Conning Tower
The U-Boat which sank the Lusitania  

Salvage and wreck-removal of the U-20

Translated from German and Danish texts. Certain technical terms seemed to have no direct English translation - in some case I have guessed in the meanings as shown within square brackets. - Paddy O'Sullivan.

The demise of the U-20 on the Jutland Sands

Introduction - The story of the U-20

U-20, when she was new

U-20, when she was new

In the Autumn of 1916 Commander Schwieger had completed a routine patrol of Western waters in his submarine U-20 and was making his return voyage to Germany to replenish his supplies. As he neared the German coast he responded to a wireless call for assistance from the U-30; this luckless submarine had suffered engine failure while patrolling twenty-five miles off Bergen, in Norway. The two submarines eventually met up and proceeded to Bovsberg on the Jutland peninsula. As they neared their destination, fog descended and blinded the commanders resulting in both their submarines running aground on the Jutland sands. The U-30 was subsequently refloated and dragged off the sandbank; however, its partner the U-20, remained fast despite strenuous efforts by the German Imperial Navy to refloat the vessel. The story of what followed is taken up by an account of a local newspaper man who witnessed the stranding.
The daily newspaper reporter arrived at the beach at 10 a.m. and described the U-20 as being painted grey, of impressive size and no more than 30-meters distant from the land. He also noted that a heavy sea was running and the stranded boat showed signs of heaving in the breaking surf; he further noted that the commander (Schwieger) was standing in the conning tower with some of his colleagues huddled about him - all were looking at the torpedo boats which crissed-crossed the scene as they slowly cruised to and fro. Earlier in the morning Vice Admiral Scheer of the Imperial German Navy had dispatched the battle cruiser Molkte and a squadron of destroyers to assist the floundering submarine. The intrepid reporter noted that fourteen ships in total had been sent to the scene and that by morning the number had reduced to four. From time to time a signalman on the submarine was seen to communicate with the big ships in distance by use of two flags.
Not to be outdone the local lifeboat also attended the scene and suggested to the locals that the stranding must have occurred the previous evening's fog between between 1900 and 2200 hours. In the early hours of the morning the u-boat sent rocket signals but the source of the signals could not be identified until morning dawned. In response to the rocket signals the lifeboat put to sea at 0800 hours and approached the commander in his conning tower to offer help. The commander would have no truck with the local people and refused assistance stating the matter was being taken care of by the torpedo boats. In the distance a torpedo boat was seen to launch a few of its own lifeboats which then proceeded to off load cases, sea sacks and crew members from the stricken U-20. Having experienced some difficulty with the rough seas a motor boat succeeded in getting a towing wire aboard U-20; the wire was secured to a stern chock and led out to a torpedo boat. At 10.30 a.m. officials began to arrive on the beach - among them the Chief of Police, Christensen, who demanded that the lifeboat put him on board as he wished to speak to the captain. As the lifeboat crew pushed their boat back in the water the u-boat commander noticed their efforts and shouted stop! as he reminded them that he did not want any officials on board. This action by the commander may have been a diversionary tactic to avoid a diplomatic incident between his country and neutral Denmark. The Police chief reluctantly accepted the refusal and remained on land.
Conning Tower of U-20

Conning Tower of U-20, now on display in the Stranding St. George Maritime Museum

By now the torpedo boat was straining at the towing wire which soon broke under the strain. The signalman recommenced his flutterings immediately as he flagged news of the latest turn of events to the distant ships. In response to his signals the ships boats were seen to approach the beleaguered submarine once more and take off all the luggage. Various article were thrown overboard as the mariners departed the stranded vessel in an orderly fashion. Only the Captain and his thin-faced signalman remained on board. It was decided to explode a torpedo in the tubes of the U-20 to prevent the vessel falling into enemy hands; it was feared that the allies might refloat the U-20 and return the Lusitania's assassin to England thus gaining a great propaganda victory in the process.
Having set an explosive timing device in the torpedo tubes the commander and his signalman turned to the beach once more and were alarmed to see that the hoards of curious spectators had now swelled to and estimated crowd of five hundred people. The signalman shouted through his loud hailer: ?torpedo - all away - all away'. Feeling that the strong winds were scattering his words he supported his warning efforts with hand signals and much waving to urge the people to vacate the beach. The commander now noticed that the police chief on the beach was calling to him directly but again the wind swept away his words; the commander gestured back that he could not hear and again made hand-signals in vain to urge the people to clear the area; the time was now 12.00 noon. The commander's final act was to set the German flag at half-mast before abandoning his craft accompanied by his trusted signalman. The sight of the last two men leaving the stranded submarine send a sudden jolt of panic through the motionless onlookers; some ran north while others ran south as they dashed toward the horizon and safety. Unfortunately, the majority put curiosity before safety and merely relocated themselves behind the nearby sand dunes to crouch low in the wind-blown marram grass and observe the saga unfolding.
However, the next event to occur raised tension and fear to an unbearable pitch.
Deck gun of U-20

