The (short) life and death of UB -115

U-boat Go Forth ! And despite losses, allied technology, crew dilution and the spread of Marxism, they did just that.

While the wreck of UC-32 is well known, the presence of a second U-boat off Cresswell in Northumberland is perhaps less familiar. Like all wrecks it tells us a story. By the time that UB-115 set out on her first and last patrol in September 1918, the North Sea had become a cruel Darwinian arena, an arena in which no quarter was asked and none was given. Winning the undersea war depended upon technological innovation, economics and the flexibility to alter tactics. It also depended upon morale, guts and a bit of luck for good measure. Before we can understand what took place, it is appropriate to say something about the U-boats which brought war to our shores in late 1918 and the men who crewed them.

When Germany adopted a policy of unrestricted submarine warfare in 1917, it did so in the knowledge that only by harnessing the advantages of new technology could the KDM prevail against the Royal Navy. The U-boats which rampaged off the British East coast in late 1917 and 1918 were no longer the ‘canoes’ which had brought destruction to the shores of the North Sea coast in 1915, these were real submarines. The KDM placed its faith in the UC II mine-layers and UB III class of attack boats. UB-115 was one of these UB III boats and its technical details are given below.

The UB III class of attack boat. They were called attack boats because their function was to attack with torpedoes while the UC boats laid mines. UB-115 was identical. In this diagram the Wireless Transmission mast has been erected. Wireless transmissions played an increasingly important role for both sides as the War ground on. The Germans greatly underestimated Admiralty’s ability to intercept and decode transmissions

Type: UB III torpedo attack boat Builder: Blohm and Voss, Hamburg for KDM Ordered: 23.9.16 within the batch UB 103- UB 117
Keel Laid: Yard No 321  Launched:  4 November 1917 Commissioned: 28 May 1918 by Oblt. zur zee Reinhold Thomsen (27)

Before: Fascinating image of a UB III under construction at Kiel. The upper casing is not yet in place, nor has the conning tower received its protection. Unlike British submarines the conning tower is actually within the pressure hull and most U-boat commanders preferred to make their attacks from the chamber within the conning tower. The loading shaft for the single stern torpedo can clearly be seen and the support structure for the yet to be added deck gun. The curved metal structures at the stern were designed to protect the hydroplanes. Author’s collection

Technical Specifications of UB 115
Hull: double Surface Displacement: 519 tons Underwater Displacement: 651 tons
LBDH  55.30m x 5.80m x 3.68m x 8.25m  Props: 2 bronze Machinery: 550ps MAN/Vulkan diesels
Surfaced Speed: 13.3k  Underwater speed: 8k   Operational Range:  7,420 nautical miles at 6 knots
Submerged Range:: 55 nautical miles at 4k U/power: 394 ps electric motors providing 7.5 k Batteries: Lead/acid accumulators Fuel/Cap: 35-36 tons
Diving: Max Operational Depth of 50m (164′)  30 seconds to dive
Armament: 4 bow and 1 stern 50.04cm (19.7″)  torpedo tubes  Torpedoes:  10 Deck Gun: 1 x 105mm bow mounted   Ammo: 160 rounds of 105mm 
Complement: 3 officers and 31 ratings

After: The completed UB III boat, scourge of British coastal waters

The UB III class represented the zenith of German technological achievement, indeed the superb Type VII c class of the Second World War which saw service until the end of hostilities could be described as a modified UB III.

The streamlined bow of the UB III class. The net cutters were rarely used. Rarely have aesthetics and functionality been forged into such a deadly weapon

In mid-1916 as it now became clear that Jutland was unlikely to be repeated therefore there was to be no decisive North Sea battle feet action. As the imperative for Germany to mount a U-boat blockade of her own to counter the British block around the British coast, began to receive serious consideration, so attention became focused on the numbers of submarines needed to mount such a blockade (pre-war analysts calculated that 220 U-boats would be required for this enterprise). The U-bootwaffe underwent expansion from twenty-six boats in August 1914 to 120 boats by September 1916, growing to 180 boats by October 1918 (with significant numbers under construction). By October 1918 there were no fewer than five High Seas Fleet U-boat Flotillas and two Flanders Flotillas armed with UB and UC boats.

An expanded U-bootwaffe demanded a massive injection of manpower. The High Seas surface Fleet may have been redundant but possessed one saving grace in that it could usefully provide a pool of trained personnel for the U-boats. Post 1916 the best men were siphoned off from the surface warships of the High Seas Fleets to the U-boat wing. In direct consequence, 1917 is usually cited as the year in which the balance tipped away from a pre-war trained U-boat elite in favour of a force dominated by conscripts and reservists.

You can almost smell the diesel oil in this image. It encapsulates the old pre 1917 U-boot waffe. Tough, highly professional and dedicated (Author’s Collection)

By September 1918, when UB-115 sailed on her first and last patrol, the Germans were on the back foot on land and sea. The Allies had launched their August Picardy offensive and now the Germans were in retreat on the Western Front. The great sea blockade was biting hard at the German war effort. For some patriotism was no longer enough to persuade men to fight to the death when they knew their wives and children were starving at home. In 1917 the Germans had transported Lenin to Russia, bacillus-like in a sealed railway carriage but now the infection was finding fertile ground in Germany itself. In the messes of the High Seas Fleet at anchor in the Jade there was talk of workers councils and sometimes of revolution. The U-boat crews however proved immune to the siren call of Marxism. Yet this was no longer the professional U-bootwaffe of old.

The KDM had responded to the shortfall in officers by giving NCOs a level of responsibility that would have been unthinkable in the Royal Navy.
As reservists, many officers and men serving with the German merchant shipping lines were duly drafted into the U-bootwaffe expansion plans. Germany’s small but elite merchant navy tapped personnel possessing advanced navigational and wireless skills. The example of Bernard Haack provides a fascinating glimpse into the deployment of skilled reservists.

