact spikes of a British mine, and was destroyed with all of her crew. After 12 operational patrols Schweiger had sunk 190 000 tons of enemy shipping, becoming the seventh highest scoring German U-boat commander of World War One, though probably the most notorious. The wreck of U20 plainly visible and almost intact was dynamited by Danish authorities during 1925 for reasons unknown, the remains lying for years forgotten and unrecorded. 

During 1984 the skeleton of U20 was found once more. American author Clive Cussler financed an exploratory search of the region (documented in his book “The Sea Hunters”) with the help of Danish archaeologist Gert Normann Anderson. U20 was found to lie in only 17 feet of water, partially buried in the continually shifting sand. Her conning tower, ripped off in the 1924 demolition attempt, lies nearby. She was positively identified after divers found an engraved brass plaque on her propeller shaft coupling, giving the manufacturer’s name and the date of installation.

The wreck of U20 has not been pillaged by souvenir hunters, like many others to be found so close to shore. In actual fact there are considerably more divers exploring the deep wreck of the Lusitania using mixed gas tri-mix equipment.  The German submarine is not regularly frequented by divers and she rests in place corroding over time. Perhaps one day an officially sanctioned artefact retrieval operation could be mounted. If so the pieces should be displayed in a relevant museum. What would these items commemorate?  The author is of the opinion that such a display would remember those who died at the hands of U20’s weaponry, aboard the Lusitania and other ships. It would also serve as a memorial to men of the U-boats - indeed all submarines - that gave their lives in two world wars fighting for their countries.