Deck gun of U-20, now on display in the Stranding St. George maritime museum

The motor boat that had picked up the commander and his signal man was seized by great wave and driven ashore until it too became stranded on the shallow Jutland sands. The engine stopped immediately as terror-stricken sailors fumbled for non existent oars. Soon they were clutching at floor boards and any implement that could be used to row; they made slight progress in bumping the boat off the sand and rowing towards the north.
Deck gun of U-20, in situ

Deck gun of U-20 in situ

Meanwhile the signalman resumed his flagging to announce the new crises that had erupted in the motor-boat. Unfortunately the minutes were ticking out fast and before they could make any real progress an almighty explosion occurred on the submarine exactly ten minutes after the boat had motored away. Thick black smoke poured out of the submarine and in no time large plumes rising skyward blotted out a great part of the sky. A blast wave from the explosion toppled the sand dune spectators; many were blown off their feet; others were slammed down the steep slopes of the sandbank.
A cameraman who had set up his apparatus on a tripod was blown off his feet before he could click his shutter; his camera and tripod were also flattened in the blast. Within seconds a hail of steel wreckage rained down from the skys and peppered the sand dunes where the spectators had taken cover. The reporter recorded that one fragment of twisted plating was about a meter square and one centimeter thick. On the strand and 200-meters from the wreckage a piece of torn decking estimated to be three square meters landed on the beach; its jagged edges buckled out of recognition. Several steel fragments and machine parts rained down on the local railway; 1500 meters distant from the explosion. To everybody's surprise the limping motor boat: the nearest object to the blast still appeared to be intact after the explosion - its crew members appeared to show signs of life. Soon the dazed spectators on the beach staggered back to their feet; many were surprised to find their bones still intact - all now realised that they had been well within the danger zone when the blast occurred. Within minutes the sand dunes were alive with chatter as neighbours enquired about each other's well being. One spectator in the large crowd: a fishmonger from Lemvig, was deeply moved by the event. He stood erect and took off his cap as a mark of respect as he stared at the wrecked submarine; with tear-filled eyes he was seen to murmur silent words to himself. The entire forecastle of the submarine had been torn asunder in the blast; however, the mid and aft sections remained intact.
U-20, abandoned

U-20, abandoned, note flag at half mast

Miraculously, not a single person had been killed or maimed in the hurricane of iron from the sky; some of the fallen fragments were subsequently collected as souvenirs by the civilian spectators as they departed the beach for home; no doubt the excitement of the day would remain etched on their memories for many a long day. The torpedo boats which had been mere silhouettes on the horizon prior to the blast began to close in on the Jutland sands once again; as they approached Commander Schwieger's stranded craft a small rowing boat was launched and all personnel were transferred to torpedo boat. Soon the ships vanished over the horizon and the Jutland sands were returned to the sea birds. As hopes of refloating the stranded U-20 were abandoned the Danish authorities decided to implement the full rigours of International law by impounding the stricken submarine and prevent it falling into either German or Allied hands.
The Danish Ministry of the Marine placed a watch on the site. It was later decided that the exploded remains of the submarine were past all hope of refloating and the watch was called off.
Schwieger did not leave us an account of his hair-raising experience in his marooned motor boat - however, we can assume that he was none the worse for wear after the event. During his term as U-20 commander from December 1914 until its suicide in November 1916 he had sunk 36 ships of total tonnage 144,300 tons. Up to 6 May 1915 Schwieger was an unknown U-boat commander; twenty four hours later he became the most hated man in the world by sinking the Lusitania; for this act the Kaiser awarded him the pour le merite. After the Jutland incident, Schwieger was given command of the bigger submarine, U-88. Four months after the Lusitania sinking Schwieger defied the Kaiser's ban on sinking passenger liners when he stalked and torpedoed the Alan liner Hesperian west of Fastnet. The Hesperian had 653 passengers and crew aboard; miraculously only 32 people lost their lives as the liner sunk miles 85 miles south-west of Fastnet.
In the weeks that followed Schwieger torpedoed and sank five more steamers: the Duro, the Rea, the Dictator, the Bordeaux and the Caroni. A year and a day after sinking the Lusitania, Schwieger encountered the White Star liner, Cymric, 140 miles west of Fastnet. Schwieger launched three torpedoes at the Cymric[l/ugship] which sank after several hours with a loss of six lives out of 110 crew members; the vessel had no passengers on board. However, the trigger-happy u-boat commander's days were numbered and his submarine, U-88 would soon become his steel coffin. In 1917 as he set out on patrol his submarine struck a mine off Heligoland - the resultant explosion sent him plunging to a watery grave with all hands. Schwieger perished at his own game; many would say poetic justice had been done.