Haack, aged twenty-six in 1917, was acting Obersteuermann of the mine-layer UC-30. Haack was a Handelschiffsoffzier (HSO) who had served on Hamburg tramps importing coal from the Tyne, the Wear and the Tees since the age of fourteen. Having first earned his navigator’s ticket on a cargo vessel, Haack passed as Maat in 1910. Haack commenced a year-long stint of national service with the KDM in 1913, on the battleship Hannover as a Matrose. Following the outbreak of war, the KDM retained his services, rating Haack as Obermatrose in 1915. By the autumn all merchant seamen under forty possessing a Maat certifcate were summoned to Kiel for further training in navigation and pilotage. Because of his knowledge of the North East, Haack was rated as a Kriegslotse or ‘war pilot’ for that sector. In April 1916 he took part in an instructional patrol in the Helgoland-based U-76 to lay mines off the Farnes. Next came a bout of track-copying on the Wilhelmshaven depot ship, Lenne.

In August 1916 Bernard Haack was drafted (the term ‘appointed’ seems too delicate) to the U-bootwaffe, initially to UB-35 operating off the Forth. Haack found himself cycled backwards and forwards between mine-layers UC-32 (Breyer) and UC-31 (Stenzler) which regularly fouled the Tyne and Wear. Haack would later tell his British captors that he had served in four different mine-layers within the space of a year – evidence of a high level of unteroffziere mobility. Haack (now rated as Steuermannsmaat) soon found that KDM line officers regarded even highly skilled reservists as children of a distinctly lesser god. On 25 January 1917, Haack was captured (See UC-32 and the Children of Sorrow for details). During interrogation Haack lied to his captors on several counts and he was certainly prejudiced against the seeoffziere of UC-31 but evidence gleaned from other sources reinforces the view that reservists fared comparatively badly in the KDM (as they often did in the Royal Navy).

The rate of Obersteuermann also marks a fascinating departure from the Royal Navy model. Although it was possible for warrant officers to study for a ‘navigation ticket’ (King’s Regulations 1913, Part XIII), in practice the Royal Navy would have it considered unthinkable to hand responsibility for submarine navigation over to a petty officer but the KDM had no such qualms. Navigation, the calculation of an interception course and maintenance of trim calculations for the stowage of provisions were the responsibility of the most senior unteroffizier on the boat, the Obersteuermann. An Obersteuermann traditionally took third bridge watch, otherwise he spent his time in the control room bent over charts.

Like Haack, many mine-layer Obersteuermanner had formerly been merchant marine reservists. As previously mentioned, others were highly experienced Oberbootsmanner with a penchant for maths. This was the highest rank a seaman could aspire to. Rather ironically the only Obersteuermanner given the responsibility of command in the First World War were the men charged with sailing their boats over to Harwich for surrender in 1918.

At the beginning of 1918, largely through conscription, the U-bootwaffe was estimated to have an active strength of 11,400 men. By continuously cycling an estimated 15 per cent of unteroffiziere within each submarine crew, the Waffe was able to simultaneously expand while managing to retain a hard core of experienced personnel. As we have seen, veterans might be drafted to a boat for as little as three patrols, just enough time to pass on experience to a fledgling crew.

The picture that emerges of early First World War U-boat crew profile is that of a Seamanner (Seaman) branch drawn from German coastal states, contrasting with the Techniker (Engine Room/Technical) branch recruited from a much broader geographic area. The diagram below depicts the crew profile of UB 115. The crew is divided into three categories based on function, namely Offiziere (Officers), Techniker (Technical Staff) and Seemanner (Seamen). The Royal Navy operated a similar model, in its case divided between officers, seamen and engine room staff.

Crew members have been organised according to their status as Officers, Seamen or Technical specialists. Within the main divisions between Seemanner and Techniker the crews have been further sub-divided according to laufbahn. Officers are sub-divided into Seeoffziere and Ingenieur. With regard to the rest of the crew, several laufbahn are evident: Mechaniker, Matrose, Maschinist, Funker and Heizer. The British equivalents of these career tracks are given in brackets. Sadly it has not been possible to ascertain the ages of the men concerned.


Techniker (engine and motor room staff of UB-76 a UB III boat (Author’s collection)

UB 115 was reasonably well supplied with officers for a U-boat at this late stage in the war. Oberleutnant zur See Thomsen had the support of two line officers; the senior would be designated as IWO (First Officer). UB-115 was fortunate in also having had a qualified Engineering Officer (LI) appointed to the crew. By 1918 a U-boat engine room was likely to be in the hands of a capable Obermaschinist or an as-yet-unqualified Aspirant rather than a commissioned Ingenieur.

Warrant officers were given a special status within the KDM, known as unteroffizier mit portepee (sword knot). These senior petty-officers can be distinguished by the pre-fix ‘Ober’ such as Obermaschinist within the Techniker category. It will thus be seen that the highly skilled warrant officers belonged to both Seemanner and Techniker divisions. Note: Obermatrosen and Oberheizen did not belong to this exalted group, rather they were leading rates, classed as mannschaften or ratings. The role of the Oberbootsmann can be compared to that enjoyed by a Royal Navy coxswain. One important difference was that during an attack the Oberbootsmann did not oversee the hydroplane controls, rather his place was in the conning tower alongside the commander. Nor was the Oberbootsmann the most senior unteroffizier on the boat, as mentioned previously, that title belonged to the Obersteuermann.

Each boat would have its quota of unteroffizier ohne Portepee or junior petty officers. These might range from Obermaat, Bootsmannmaat (seamen petty officers), Funkmaaten (Telegraphists) to Mechaniker (Torpedo Mates) through to Machinisten (ERAs). In the Royal Navy, Torpedo petty officers and Telegraphists tended to be grouped under the seaman branch but in the U-bootwaffe, all specialists came under the Techniker umbrella. 

The various differences between Seemanner and Machinisten could be expressed in subtle ways. The seaman wore a star badge on his trade shoulder while engine room personnel sported a cogwheel motif. 

