U57 class (1916)

Germany: SM U57 to U-62, 99 to 104 (1916-17)

The Mobilisation U57 class U-Boats were the first incursion by A.G. Weser, Bremen, into the usual realm of Germaniawerft and Kaiserliches Werft shipyards.
The need for more U-Boote was pressing and to bolster the numbers, a series of twelve submersibles were ordered, based on the U41 and U27 for the U99 sub-group.
They had a rounded prow, and the same well separated deck and double hull, MAN diesels and two 8.8 cm guns, although this was changed later in the war.
This class was improved during construction (U60 and U99), with better diving time and better diesels, better range and speed, and up to twelve torpedoes.
As previous classes, they had quite a collective tally. The most successful was the lead boat U57 (55 kills). In all, they claimed around 350 ships sunk, damaged around 30 and a dozen warships including an armoured cruiser. But almost half of these subs were lost in action as well. #kaiserlichesmarine #ww1 #agweser #hamburg #rmsolympic

Design of the U57 class:

About AG Weser efforts for U-Boote

Essentially the U57 class was the product of a newly “recruiter” shipyard, so far unaccustomed to submarines. A.G. “Weser” was founded in 1872 as the successor to the iron foundry and mechanical engineering company Waltjen & Leonhard founded itself in 1843 by Johann Carsten Heinrich Waltjen and Heinrich Leonhardt, at the time on the outskirts of Bremen, Stephanikirchenweide (now Überseestadt district). They produced bridges and cranes, iron lock gates, steam boilers or steam engines, and factory equipment. In 1847 they built their first ship, the iron sidewheel steamer and tug Roland (hull number 1). In August 1914 it was clear that the war would drag all yards to help the war effort and AG Bremen was asked to participate in the U-Boote production, something that was confirmed after early successes. BUt AG Weser differed from the two state yards usually involved in submarine construction, as not only it was a private company, but due to its reputation for politicised workers and frequent strikes.
Armaments production led indeed to an intensification of work and restrictions of labour rights, which locally led to new conflicts. Between 1916 and 1918 just as in many other armaments factories, political strikes started in sympathy with Karl Liebknecht in June 1916 but soon the “Bremen Left Radicals” group gained greater influence among shipyard workers and its culminated in November 1918 with the formation of a workers’ council and active participation in the November Revolution in Germany.

As for what U-Boat types the shipyard produced, AG Weser would deliver relatively few large submarines. The next classes would be the U131 to U-134 of the U-127 large oceanic submarines (Ms boats 1918), but none were completed as the war ended just as the U-219 to U-224 of the U213 series (1918), however soon the yard built more actively light and cheaper submarines of the UB-1, UB-2 and UB-3 types, in fact dozens of these, taking the bulk of their manufacturing in complement to Germaniawerft, Blohm & Voss and Vulkan, Hamburg. Same for the UC-1, UC-2 and UC-3 albeit none of the latter were completed.

Development

Now on the purely technical level, the U57 class was a mix between several types already well known and mastered from Danzig and Germaniawerft, and relatively conservative compared to the U43 class and its completely rounded hull. Instead, the Weser design took the path of the Germaniawerft boats with well separated outer hull deck and lower outer hull, with a flattened upper section. The conning tower was a mixture of both designs. The U57 class were ordered on 6 October 1914, when enough experience had been gained already in these large types, and amazing successes only spurred more orders proposed to more shipyards across Germany. AG Weser engineers however tried to reach better performances overall, notably improved the hull for greater diving times.

Hull and general design

Plan and cutaway 2-view reconstructed by the RN study of a captured sub, Ordnance survey dated May 1918. src
The U57 to U62 (1st series) from Bremen were a bit larger than their inspiration from Kaiserliches Werft, displacing 786 t (774 long tons) surfaced and 956 t (941 long tons) submerged for a total of 1104 tonnes, fully loaded and submerged. This was for an overall length of 67.00 m (219 ft 10 in) and a pressure hull that was 54.22 m (177 ft 11 in) long inside. The beam extended to 6.32 m (20 ft 9 in) for the outer hull and 4.05 m (13 ft 3 in) for the pressure hull. The draught was 3.79 m (12 ft 5 in) and total height from the keel to the top of the conning tower was 8.05 m (26 ft 5 in).