The salvage of the wreck circa 1918 - 25

U-20, in 1916

U-20, in 1916

Recognising that the wreck was a hazard to shipping the authorities faced up to the fact that its removal was now a Danish problem. On 18 March 1918 the authorities sold the remains of the U-20 for 12,000 Danish crones to the Copenhagen firm of Petersen and Albeck. The new owners subsequently did a deal with a specialised sub-contractor in Harboor - a man named Jens H. Ronn.
U-20, in 1925

U-20, in 1925

The new deal saw Ronn acquire one-third ownership of the wreck; he would also salvage the vessel and remove the wreck completely as required by Danish stranding law; he would receive 42% in value of all (nonferrous) metal (such as brass, copper and lead) recovered. With the legalities complete in April, Ronn now complicated the issue further by appointing his own subcontractor, a salvage company named Sondre Bjevgelang - based in Harboor-south; U. Kruse and Chr. Vrist signed the contract on behalf of the third subcontractor to enter the scene; work started immediately. The after-deck was first tackled at low tide and later everything that could be removed was taken off. Many people in the area picked up (brass) metal parts as souvenirs which the salvage men melted down to make copies of the U-boat's bell. In 1921 the salvage men finally gave up their task and passed on the wreck removal work to a Claus Sorensen from Esbjerg for an agreed sum of 2,500 crones. Jens Ronn, who owned the overall contract agreed. Sorensen was to become the fourth subcontractor in a complex tangle of salvage legalities.
In one of his books Claus Sorensen later wrote: Inside the U-20 was a rich store of valuable metal and lead from the batteries, at first it was his idea to bring the whole boat on land and use it as a restaurant. The forecastle was wrought (torn) off the main body and the ship was full of sand and gravel which had entered via the open rivet holes. Cutting gear was used to access portions of the wreck and soon a special pump was set up to suck out the sand and gravel, the pump worked beautifully until the abrasive sand caused such rapid wear of parts that it had to be returned to Esbjerg for repairs. In frustration the salvage men stood idly by as two weeks of beautiful weather passed in anticipation of the pumps return. In preparation for lifting - divers had plugged several hundred holes with wooden stoppers; on one occasion a diver had somehow become stuck in the sand and extra divers were sent down to dig him free with shovels. A new impeller was fitted to the sand-pump in due course and it was returned to the wreck to commence sand-clearing operations; work had barely started when the weather broke and stormy seas began to wash over the wreck causing salvage to be abandoned.
As the autumn days passed the severity of the storm became more intense and when it finally blew it itself out it was found that the ever-shifting sands had moved yet again - the wreck was now 70-meters off the beach. At this stage Sorensen had blasted and recovered 2,500 kilos of (non-ferrous) metal parts and stated that nothing of value was left on the wreck. With the onset of winter all salvage attempts were abandoned.
On realising that he was stuck in a contract which obliged him to remove the entire wreck and that any further work would incur nothing but expense he tried to shed his responsibility. He now suggested to Ministry of the Marine that the wreck be allowed to remain where it sat as he feared for the lives of his divers due to the presence of so many grenades on board. Petersen and Albeck, the original owners, were presented with a copy of Sorensen's letter which they appear to have read with some indignation; They subsequently wrote to Jens Ronn (the second contractor in the salvage) as follows: “From Claus Sorensen of Esbjerg we have received a peculiar letter today. It states that he is no longer in favour of blowing up the wreck. He enclosed a drawing with the exact position of the wreck and added his belief that the wreck would sink deeper and deeper into the sand in time. This justifies his decision by saying that there is a store of grenades inside the wreck which would make further work too dangerous. Mr Sorensen wishes the Department of the Marine to relieve him of his obligation concerning the wreck. This is against the rule! as this is the first mention of grenades which are meant to be partly in boxes and partly strewn around - we find his request most peculiar. Secondly we do not understand why Mr Sorensen takes up correspondence with the Department of the Marine about a wreck which does even belong to him. After all it is our right to decide whether we want to be rid of the obligation to blow up the wreck. Mr Sorensen could have informed us about the possible dangers. We are certain that the Ministry will inform Mr Sorensen that this is not his responsibility - because after all we are the owners of the wreck.
The Ministry requested Mr Sorensen to remove the wreck completely from the seabed. The Ministry was helpful to a degree, it sent the necessary explosives (the 70-kilo gun-cotton mines) to Claus Sorensen via Jens Ronn”'
The big occasion (the explosion) was scheduled for August 1925. The daily newspaper of the west coast, the Dagbladet Vestkysten, describes the day as follows:
U-20, in 1925