Seemanner: Matrosen and a Maat in the tube space of UB-76 (Author’s collection)

It was usual to find four trained gunners among the Matrosen. It is not clear whether the adoption of unrestricted submarine warfare led to a decrease in gunnery skills by 1918 but torpedoes were the primary armament for UB 115, with the Matrosen working under instruction from the Obermechanikersmaat. Two Funker (Telegraphists) per crew was the norm for U-boats of the period. The usual arrangement was for a qualified unteroffizier to be assisted by a rating. Radio and wireless was in its infancy. Hydrophone technology was making rapid advances and the Waffe would doubtless have wished to equip the boats with more men but faced a shortage of trained and qualifed Funker in both wars. Engines like the hydrophones needed constant attention. The more routine, mechanical tasks were carried out by the Heizen or stokers usually under Maschinist supervision. Boats usually carried seven to eight stokers.

In terms of training, corners were cut for all personnel but the seamen and stokers probably suffered most. Submarine training, particularly sea training, was cut alarmingly from three months to nil for seamen drafted from General Service. A salient point perhaps ought to be made at this juncture which is true of both world wars. While there is abundant evidence of men being conscripted to U-boats after 1917, there is no evidence that these men were compelled to serve against their will. The absolute interdependence of submariners means that a man who is serving in a boat against his will is a liability for all concerned. Mechanisms existed for drafting reluctant men from submarines back into General Service but these were rarely triggered. We can conclude that howsoever the men who fought the undersea war came to be serving in submarines in the first place, they remained because they wanted to remain. Michelsen in ‘U-bootskrieg’ estimated that 20 per cent of all non-commissioned personnel had received no submarine training whatsoever by 1918.

By 1918 expansion had forced the dilution of U-crews. Corners were being cut to an alarming degree. Sea training for Seemanner (seamen) and Heizen
(stokers) had been abolished altogether. The men simply learned on the job.

Conscription, training cuts and the recycling of key personnel all played their part in enabling the waffe to cope with manpower dilution resulting from unparalleled expansion. The service became dominated by men who may not have chosen to become U-boatmen, yet nevertheless felt compelled to do their duty in the highest traditions of the service. And they came out their corner fighting. One of the first out in 1918 was Hellmuth von Ruckteschell of the High Seas Fleet.

In January 1918, the V Flotille. boat UB-34 had taken up position off Tynemouth (having used up all torpedoes attacking shipping between Whitby and Sunderland) and the Commander logged convoy movements with professional interest. UB-34 had enjoyed a fruitful patrol after she left Helgoland on January 21. First she torpedoed and sank the steamer Hartley off Staithes on January 25. Later that morning UB-34 torpedoed another collier, Athos off Kettleness. The ship sank with the loss of two men.

SS Humber sailed alone and her crew paid the ultimate price. Humber was a regular on the Newcastle to Kings Lynn route.

By late afternoon von Ruckteschell had slammed a torpedo into the SS Humber off Whitburn, The ship sank with all hands. Later that day Oblt. von Ruckteschell had made a risky surface attack on the Dutch Folmina. The attack had failed due to a faulty torpedo gyro. UB-34 had been pursued by fast motor launches and forced to dive. The heavy depth-charge attack which followed caused slight damage.
All told, von Ruckteschell had fired five torpedoes in his January 1918 patrol and obtained four hits (Folmina did indeed sink). By 30 January UB-34 was back at base with the Commander crowned with laurels. With the exception of Athos, which had been escorted by a trawler, all the ships sunk had been sailing independently.

Humber: Tower Hill Memorial.
Three bodies later washed ashore but only one was identified.

Von Ruckteschell’s subsequent report made interesting reading and helped shape future convoy attacks in this sector. Von Ruckteschell recorded that there were plenty of trawler patrols within a ten mile radius of the the coast and that they were ‘generous with their depth-charges’ . In fact He had noted an inner cordon sanitaire of trawler patrols off the mouth of the Tyne but this inner picket line did not appear to be supplied with depth-charges. He observed that torpedo attacks were likely to be most favourable as the vessels were deploying into convoy position and the escorts had not yet formed a screen. The trawler escorts were augmented by fast motor boats. They worked well in conjunction with the trawlers. There was every indication the crews of both trawlers and motor boats were sharp and well trained. Above all, Von Ruckteschell warned of aircraft shadowing the convoys. A balloon or a Blackburn Kangaroo would spot a surfaced U-boat long before it was within range of a convoy screen. In the conclusion to his report he doubted whether there were sufficient large ships to justify the mounting risks in this sector. Indeed, on March 20, while at periscope depth and manoeuvering into position to attack a ship in convoy off Hartlepool, UB-34 was rammed and lost both periscopes. The U-boat was lucky to make it back to base.

Of course the imperative to attack the coal trade meant that High Seas Fleet U-boats had been prowling the coastal waters of the North East since the Spring of 1915 but now that newer, better boats had entered service, coupled with the fact that the Folkestone-Griz Nez Barrage was forcing the Flanders U-boats from the Channel, the Marinekorps boats were edging ever further North. The High Seas Fleet boats had regarded the North East coast as a training zone and now Bartenbach, the Flanders Commander considered the North East coast as a potentially useful training sector for operations in what were regarded as more arduous waters elsewhere. It was also a sector where crews suffering from nervous disorders could recover confidence and composure. By the Spring of 1918 both the High Seas Fleet boats (mainly the UC minelayers) and the Flanders boats were operating in the Northern sector of the North Sea. U-boat activities reached an intensity in 1918 and most of the ships sunk by enemy action off our coast were lost in this year.

