"It looks as if the ship will stay afloat only for a very short time. [Ordered] dive to 25 metres and leave the area seawards. I couldn't have fired another torpedo into this mass of humans desperately trying to save themselves."

Kptlt. Schwieger - Log entry made 15 minutes after firing the torpedo at RMS Lusitania. 

At 1.20pm on 7th May 1915, the U-20 surfaced (only ten miles from the coast of Ireland) to recharge her batteries. Soon afterwards Captain Schwieger, the commander of the German U-Boat, observed the Lusitania in the distance. Despite the liner's size and configuration, Schwieger did not immediately recognise her and even momentarily thought that, instead of seeing a vessel with 4 funnels, he was perhaps looking at 2 ships overlapping his viewpoint.  

Schwieger gave the order to close the distance between U-20 and the newly-acquired target. His boat had been at sea for seven days and had sunk two liners on that patrol; only two torpedoes were left. At this point, Lusitania made a slow turn towards the hunter - thus giving it a good firing solution. A similar movement away from U-20 would probably have put the liner out of range and allowed her to escape without adding to her speed.

Schwieger ordered the release of a torpedo from a distance of 700 - 750 metres - without assuming that a single strike would sink such a large vessel. However, it soon became clear that the Lusitania was mortally wounded and bound for the bottom. Schwieger declined to use his last torpedo - that measure did not appear necessary and he was unwilling to send it through a sea that was suddenly full of people who were fighting for survival. He mentioned that latter point in a log entry as U-20 slipped away from the scene; afterwards, he was unfairly accused of adding the comment in order to feign concern for the Cunarder's crew and passengers.

Some historians and politically-motivated commentators went even further by creating the myth that Schwieger actually did fire a second torpedo - a rewriting of the facts which conveniently provided an excuse for the eruption of a second explosion on board Lusitania (some time after the blast caused by the only  genuine torpedo hit).

After that 'extra' (allegedly larger) explosion, the Lusitania rolled over and sank in around eighteen minutes. The exact time she took to founder is still the subject of debate - though most authorities agree that it was less than 25 minutes. A total of 1,198 people died (785 passengers and 413 crew) - including 128 American citizens.

After the storm of protest caused by the Lusitania disaster, the Kaiser called a halt to unrestricted submarine warfare. This caused a temporary lull in sinkings, though Schwieger and U-20 managed to sink the defensively-armed White Star liner Cymric during this period. Unbeknownst to Schwieger, the liner was carrying the body of one of the Lusitania victims home to America at the time.

On November 5th, 1916 - whilst trying to assist another U-boat - the U-20 ran aground in fog off the Danish coast. She resisted all efforts to refloat her - the suction effect of the wet sands kept her stranded. After several lines and chains had been broken during failed towing attempts, the crew detonated one of their own torpedoes to render their boat useless to the enemy. During the attempt to recover U-20, the battleship Kronprinz Wilhelm and another warship which were covering the operation were torpedoed (but not sunk) by the British submarine J1.

Schwieger was awarded the Pour Le Merite on 30th July, 1917; he was killed in action on 5th September. His vessel, U-88, was pursued by the Q-Ship HMS Stonecrop; during the chase, the submerged U-boat struck a British laid mine off the Frisian island of Terschelling in the North Sea. None of the German crew survived the subsequent explosion. The British credited HMS Stonecrop with a victory, though that vesel had nothing to do with the laying of the fatal mine and she had not fired upon U-88 with any effect during the pursuit.

In the course of 12 operational patrols, Schweiger sank 190,000 tons of enemy shipping - becoming the seventh highest scoring German U-boat commander of The Great War ( World War I) . The wreck of U-20 was plainly visible and almost intact for a number of years;  in 1917, the Secretary of the Danish Navy decided to salvage all useful items from the submarine which still lay close to the beach by Vrist.

Instruments, copper tubing and the 88mm deck-gun were removed and taken to naval headquarters at Holmen in Copenhagen. At the end of the war in 1918, the gun was deactivated and became, for many years, an exhibit in the Navy Museum (it now stands in Strandings Museum in Thorsminde). The submarine's bell was salvaged and retained until 1976 (when Denmark formally returned it to Germany).

The wrecked U-20 was dynamited by the Danish authorities some time during 1925 (some sources declare the reasons to be unknown - other researchers suggest that the Secretary of the Navy ordered the demolition to remove a potential hazard to navigation). The remains lay where they came to rest for decades - forgotten, unrecorded and unsought.

During 1984, the skeleton of U-20 was discovered. 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. U-20 was found in only 17 feet of water - partially buried in the continually shifting sand.

U-20 was resting nearly on the beach in 1916. At present, due to coastline changes, she is over 300 yards from land. Her conning tower, ripped off in a 1924 demolition attempt, lies nearby. She was positively identified after divers found an engraved brass plaque on a propeller shaft coupling - it provided the manufacturer’s name and the date of installation. According to the most recently available accounts, the wreck of U-20 has not, been pillaged by souvenir hunters, nor is it regularly frequented by divers, though the remains are quite close to shore.