Thorwald Neilsen

“We are having breakfast at Harboor Strand Hotel, salvage undertaker ,Claus Sorensen, Inspector Staarck from the Ministry of Marine, diver Thorwald Nielsen, and yours truly (the newspaper reporter). The conversation between the aforenamed named gentlemen is of an explosive nature. The subject is difficult and dangerous salvage work. During the conversation I realise that Claus Sorensen is viewed by the Ministry as a highly competent and reliable person in spite of his young age, and that one could definitely entrust him with this dangerous job in good conscience. Claus Sorensen is a smart fellow in his head as well as with his hands. As soon as the last bite had been swallowed we are off to the dunes in full flight so that the long puddles on the road spatter everybody and anything. Out in the dunes a small group of Harboor fishermen await us. Only half a minute after arrival, Claus Sorensen, has everybody moving. A dozen boxes are being dragged out of the ammunition shed - out of each one rolls a heavy mine of cylindrical shape; each containing 70-kilos of shooting-cotton. The mines are being supplied with electric wiring and transported down the strand. About 60-meters out, the rusty conning tower can be seen - for nine years it has survived wind and waves and defied the breakers. Scarcely a dent is visible in the heavy plating. From the top of the tower a rope leads to land. Diver Thorwald Nielsen has donned his diving suit; two men man the air pump and Nielsen waddles off into the uneven swell. Soon he has vanished under the water - only a line of bubbles marks his progress to the wreck. Meanwhile five of the primed mines have been loaded onto a small boat. This is being pushed into the water and brought out to the wreck under the guidance of Claus Sorensen; the previous day had seen Nielsen inspect the wreck while Sorensen took soundings. The survey established the following: the wreck is about 60m long, and 4-5 meters high, it has double walls; the outer walls are badly damaged from past explosions and the weather while the inner wall is largely intact. The prow is separated from the ship but attached by bottom plating.

attach the rope

attach the rope

In its prow two torpedo guns (tubes) are situated as well as a magazine with grenades. A separate compartment behind the break in the prow housed two torpedoes and 200 grenades were noted further aft in the battery compartment. Five more grenades were found behind the machine room and the aft ship is nearly filled with grenades. There are also two large boxes filled with grenades beside the wreck and some single grenades. It is peppered with explosives. That Monday two trial explosions take place under the torpedoes; they have torn two large holes into the ships bottom and sand begins to pour out so that now the mines can be used with better effect. The first five mines were placed in the aft ship: one beneath the rearpoint (stern) two in the machine room, one fairly deep in the tower and one outside the aft ship. The empty boat now headed back to the strand to pick up more mines. Claus Sorensen climbs up the tower and bundles all the fuse wires together, Nielsen climbs up on the rump (hull) to rest awhile; he looks like a sea monster with the water moving gently around him. (see photo). His rest is short, soon the boat is back with four more mines; two of these go beside the tower, the third into the accumulator room and the fourth into the stern with the two torpedoes. The fuses of the last four mines are being brought to the tower and added to the bundle.


The diver comes back on land and is immediately surrounded by curious onlookers from the public; as hero of the moment he is being photographed by all and sundry. The boat returns to the beach and the crew jump out. Claus Sorensen unravels a black cable from the roll under his arm. The cable runs to a shelter behind the dunes. All the preparation and priming of nine mines took three and a half hours. People ask Sorensen when will the explosion take place “in a quarter of an hour - exactly 12.00 hours” (he replies). By now 70 people have found shelter behind the dunes. A dozen or so courageous people stay sitting on the empty mine boxes behind the parapet: the salvage crew, a few photographers and yours truly (the newspaper man). At exactly 12.00 hours Claus Sorensen turns the switch on his 50-volt battery. And now: a strange heavy growling rumble like a half smothered tremendous sigh, not particularly strong, but in very deep tone, and then a wall of water rises up higher and higher; faster than the eye can follow. It spans the whole length of the boat, all mines exploded at the same time.
transporting the mines to the wreck