The coastal stretch between Spurn and St Abb’s Head was routinely patrolled by U-boats. Flamborough Head and the sector between Whitby and Scarborough were favourite places to mount an ambush on vessels in the East Coast Channel (in 1918 to become known as the War Channel). Geographical features, headlands and distinctive harbours such as Hartlepool made useful navigational points. Longstone and Coquet Island were guarded by the Auxiliary Patrol but still the U-boats kept coming. How did the British respond ? The larger merchant ships were fitted with guns (of doubtful efficacy) manned by trained DAMS (Defensively armed merchant ships) gunners. With the German adoption of a policy of unrestricted submarine warfare, the U-boats were now making torpedo attacks from periscope depth, without warning, the guns were next to useless.

Adoption of the policy of unrestricted submarine warfare in February 1917 had seen British losses rise from 104,000 tons in January 1917 to an unsustainable 513,000 tons at the end of April. Losses in neutral vessels were equally disturbing, rocketing from 116,000 in January 1917 to 185,000 in April. Very many of these neutral losses were suffered either off the North East coast or on the traditional sailing route between Lindesnaes Light in Norway and Longstone Light on the Farne Islands. The British response was to introduce convoy for Scandinavian traffic. By 1918 the focus of the Scandinavian convoys was Methil in Fife but the ports of North East England dominated the coal trade. Escort provision had to be made for vessels joining or leaving the convoy for/from the Tees, the Wear and the Tyne. The result was the introduction of coastal convoys to dovetail with the ‘controlled sailings’ to Bergen.

The nature of these convoys changed with circumstances. The U-T convoys commenced on January 17, 1918. Vessels were shuttled between the anchorage in the River Humber and the Tyne. These were known as U-T convoys. U-T convoys picked up ships as they passed, ships joined at rear, whipped in by trawlers. The reverse passage was designated a T-U convoy. T-M convoys carried Scandinavian traffic, from the Tyne to Methil in Fife. From Methil the ships would be convoyed to Bergen roads. The Methil to Bergen convoys were coded O-Z at this stage of the war and H-Z when inbound. Scandinavian traffic, usually consisted of small to medium sized tramps bringing timber for pit props into the North East ports and returning with holds full of steam coal. There were tankers too and iron ore ships, these ships being particularly prized by KDM commanders.

Sailing times were altered as the year progressed to ensure the ships left their anchorage in daylight and preferably arrived off the Tyne or Methil during daylight hours. With shortening days in the Autumn the times of sailings was altered to ensure Northbound arrival during daylight hours, enabling the ships to enter the Tyne before nightfall. Southbound convoys were organised to allow the ships to pass Race Bank Channel during daylight. Although ship captains were ordered to adopt a zig-zagging course while passing through danger areas, this manouevre was often beyond them for a variety of reasons, ranging from the age of the vessels to the skills of the crews.

As the convoy picked its way through known trouble spots, it would be joined by local hydrophone equipped trawler hunting sections which would take up station on its seaward flank. While hydrophones were a useful tool to detect the sound of U-boat motors, their use was dependent upon the skills of the operator and above all the state of the sea. In rocky sectors such as Flamborough, the Farnes or Coquet Island, where the sea ‘boiled’ even in the hands of experienced men, hydrophones were of limited use. Skilled U-boat commanders such as von Rabenau studied the coastal inlets to make attacks in shallow leeward waters where they were not expected. Admiralty harnessed the technology of air power wherever it could. Balloons accompanied the convoys. Seaplanes based at South Shields and Blackburn Kangaroos at Seaton Carew, scouted ahead of the convoys looking for traces of U-boats. Of course the aircraft were useless in bad weather.

HMS Ouse (1904 vintage). On May 3, 1917 Ouse and HMS Bat opened fire on C 10 one of the Tyne defence submarines, mistaking her for a U-boat. A rating was killed. The resultant investigation only added to profound unease over the capabilities and training levels of reservist crews. The Destroyer later redeemed itself by helping to sink UC-70 and later played a role in the destruction of UB-115

Sailing times were also revised so that the crews of U-T destroyers arriving at the Tyne could carry on to Granton near Leith with the next T-M convoy, coal, then return to the Humber with next M-T and T-U convoys. This way the destroyers of the 7th Destroyer Flotilla (under Captain (D) R. Hornell based at Immingham) would be away from base for four days, allowing for four days rest on their return. By the Summer of 1918 T-M/M-T convoys were averaging thirty ships. The larger the convoy, the bigger the required escort. The largest recorded convoy, which sailed on October 15, 1918, consisted of seventy ships. This U-T convoy was escorted by four destroyers, one whaler and eleven armed trawlers.

The AMT Viola II (Admiralty No.6). Regular East Coast convoy escort. The doughty little ship served as a minesweeper at South Shields. Later she was attached to the East Coast Convoys and played a significant role in sinking UB-30 in August 1918 and later UB-115

The convoy escorts were permanently overstretched. There were simply too few vessels for the duties they were expected to perform. The larger convoys were escorted by four destroyers but many smaller convoys, particularly the ones peeling off the main convoy, bound for local ports, were lucky to muster a single destroyer and trawler escort.

Idealised image of an East coast convoy. The reality was that only the larger convoys could muster four destroyers. Most East coast convoys only had the benefit of one destroyer. The burden tended to fall on the Granton based armed trawlers and the fast motor launches. The motor launches were usually required to travel slow in keeping with the six to eight knots of the convoy and ensure that their engines did not interfere with the essential work of the hydrophone operators.

The 7th Flotilla escort destroyers, consisted largely of elderly ships of the ‘River Class’ commanded by reservist officers. The crews were also reservists with a leavening of conscripts. Captain (D) 7 raised frequent doubts as to the level of their training. These ancient vessels were subject to frequent engine breakdown and boiler problems. The 1899 vintage HMS Falcon (commanded by Herbert Lightoller RNR of Titanic fame) had been involved in a minor collision with an Admiralty trawler on April 1 but the elderly destroyer came apart at the seams and sank. On May 31, the mine-layer UC-75 had been rammed by the Admiralty Trawler Blaydonian while attempting to sneak under the convoy escort screen. The old escort destroyer HMS Fairy twice rammed the surfaced U-boat. UC-75 remained afloat but Fairy‘s bows opened like tinfoil. Although the U-boat ultimately sank, Fairy was also lost before she could reach the Humber. While most destroyers were equipped with wireless cabinets, in practice the convoys tended to rely upon visual signals as this was the only means of communication with the trawlers, motor launches and ships under escort.