1:8 Yard Model of the U57 src

Design-wise, she had a rounded prow, instead of the classic straight one, a new discovery of pool tests with models. This new rounded prow was largely adopted as it created less turbulences and thus, underwater drag at speed. The prow was composed also of a rounded chin, with a straight section at the waterline. To improve sea keeping, the deck was raised substantially forward above the torpedo tubes. The design was relatively wide, with a ratio way more pronounced than slender WW2 U-Boats, and the outer hull, flattened on top, a classic feature of more ancient U-Boats unlike Danzig’s revolutionary U43 class, met the flat sides raised deck with gentle slopes and cutouts water scoops running all the war to the tail.

The double hull was composed of 13 separate compartments, with two ballast tanks fore and aft (6 in all), with two more amidship, two regular tanks, and four oil tanks. The pressure hull was of course not a straight tube. It was narrow forward, meeting the pair of torpedo tubes, and aft of them were a pair of 1.3-1.4t torpedo compensating and aft, a 2.13t trimming tank and a 1.36t drinking water tank, all under the deck. The dive planes were located below the waterline and leaf-shape, with their axis directly below the forward tubes.

Next was the second pressure hull compartment with the commander’s cabin and officer’s , warrant officers mess, sanitaries and the galley plus a 600 kgs distilled water tank next to these.
The control room was next, behind a concave bulkhead, with three periscopes (a novelty, the norm was two), including one smaller backup periscope in front of the CT the two others were internal, passing though the conning towing bell protruding from the pressure hull above, with a tall and slender navigation periscope and an attack one. There was a tank of drinking wter below deck.
Then came a convex bulkhead separating the Control Room from the larger engine room. This was the beamiest part of the pressure hull, containing the tw diesels side by side, close to oil fuel ready use tanks and distilled water tanks aside, because below deck were located the battery. A thin separation led aft to the electric engines and motor room, and the aft bulkhead separating the machinery room from the aft torpedo room, which narrowed up. The shafts were supported on small struts. The design of the outer CT was conventional, with a “spine” running at the base of the CT, then a bridge and small hatch to enter the CT bell. The crew was 36 strong including officers, 4 or 5, and there was a small boat encased under deck.

Power plant of the U51 class

U57 in Cherbourg. She was tested by the Marine Nationale before being BU. Note the tail’s shape and anti-collision bars.
The U57 class followed the trend of previous U-Boats, sporting two MAN diesels, two-stroke 6-cylinder rated for a total of 1,800 PS (1,324 kW; 1,775 shp.) surfaced and completed by two Siemens-Schuckertwerke 1,200 PS (883 kW; 1,184 shp) submerged on 2 shafts with three bladed propellers.
Top speed, respectively, was 14.7 knots (27.2 km/h; 16.9 mph) surfaced and 8.4 knots (15.6 km/h; 9.7 mph) submerged.
Note: It was not great for a first try from Bremen AG on the Weser. But that was for the first batch only, U57 to U62. To compare, the U51 class was capable of 17.1 knots surfaced and 9 knots underwater.

Range was also not stellar, with a total of 7,730 nmi (14,320 km; 8,900 mi) at 8 knots (15 km/h; 9.2 mph) surfaced and 55 nmi (102 km; 63 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged. To compare, the U51 class again was able to cross 9000 nautical miles at 8 knots, and cross the Atlantic (one did a trip to the US before the Deutschland was operational). Instead, the U57 class wisely stayed around the British Isles. Test depth was the same as other boats, 50 m (164 ft 1 in).
However, this was blatantly clear for AG Weser, which reworked the design, leading to the U99 sub-class.
The latter indeed had more powerful 4-stroke diesels for 16.5 knots surfaced. Oil storage also went to 129 tonnes versus 119 tonnes on the U57 class. This brought heir range to 8600 nm., but down to 49 nm underwater at the speeds above. Diving time was constant at 49 to 52 seconds which was quite good for the time, however.

Armament

On this topic, the U57 class was rather conservative, with the classic two pairs of 50 cm tubes fore and aft (19.7 inches) and seven torpedoes in reserve, including the ones already preloaded (so three spare). Originally they were fitted with two 8.8 cm main guns, one on either side of the deck on sponsoned platforms fore and aft of the conning tower. Later a 10.5 cm SK L/45 was installed as standard, either alone or forward, with a 8.8cm SK L/30 remaining aft.