Transporting the mines to the wreck

For a moment the wall of water, about a 100-meters high seems to stand still and form a strange ragged-edged silhouette against the clouds. Then is sagged into itself while a rain of iron and metal pieces dropped into the sea and on the dunes. Nobody came to any harm. On sounding afterwards Clause Sorensen found 6 irons rods (?) one meter below the surface. Because of this several more explosions had to be made; creepy work for the diver who had to move in the murky water between the grenades but everything went well in the end the work was approved as having been satisfactorily concluded.”
The wreck lay undiscovered until 1954 when wreck-fisher: (wreck diver) named Domgaard from Flirthals became interested in it. He made contact with Petersen and Albeck. It was agreed that he would salvage the parts (scrap metal) and deliver it to Petersen and Albeck who agreed to pay him the current rate (for scrap). The widow Ronn was to receive one-third of 10% of all salvage value payable by Domgaard. The beach warden gave Domgaard the exact location and the wreck was soon located. Visibility was exceptionally good and the salvage ship which had a draught of 7-feet commenced work. The wreck was free of sand and fully open all the way. The machines (engines) stood free and they were able to remove two silencers which were sitting above the machines. They salvaged a torpedo gun (torpedo tube) and one propeller (see photo); the second propeller was hopelessly stuck in the sand and failed to break free after use of explosives.
U20 exploding

U-20 exploding

The salvage ship could not lift the tower as it was too heavy; however, it was dragged to the beach. In four days Domgaard salvaged enough (nonferrous) metal to be able to send two train wagons full to Petersen and Allbeck. However, they reneged on paying the agreed price and operations were broken off. Domgaard kept the propeller as a souvenir and placed it in front of his house at Hirthals.  

Relocated the U-20 in 1979

In February of 1979, diver: Gert Normann, and three of his colleagues: Kim, Toni and Lars set out to locate the U-20. Its exact location had been lost to time and the confusion caused by ever-shifting sandbanks. After much searching in the suspected location the divers found bits of wreckage sticking out of the sand on 16 April 1979.
They noted that the wreckage was on the second sandbank out from the coast and about 150 meters from the beach - Identification of the wreckage was impossible due to the heavy sand in the area. The search was abandoned to await a more favourable shift of the sandbank. The divers returned again in March 1980 to find the wreck now free of sand and lying in a hole on a hard gravel seabed. They describe the wreck as being ?heavily blown up' but noticed her two diesel motors standing in place. Rows of copper cable ran along the starboard side while the port side was taken up with copper piping. Two damaged propeller shafts were also noticed; the electric motors in the stern were gone. In the back of the boat sat two large undamaged engines (gearboxes?) with brass flanges and cogwheels. Behind the gears (on a brass plate) were engraved a whole series of numbers and the name of the boat U-20 . Outside the boat was strewn with wreckage including the (conning) tower a few meters distant on the starboard side. The thick glass on the tower was still intact despite having been subjected to past explosions. On the port side of the wreckage an ammunition box full of grenades was observed; also visible was a cylindrical object which the divers presume was one of the 70-kilo gun-cotton mines which must have failed to explode in the 1925 wreck demolition attempt; it was decided to give this sinister object a wide berth. Four large brass valves were also noted by the divers and presumed to be the valves used to flood the ballast tank.

Specification of U-20

Mines exploding on U-20

Mines exploding on U-20

The submarine U-20 belonged to a series of four: U-19 to U-22, built between 1911-13. They were the first U-boats for the high seas with twin walls (twin hulls?) and diesel motors. U-20 was launched on 18 December 1912 at the Imperial Dockyards of Danzig. It had a water displacement of 650-837 tons. Its length was 50.5 meters, width 4.05 meters and draught when above water 3.58 meters; at periscope depth its draught was 8.10 meters. The boat was fitted with M.A.N. diesel motors of 1200 horsepower and two bronze propellers. Speed above water was: 15.4 knots - beneath 9.5 knots; range 7600 sea miles; capacity to submerge to depth of 50 meters. Intake of diesel (fuel capacity) 87 tons.
The boat was armed with four 50 cm torpedo canon (tubes) and crewed by 35 men including 4 officers. U-20 operated mostly in the Atlantic, west of England and Ireland. In December of 1914 Captain Schwieger became its commander. With U-20 he sank 36 ships, total tonnage 144,300 register.

Standings St. George Museum, Jutland.

A recent exhibition of the U-20 has been set up in the local Museum. The conning tower may be seen here and also the deck-gun of the U-20. The said gun was recently donated by the Royal Danish Navy. The collection also has a plate from the Lusitania donated by this writer.  

The end. 16 January 2012

Paddy O'Sullivan.