HMS Star. Built by Palmer’s yard in 1896 and by 1918 a workhorse of the 7th Destroyer Flotilla guarding East coast convoys. She was slower than many of the ships she escorted.

The convoy system robbed the U-boats of their initiative regarding how, where and when to strike. Their only hope of success lay in lying at periscope depth, bows-on to an oncoming convoy. In order to adopt this position, the U-boat would have to surface to take advantage of its diesel engines to race ahead of the oncoming convoy and escorts. There was obviously a greater risk of being spotted by the convoy look-outs. The skill lay in gambling just how close the surface U-boat could creep within sight of the convoy screen without being seen. Sometimes the North East weather worked in favour of the attackers, sometimes it was on the side of the escort screen. Torpedoes were fired on the basis of speed, bearing and course. U-boat commanders did not just have to estimate these in relation to the target but with the introduction of convoy, also for the screening torpedo boats and trawlers. Penetrating an escort screen was not for the faint hearted as increasing numbers of U-boat crews were discovering. Either way the U-boats did not shrink from attacking coastal convoys. One remarkable case study will suffice to illustrate the point.

The trick was to get ahead of a ship or a convoy by using the speed of the diesel engines. The problem was that an aircraft or a balloon would spot a surfaced U-boat a mile off.

In June 1918, the Flanders U-boat, UB-88 (Kplt. Reinhard von Rabenau) had perhaps the most highly successful patrol off the North East coast against the convoy system. It is well worth relating the story in detail. The Flandern I boat UB-88 had left Zeebrugge on June 20 for a patrol between Flamborough Head and Sunderland. Von Rabenau was an experienced submarine commander with a track record of slipping through convoy escort screens. By early evening on June 22, UB-88 had crossed the North Sea to make landfall at Flamborough Head. The U-boat kept seaward of the War Channel and sailed North. Shortly before 19:00 a southbound convoy came into sight. Von Rabenau took the boat to periscope depth. He noted there were twenty ships with two armed trawlers on each flank. He estimated the speed of the convoy to be seven knots. Von Rabenau fixed his sights on a Swedish ship, the 1,624 ton Avance (Master: J.P. Hansen) at the rear of the convoy. Avance was en route to Hull, having earlier left an HZ convoy from Gothenburg to Methil. At 19:16 Von Rabenau fired. At 19:20 the torpedo detonated against Avance, blowing her stern, rudder and screw off. HMT Argo II moved in quickly and commenced rescuing the survivors. One man, a steward who had been in the stern, died from a crew of twenty. Von Rabenau moved North, still skirting the War Channel. By the following morning UB-88 was on the surface just off Saltwick Nab.

The War Channel of September 1918

The 1,706 ton SS London was sailing in a ten ship convoy, bound for Hull with a cargo of Dundee jute. The night of June 23 was fine and clear with a SE4 and a long swell. By this stage the convoy had increased to thirty ships.At 22.15 it was still daylight and the convoy was abreast of Whitby, when the look-outs spotted a torpedo break surface 200 yards off the starboard side. From the bridge the whistle was sounded, speed was increased to full and the helm was put hard to starboard.
The actions were too late to prevent the torpedo striking ten feet in front of the stern post on the waterline. The explosion that followed blew the stern away, leaving the upper deck hanging. London immediately took a heavy list to starboard and began to settle by the stern. The master, William Chapman, ordered the boats lowered and the crew of twenty-eight evacuated the ship on the trawlers Anzac and Jamieson.
UB-88 was subjected to nine depth charges following the attack on London. Nevertheless, Von Rabenau decided to take the risk of remaining in the Whitby sector. He moved seawards then surfaced UB-88 to charge batteries before returning to Runswick Bay later in the afternoon to await the next convoy. The next attack would be made from leeward.

UB-88: Note the painted eye on the bow, a Frisian Island tradition

On 24 June two convoys passed, one Northbound, the other Southbound. Zig-zagging was halted as the convoys passed in the War Channel.
There was a force seven NW wind blowing, a heavy sea from the NNE. Visibility was clear but conditions were too rough for the ships to post lookouts.  At 23.50 it was dark and no lights were showing.
Zig-zagging was about to commence when a ship, the 3,306 ton SS Moorlands was struck by a torpedo. Moorlands (Captain Hird) was on Government service carrying 5,800 tons of iron ore. Moorlands was hit on the No.1 hold on the starboard side, well below the water line. The ship sank in six minutes. Ten of the thirty-eight men on board were lost. The survivors were landed at Bridlington by the trawler, Lordship. The seventeen year old radio operator, one DAMS gunner, Pte. Hamilton of the RMLI were among those lost. The engine room staff included one man from Puerto Rico and three Muslim fireman/trimmers from India. All lost their lives in the cold waters of the North Sea.

The 4,482 ton African Transport (Master Thomas Tamblyn) had left the Tyne in convoy earlier on June 25, having loaded coal at Harton Staithes in South Shields, bound for Gibraltar. The fifteen ship strong convoy was making six knots on a SE course down the War Channel. African Transport was placed towards the middle, on the starboard side of the convoy, with four escort trawlers on the starboard beam bow, and a quarter destroyer ahead. At 21:05 with Whitby High Light coming into view, when a large explosion occurred on the starboard side.  African Transport was hit just below the water line in the area of the boiler room on the starboard side. The force of the explosion killed three of the engine room staff, blasted out the hull plates, crumpled the upper amidships decks concertina fashion, wrecking one of the starboard lifeboats.  The survivors were rescued by the convoy trawlers and landed at Tees Port. The escorts treated UB-88 to a barrage of sixteen depth-charges but von Rabenau was ultimately able to extricate his boat.