Torpedo Tubes

Germany started by equipping its torpedo boats and early U-Boats of the 1890s with the 35cm (14 in) C35/91 and C35/91GA, then 45cm (17.7 in) C45/91 Br, C45/91S, C/03 and C/03 D were reserved for surface ships, and the C/06 and C/06 D for U-Boats from U3 onwards. They stayed standard before the introduction of the 50 cm. The initial model was reserved for surface ships. This was the (19.7″) G/6 and G/6D which used either the Decahydronaphthalene (Decalin) or Kerosene Wet-Heater.
From U23 onwards, all U-Boats came equipped with the new and famous G7 (entering service in 1913), repeated by the U27 class and follow-up classes. Still, there were important stocks of G/6, mostly now used for training or tests. The Kerosene powered G/6D was considered too “temperamental” for submarine use indeed. The G/6 was developed from 1908 and entered service in 1911. The Royal Navy was slower on this chapter, only introducing the 21″ (53.3 cm) Marks II, II* and II** for submarine use from 1914 onwards. The four 500 mm (19.7 inches) torpedo tubes could be reloaded from above via the larger hatches going through the outer upper hull.

G7 Torpedo

The G7 was designed in 1910 and entered service in 1913. Originally designed for surface ships, but in 1917 it started to be used on U-boats.
Specs:
Weight: 3,009 lbs. (1,365 kg)
Overall Length: 276 in (7,020 m)
Explosive Charge: 430 lbs. (195 kg) Hexanide warhead
Range/Speed settings: 4,370 yards (4,000 m)/37 knots and 10,170 yards (9,300 m)/27 knots
Power: Decahydronaphthalene (Decalin) Wet-Heater

8.8 cm Schnelladekanone Länge 30 naval deck gun

For the U19 onwards, the classic 3,7 cm or 5cm deck guns were ditched out and as U19 was considered large and stable enough to have a larger gun installed and a single 88mm 27 calibre TK L/30 C/08 deck gun was installed forward. For this the deck was reinforced but no sponsons extensions appeared seemingly on photos.

In 1916, after captains reported this gun still weak, notably to scuttle a boarded ship or engage an armed trawler. They spent way too much time sinking their prey, which called for enemy reinforcements. Thus, all four boats had a second 8,8 cm deck gun installed aft, making two. U19 was the first U-Boat class with two guns, fore and aft. This was repeated for the U23 and U27 classes in wartime. U30 exchanged both guns for a single 10.5 cm/43 TK L/45 C/16 deck gun in 1918. The 8.8 cm became the standard go-to gun for all U-Boats built afterwards, until the U87 class (launched 1916), generally two for oceanic boats, one for minelayers and for later coastal subs. They accounted for many of their preys.

The 8.8 cm SK L/30 gun used the Krupp horizontal sliding block, or “wedge” and the submarine deck version was on either a retractable or fixed pivot mount. The Krupp mount retracted vertically through a hatch, and the Erhardt version folded down onto the ship’s deck. They avoided underwater drag and turbulences. It seems U19 class had the Ubts.L of the second type.
The 8.8 cm SK L/30 was a widely used naval gun on World War I pre-dreadnoughts, cruisers, coastal defence ships, avisos, submarines and torpedo boats in both casemates and turrets as well.
This calibre became so ubiquitous in the German Navy it was still a favourite for WW2 U-Boats as well starting with the Type VII. Read more The U57 class carried 276 rounds for both guns originally.

Specs 8.8 cm SK L/30 on Ubts.L mount

Weight: 644 kilograms (1,420 lb)
Overall length: 2.64 meters (8 ft 8 in).
Breech: Krupp horizontal sliding block
Shell: fixed 7 kg (15 lb) cal 88 mm (3.5 in)
Elevation: -10° to +30°
Rate of fire: 15 RPM
Muzzle velocity: 590 m/s (1,900 ft/s)
Maximum firing range: 7,3 km (8,000 yd) at 20° or 10,5 km (11,480 yards) at 30°

10.5 cm SK L/45 naval gun (1916)

In late 1917 and 1918, some boats traded their two 8,8cm deck guns (or single one) for a single 105mm deck gun with 300 rounds. The crew rose to 46-48 men less four officers, now with a proper gunnery officer.
Built by Meddinghaus, this heavy deck gun was designed specially for deck use, low, with many sensible elements protected from corrosion.

