‘He has made several attempts to break our fence . . . ‘

Over the summer of 1918, following the German gains of the Spring Offensive on the Western front, things were changing rapidly as the Allies began to regain territory. The French counter-attacked on the Marne on 18 July, while from 8 August onwards the Battle of Amiens saw the Allies advancing, pushing the Germans back eastward in the final push, a period known as the 100 Days’ Offensive.

At sea too, things were changing rapidly, as demonstrated by UB-109‘s final voyage. Throughout the war the Straits of Dover had been a heavily contested area with high levels of submarine activity and both British and German minefields. Over 1917-18 the Straits were increasingly fortified both on land and at sea, taking advantage of new surveillance technologies and improving the Dover Barrage, which became a formidable defence against U-boats. (1)

At this stage of the war British newspapers were making bold claims about the success of the Dover Barrage: ‘The enemy has found it such an annoyance, and so great a barrier to the activities of his U craft, he has made several attempts to break our fence, but his attacks have only resulted in severe losses for him. Blocked by our old sunken cruisers, barred by the Dover barrier, and bombed without cessation from the air, the German Flanders flotillas have become almost useless.’ claimed one paper. (2)

Another stated: ‘All Ostend and Zeebrugge submarines have now been practically barred from going through the Straits of Dover. Those only capable of short distance work turned to the North Sea . . . The short distance fleet having been practically wiped out, Germany reinforced her Flanders flotillas with long distance submarines. These are not going through the Straits of Dover in any numbers. Some, manned by men of a sporting type, who volunteer to make a dash for it, do get through. We get others in the attempt.’ (3)

One of those who ‘got through’ was UB-109, which slipped out of Zeebrugge in the early hours of 28 July 1918. She was making a long-distance voyage for a U-boat of her UBIII class, which were normally used on coastal torpedo attack operations and as such were normally operational in the North Sea and English Channel. Under the experienced command of Kapitänleutnant Kurt Ramien, who had previously commanded UC–1 and UC–48, she was bound for an Atlantic patrol off the Azores.

It certainly required courage to negotiate the Dover Barrage, which could justifiably be described as a sea ‘fence’, as described in the newspapers. At this late stage in the war it was a double fence at either end of the Straits of Dover (illustrated Figure 9 in the UB-109 report) with a net barrage between the Goodwins and Dyck in Belgium to the north-east, reinforced by an array of deep mines SE of the South Foreland, as if it were a moat or trench behind the line. To the south-west the Folkestone Mine Barrage stretched between Folkestone and Cap Gris-Nez in France, broken only by the dangerous sandbank of the Varne. This barrage was laid in rows with mines in each row set at increasingly greater depths westward. so that submarines were either forced to surface, when they stood a great chance of being spotted by patrols, or dive, when they would be forced to battle through mines laid at varying depths.

Ramien and UB-109 just scraped through unscathed outward-bound, after lying submerged on the Bligh Bank off the Belgian coast during daylight hours. (4) The westward flow of the tide eased their passage through the barrage, but technical problems with the hydroplane motor forced them to break surface, where they were attacked by patrol vessels near the Folkestone Mine Barrage and forced to dive once more.

In the meantime, of course, this minefield presented an obvious problem for the British, Allied and neutral shipping which also had to pass through the Straits of Dover. There was actually a gap in the ‘fence’ just off Folkestone maintained for friendly shipping, known as the Folkestone Gate, and the depth of the mines was calculated to increase the risk to submarines and minimise the risk to surface vessels. However, while Ramien was out in the Atlantic, the British closed the ‘gap in the fence’ with a field of shore-controlled mines.

These defences were in place by the beginning of the second week of August. Some time after 8 August, UC-71 struck one of these new mines, but managed to limp through the barrage back to base and resume patrol in September 1917. Her escape alerted the German authorities to the new deployment and a radio warning was put out. (5)

For some reason UB-109 was apparently unaware of the warning as she began her return voyage after 16 August.  Secondary sources attempt to explain this away by the removal of his radio masts but this is not substantiated in contemporary source material – could he simply have been out of range? His submarine’s return passage can be marked by her victims:  one ship sunk on 19 August NE of the Azores, and two off the coast of Brittany on 25-26 August.

In the early hours of 29 August Ramien attempted once more to pass through the supposed ‘gate’. As usual in these First World War narratives, accounts of what happened next differ slightly, but essentially a patrol vessel blocking the ‘gate’ forced UB-109 to alter course and as the U-boat submerged she entered a shore-controlled minefield. It is also unclear exactly how the field was controlled: attributed either to a listening station at Shakespeare Cliff, Dover, or to a Bragg or induction loop (similar to modern assistive technology now employed to help deaf and hard-of-hearing people hear in public places) although other sources attribute no operational successes to the Bragg loop until October 1918. (6)

British interrogation reports reveal that the survivors couldn’t hear each other as they tried to escape, temporarily deafened by the change in air pressure as water rushed in. (7) After a struggle to open the conning tower hatch, there was another struggle to get free as Ramien and two other survivors became wedged in together. Out of a crew of 36, only eight would survive, to be taken prisoner.

The wreck was found and buoyed ‘broken nearly in half’ on the following morning by the famous ‘Tin Openers’ (naval intelligence divers) who searched the wreck for any revealing material. Possibly because of secrecy surrounding their operations, there is no apparent history of the wreck being charted in 1918, however – the site would not be charted for another 60 years when it was rediscovered. It is seen to be lying in two parts, certainly at least characteristic of mine blast damage. More specifically, she is noted to have greater damage aft of the conning tower, consistent with contemporary ‘Tin Opener’ reports which noted this.

Her propellers are no longer in situ but reports suggest that one was stamped UB-109 and the other UB-104, possibly indicating a shortage of spare parts within the Flanders Flotilla in a service context (antedating the loss of UB-104 in September 1918).  (8)

However, these propellers, which could hold the key to the vessel’s identification, remain untraced. There are some alternative explanations for the UB-104 reading: corrosion damage, superimposed numbering, or misreading of the stamp: numbers on metal from a maritime context can be extremely difficult to decipher (which we will cover again in a forthcoming post). On the balance of probabilities, this wreck is very likely to be UB-109.

(1) Firth, A. 2014 East Coast War Channels in the First and Second World Wars Research Report for Historic England 103/2014; Wessex Archaeology. 2015 UB-109, off Folkestone, Kent: Archaeological Report Research Report for Historic England 123/2015

(2) Sunday Post, No.682, Sunday 8 September 1918, p6

(3) Aberdeen Press and Journal, No.19,869, Friday 6 September 1918, p3

(4) Wessex Archaeology 2015

(5) Wessex Archaeology 2015; uboat.net

(6) Wessex Archaeology 2015; Grant, R. 1964 U-boats destroyed: the effect of anti-submarine warfare 1914-1918 London: Putnam; McDonald, K. 1994 Dive Kent: a diver guide Teddington: Underwater World Publications; Walding, R. 2009 “Bragg & Mitchell’s Anti-Submarine Loop”, Australian Physics 46 (2009), pp140-145

(7) Messimer, D. 2002. Verschollen: World War I U-boat Losses Annapolis: Naval Institute Press; Wessex Archaeology 2015

(8) Wessex Archaeology 2015

(9) Endress, F. c.1919 (facsimile edition 2012) Handgeschriebene Schriften: Schriftenvorlagen für einfache und leichtauszufuhrende Beschriftungen in verschiedenartiger Anwendung, in der Technik, fur Gewerbe, Schule und Haus, auch fur den Selbstunterricht zusammengestellt Mainz: Verlag Hermann Schmidt