UB-88 ran out to sea in the hope that things would calm down in the next few days. In the early hours of June 29, the boat was on the surface off Scarborough Castle when the SS Sixty Six was spotted on a Southbound course. The ship was alone and not protected by convoy.
Sixty Six had left Middlesborough earlier with a cargo of cement. The ship was sailing South, keeping to the War Channel in foggy conditions. UB-88 was spotted at 02:15 was on the surface 500 yards abeam of her on the port side steering the same course. The helm was put hard to starboard to bring the submarine astern, but within a few minutes a torpedo struck the vessel amidships. The explosion was so intense that the ship was shattered and sank immediately, the survivors which included two engineers, a fireman and a couple of DAMS gunners were hurled into the water but the Master, Mr Rounce and five others died in the ship.  Von Rabenau’s rampage was not quite over. Once again he took UB-88 out to sea to charge batteries and load torpedoes.

Southbound T-U convoy. Larger, more valuable ships tended to be placed at the centre of a convoy making them more difficult for a U-boat to torpedo

That evening the sea was calm and conditions were fine and clear with a smooth sea. A Southbound convoy was in the War Channel approaching Whitby. One of these ships was the collier Herdis, occupying the port side position towards the stern of the convoy and sailing at six knots. At 22:27 a periscope was seen some 2,400 yards off the port beam. Gun fire was opened on it but no hit recorded and the submarine dived, she was heading in the same direction as the ship and was never seen again
At 22.50 a torpedo struck Herdis the on the port side abreast of the main mast and the ship commenced to sink by the stern rapidly. As soon as the vessel was struck the chief officer jumped overboard without receiving any orders to do so. The nineteen strong crew evacuated the ship in the starboard lifeboat and were picked up within 20 minutes by the escort trawler Thebau and landed at Grimsby. By this stage von Rabenau and his crew decided to alter course for home. Ten torpedoes had been fired. Six had resulted in explosions though the crew of UB-88 did not know the extent of their success.

In fact June, with a loss of ten merchant ships marked the high water mark for German attacks on the East Coast convoys. From January 17, 1918 to November 12, 1918 a total of twenty-seven ships were lost in convoy as a direct result of enemy attack, almost all to U-boats. During this period over six thousand ships sailed in T-U and U-T convoys. A success by any standards. Although they could not stop the U-boats from attacking the convoys, they could make life hell for them if they tried.

The word ‘Wasserbomb‘ is always found side by side with ‘Konvoi’ in Kriegestagebuchen (KTBs) of this period. As the U-boat crews dealt out death and destruction, so they now faced a terrifying retribution from the depth-charge racks of the destroyers and trawlers. U-boat crews serving in UB-64, UB-21 and UB-40 all suffered harrowing depth charge attacks that summer attacking East coast convoys. One of the Marinekorps boats, UB-78 new to this sector, sank Polleon in convoy off Tynemouth on March 22. The twenty-five depth charges which followed caused little damage but the escorts caught the U-boat in an explosive net. Pursuit continued for ninety minutes and fragments of the net were later recovered from the conning tower. Several commanders are believed to have suffered mental breakdowns.

Then the U-boats began to suffer losses on the East coast. First in May, UC-75 was lost attacking a convoy off the Yorkshire coast. In July UB-110 was lost off the Tees, again in the course of attacking a convoy (as this event is a minor epic in itself it will be covered elsewhere). The boat was raised and speculation continues that useful charts may have been recovered which led to the destruction of several more U-boats. UB-107 sank in mysterious circumstances off Flamborough Head. UB-30 then UC-70 were sunk off Whitby at the end of August. Now it was the turn of UB-115 to venture into this cauldron.

Oblt. Reinhard Thomsen, SMS U-boot UB-115

UB 115 left Zeebrugge on September 18, 1918 for a routine working up patrol that would take her to the North East coast.  This was not just the Boat’s first patrol. It was 27 year old Oblt. Reinhard Thomsen’s first patrol as Commander. Onboard was an officer under instruction, Kplt. Alfred Koellmann, formerly of the cruiser Nurnburg. Although Koellmann outranked Thomsen, his role on this patrol was simply to watch and learn.

Submarines were poor sea-keepers and just crossing the North Sea was often an ordeal in itself as Willi Schlichting describes:
Time to relieve the watch. Complete with oilskins and tarred cape, with a sou’wester on my head, I stand ready for the moment to clamber up from the control room up to the bridge. She is rolling from side to side like an old sea cow. My mate Hein is certain that my oilskins will not hold out for long, but we shall see. Now, in a brief moment between two oncoming waves I am through the hatch, greeted by grunts from the relieved watch, ‘About sodding time too!’ I am met by spray from a breaking wave which bursts over me the moment I steady myself on the bridge. ‘Damnably cold weather,’ murmurs the officer. Day is turning into night and we are caught in a North Sea hissing, swirling witches cauldron. Down she goes. Up she rises like some berserk whale. We have to clutch the conning tower rail so as not to be washed overboard. Hailstones bombard us like artillery, stinging our faces and somehow penetrating our oilskins. Hein was right. I was frozen to the bone and frankly did not care whether I lived or died. Everyone else threw up but me. I was determined that Neptune would have no tribute from this sailor.

A North Sea crossing was frequently a wild ride

Even the longest watch comes to an end. My relief appeared and I stumbled blindly down the hatch and onto the back of the officer of the watch who was standing below. I lurched along to my bunk. A pallid face peeped out from one of the bunks and retched and retched. At this sight my own stomach began to turn again and I could barely contain myself. The atmosphere below was beyond description. The damp, warm, stifling air made me feel more nauseous than ever. Before I lay down I swallowed a little tea and glanced into the engine room. An appalling burst of heat flung me backwards. The thermometer read 45 degrees Celsius. The men were standing over their engines in the minimum of clothing and their drawn, gaunt faces smeared with oil looked like skulls. The air was unbelievable.

The thudding diesel engines had exhausted such air as could be pumped in through the ventilators. Hot eddies of vapour hovered over the engines and gradually drifted to the other compartments; the men were continually mopping their foreheads and now and again one of them would sip the revolting lukewarm tea which, like all the food and drink on the boat, tasted strongly of oil. I fed from this oil-reeking domain and tried to get some sleep in my bunk. Earlier the cold had been the cause of my discomfort. Now it was the foul air that made breathing a torture and would not let me sleep. Sweat broke from all my pores. I had tried to wedge myself in every conceivable position so as not to be hurled out by a sudden heave of the boat. Those five hours of ‘rest’ seemed more like eternal torment. The summons to ‘Stand By to relieve the watch’ came almost as a relief. Exhausted, shattered, without a wink of sleep, I hoisted myself from the bunk. As I made my way through to my post in the control room, I passed one of the old hands heartily tucking in to a plate of beans and bacon. To my poor sea sick belly, this was like a red rag to a bull. I couldn’t help myself. I spewed up all over him’

Normal routine upon approaching the enemy coast was to remain on the surface in darkness to charge batteries, then dive to periscope depth at daybreak.

UB-115 made landfall at Flamborough Head on or around September 20. The boat headed Northwards. Nothing further is known until September 21. SS Staithes (Captain Radford) was a 336 ton steamer which regularly ploughed between Port Mulgrave and the Tees or Tyne.

The doomed Staithes

Staithes was Northbound for the Tyne and sailing alone when UB-115 struck her with a torpedo. It is impossible to give details because there were no survivors.

The masts of little Staithes are said to have projected from the sea off Hendon Rock, Sunderland for many months.

Tower Hill Memorial. The ship’s Engineer Charles Wyatt also died.

By September 29, UB-115 was operating off Newbiggin. AMT’s from Blyth investigated a submarine sighting at 10:16 but found no trace. At 13.29 the crew of the East Fortune based airship R29 (Major G. Thomas), scouting ahead of a T-M convoy, sighted an oil slick on the surface.

R20 One of R29’s sisters. North Berwick Law in view

R29 then dropped two 230-pound bombs to indicate the location to Ouse and Star, the destroyers escorting the convoy. Ouse did not locate the oil slick until R29 had dropped another bomb followed by a calcium flare. This time the two destroyers proceeded to drop seven depth charges set at 50, 100 and 200 feet; trawlers, Beatrice, Florio, Bombardier, Stronsay and Viola joined the hunt and dropped ten more charges.

Northbound TM convoy executing a zig-zag

Oil and air began to come up in considerable quantities, though the air bubbles were quite small. Evidently the U-boats hull was still fairly tight. At 14:00 the U-boat started her motors but soon stopped them again after the trawlers, listening with hydrophones, dropped twelve more charges. An hour later the U-boat motors started again. Two more depth charges brought up oil. By this stage UB-115 was likely so badly damaged as to be unable to reach the surface. Between 16:00 and 18:25 the U-boat ran her motors constantly in spite of the depth charges occasionally dropped. Oil came up all night, and two days later sweepers located an obstruction from which oil was still rising.

The destruction of UB-115 as photographed from R29, 29.9.1918. The trawler is HMT Bombardier. The vessels are depth-charging different positions, presumably to cut off retreat. Note oil slicks on surfce

Log of HMS Star
AM Sun 29 Sept – Berthed alongside collier Ryhope at Jarrow
12.00 – Cruising stations starboard quarter of convoy escorting T-M convoy. Proceeding up war channel – zig-zagging.
1.50 – Rigid airship observed to drop bomb to eastward.
1.51 – Full speed closed spot.

1.54 – Commenced dropping depth charge – dropped 5 in quick succession
2.32 – Full speed. Dropped 6th depth charge on spot indicated by airship. Oil seen coming to surface, also air bubbles.
2.50 – Full speed.
2.51 – Dropped 7th depth charge on oil patch. Stopped to collect oil and examine vicinity
4.50 – Rejoined convoy’

None can tell how long the conscript crew of UB-115 lingered, hopelessly. The sobering evidence indicates that these men did not die quickly. At any rateUB-115 was the last U-boat to make a patrol from Zeebrugge, In a matter of weeks it was all over.

The Crew of UB-115

Bansemer RMts.Lob HermanMts.
Becker RichardMasch.MtMebus ErwinMasch.Mt.
Benz GeorgMts.Mehne RichardFt.
Bonn ArthurLt. s.Z.Moss Hans
Bonningsen HHzr.Muller FranzHzr.
BuddenhagenOb. Mts.Nuss PaulMasch.Mt.
Borner MaxMasch.Mt.Peters HansOb.Mt.
Dmock WillyOb. Hzr.Post ArthurMasch.Mt.
Eckert GOb.Masch.Mt.
Eisermann ROb.Masch.Mt.Preising HermanBt.Mn.
Grunau FritzMasch. Mt.Ronkel AugustHzr.
Hansel KurtFt.Mt.Rosenbusch RicardHzr.
Hausich KarlMts.Ruck WaldemarMts.
Heinze Johann Hzr. Schauber MichaelOb.Hzr.
Hosel LudwigMts.Schieweg ROb.Masch. Anw.
Knorr ChristianMts.Schroth WMts.

Koellmann Alfred
Kplt.Tegge KMasch. Anw.
Kratsius RichardSt.Mn.Thomsen ReinholdOblt.
Herbhagen C
Koppe OttoMts.WilkensMn.Ing.

In the 1920s a journalist claimed that a chart found in the salvaged UB-110 provided information on U-boat bottoming out zones in North East coastal waters lead directly to the destruction of an unnamed U-boat. The log of HMS Star and RNAS records makes it clear that this cannot refer to UB-115, though this has been claimed. The U-boat was detected by the pure chance of discovering an oil slick. As for the alleged chart, it has yet to be found in the National Archives. It must be assumed that UB-115 was lying in wait in the War Channel in readiness to attack the convoy. Had the crew been aware of the fuel leak, the normal procedure would have been to motor out to sea as far as possible at periscope depth, then surface to effect repairs to the seam and charge batteries.

It had been a day of congratulations for the Auxiliary Patrol and the 7th Destroyer Flotilla. Lt. Ronald Stuart RNR of HMS Star was awarded a DSO and Lt. Lilley a DSC, gazetted on March 24, 1919:
the ship..was handled in a most creditable and satisfactory manner”…. and co-operated with the Air Force in a most excellent and zealous manner.Their Lordships’ appreciation expressed‘.
On the occasion of the destruction of the enemy submarine UB-115, on the 29th September, 1918, Lt. Lilley was Officer of the Watch, and showed an alertness to duty in the prompt alteration of helm and increasing of speed to clear the position over which Airship R.29 had released a bomb, and so enabling a successful depth charge attack to be made by “Star”.

Lt Walter Bird RNR of HMS Star received a bar to his DSC with the following accreditation, Captain (D) 7th Destroyer Flotilla, described Lieutenant Bird as “indefatigable in his efforts and one of the most successful officers in anti-submarine warfare that I have ever had the honour to command.”

Lt. Peek RNR of HMT Bombardier was also awarded a bar to his DSC.
Captain and Senior Naval Officer Tyne stating that he “displayed great ability and intelligence in organising the vessels of his group … and contributed largely to the complete destruction of the enemy.”

Remarkably one reminder of that day in late September 1918 is still with us, though perhaps not for long. The Trawler Viola II survived both world wars to end up at South Georgia as a sealing vessel.

Viola II laid up and crumbling away at Grytviken, South Georgia

The heroic little ship is now the subject of a drive to bring her back to Hull before she is too far gone to save. A book has been written about her exploits and series of commemorative stamps issued.

Viola II depth-charging UB-115

Time, disrespect and circumstance have been more unkind to the remains of UB-115. The wreck lies off Cresswell, a short distance to the North West of the wreck of another submarine, HMS Unity. In 1973 the wreck was reported to be upright, covered in nets and lying in a depth of 44 m. First came the sports divers followed by commercial salvage men in 1995. The latter demonstrated their regard for maritime War Graves by quite literally blowing UB-115 apart with explosives then systematically ripping it open. Despite widespread local knowledge of what was afoot, the authorities did not act to protect this War Grave. Afterwards sports divers returned like carrion to pick away at what little remained.

Thanks to the depredations of commercial salvagers and sports divers little remains of UB-115

The wreck is now unintelligible raft of scrap with a few plates scattered either side of a half hidden keel sunk into the sand. Forensic examination of the wreck is impossible.

During 1918 the battle for the East coast was quite finely poised with both sides adapting their tactics to changing circumstances and harnessing the advantages of technical innovation. The Germans relied above all on their new class of U-boat, the UB III. These U-boats were highly successful in skilled hands and the modified design survived as the Type VII U-boat of the Second World War. It was all too little too late. The Germans never did have sufficient U-boats to blockade the British Isles and they failed to take advantage of Britain’s dilatory initial response to submarine warfare in the first three years of the War. As for the British, the reluctant rediscovery of convoy, allied to technological innovation in terms of depth charges, hydrophones and air support, all played their role in keeping the U-boats at bay. As regards the crew of UB-115, it was simply unlucky. In common with so many submariners before and since, the boat was simply in the wrong place at the wrong time.

We can never be certain what contribution, if any, the relative inexperience of many of the late war U-boat crews may have had to operational losses; there does not appear to have been any serious effect upon either morale – or performance – despite what is written in the ‘Room 40 History’. By the time that UB-115 set out on her first and last patrol it must have been obvious that the War was over and that Germany had lost. The High Seas Fleet had mutinied. Revolution was in the air. Despite sustaining a 51 per cent casualty rate by 1918 (5,132 died, 729 were captured) unlike the rest of the KDM, the U-bootwaffe remained a viable fighting force by November 1918. Moreover it had evolved into a distinct organisation animated by its own identity and inspired by its peculiar mythology, the flavour of which can be found in these post-war reminiscences: Oberbootsmaan Oscar Wehner:

Only a sense of duty kept us going for love of our people, helping overcome our very real fears, and only the thought that we could help Germany in those desperate years gave us strength for the ordeal. Above all it was mateship that kept us going out on patrols. Never mind what those corrupt politicians and military idiots did, we kept going for each other’.

Karl Neureuther summed up the ‘U-boat spirit’ with this address to a gathering of old submarine comrades in Munich in 1921:

‘What kept us going when all seemed lost? The profound sense of loyalty within a small group of men bound together by a common purpose. It was this community of labour, this absolute interdependence which fused all sections of a U-crew into an indivisible whole. It wasn’t just me, the commander, who held the destiny of the crew in my keeping. No, even the most humble seaman or stoker held the fate of the entire crew in his own hands. Submariners of all nations know that moment when a man’s life means nothing; we know those seconds when life hangs by a thread and survival is nothing more than a dubious ‘maybe’. We know what it means when a man puts his life into the hands of his superiors, or those under his command, his brothers in arms – a little band of men isolated in enemy waters, far away from home. Looking back on it now, the experience taught us one thing which we should never forget, that in future men ought only to sacrifice themselves for what is worthy of that sacrifice’.

On the last count he was to be very disappointed.

ADM 137/2964. ADM 53/61347, AIR 1/420/15/246/4, T1022, Roll 42, PG61870

Silent Warriors Vol 1, German Submarine Warfare 1914-18, Koerver, Room 40 History of Submarine Warfare, Handelskrieg mit U-booten, Arno Spinder, Technical History Series: East Coast Convoy

© P Armstrong