Specs 10.5 cm SK L/45

1,450 kg (3,200 lb), 4.725 m (15 ft 6.0 in), 6.8 mm (0.27 in) wide.
Shell 10.5 cm (4.1 in) 25.5 kg (56 lb) fixed Brass Casing 17.4 kg (38 lb)
Breech: Horizontal sliding-block, MPL C/06: -10° to +30° mount
Rate of fire: 15 RPM
Muzzle velocity 710 m/s (2,300 ft/s)
Effective range 12,700 m (41,700 ft) at 30°

⚙ U57 specifications
Displacement	786 t surfaced, 956 t submerged
Dimensions	67 x 6.32 x 3.79 (219 ft 10 in x 20 ft 9 in x 12 ft 5 in)
Propulsion	2 shafts MAN diesels 1,800 PS surfaced, 2× AEG EM 1,200 PS submerged
Speed	14.7 knots surfaced, 8.4 knots submerged
Range	7,730 nmi at 8 knots surfaced, 55 nmi at 5 knots submerged
Armament	4× 50cm TTs (2 bow, 2 stern, 7 torpedoes), 2x 8.8 cm SK L/30 gun
Max depth	50 m (160 ft)
Crew	5 officers + 31 men

U99 sub-class

The first upgrade in the U57 class was U60 which already had a greater fuel oil capacity, from 129 tonnes and the company addressed both the speed and range issues, as they were equipped with more powerful MAN diesels 4-strokes for 2400 bhp for 16.4 knots, and a range of 8600 nm and underwater 49 nm.
The symbolic U99 sub-class from Weser AG was different in which it was directly derived and based on the U27 type from Danzig NyD, albeit much larger. They were ordered later in 1915 and launched in 1917. Diving time went from 52 to 49 seconds, the best of any U-Boats of that size so far.
The U99 class had a slightly smaller hull at 750/952 tonnes (750/952 long tons). The pressure hull measured 54.02 m (177 ft 3 in) overall for 4.05 m (13 ft 3 in) in beam. Total height was 8.25 m (27 ft 1 in). The general shape of the conning tower was also altered in some ways. Performances in speed and range were increased.

⚙ U99 specifications
Displacement	750 t surfaced, 952 t submerged
Dimensions	67.60 x 6.32 x 3.65 m (221 ft 9 in x 20 ft 9 in x 12 ft)
Propulsion	2 shafts MAN diesels 2,400 PS surfaced, 2× AEG EM 1,200 PS submerged
Speed	16.5 knots surfaced, 8.8 kts underwater
Range	10,100 nmi (18,700 km) at 8 kts surfaced, 45 nmi (83 km) at 5 knots submerged
Armament	As U51 class

Career of the U57 class

U57

U 57 was ordered from A.G. Weser, Bremen under Werk 212 on 6 October 1914, laid down on 25 August 1915, launched on 29 April 1916 and commissioned on 6 July for 3.924.000 Mark. Until 19 Dec 1917 she was under command of Kptlt. Carl-Siegfried Ritter von Georg (awarded Pour le Mérite) then until 6 Mar 1918 by Oblt. Günther Sperling and, until 11 Nov 1918, Oblt. (R) Walter Stein. In all she performed 7 patrols, all between 7 Jul 1916 and the end of the war as part of the II Flotilla, sinkling 55 ships for 91,606 GRT, plus 7 damaged (15,735 tons) and the 1,250 tons sloop HMS Genista off the west coast of Ireland. All 73 crew members were killed. Three days after, she encountered the 10,320 GRT Rowanmore, her largest prize. This mixed cargo and liner was en route from Baltimore to Liverpool. Sunk by torpedo, there were no casualties. On 24 Nov. 1918 she surrendered to France and was tested, then BU at Cherbourg in 1921.

U58

U58 was ordered on 6 October 1914 at AG Weser, Yard number 213, laid down on 8 June 1915 and launched on 31 May 1916. She was commissioned on 9 August 1916. She operated with II Flotilla from 16 October 1916 to 17 November 1917 under Kptlt. Kurt Wippern from 9 August 1916 to 3 June 1917, then Kptlt. Peter Hermann on 4–26 June 1917, Kptlt. Karl Scherb until 30 October and Kptlt. Gustav Amberger until 17 November 1917, performing 8 patrols, sinking 20 or 21 merchant ships (30,588/30,900 GRT) and a auxiliary warship the 318t HMT Bega. Her largest kill was the freighter Ramillies on 21 July 1917, at 2,935t. She operated in the North Sea and the eastern North Atlantic. She notably sank numerous Scandinavian sailing ships. The second-largest vessel bagged was the British tanker Bullmouth on 28 April 1917 while en route from Glasgow to Hampton Roads, about 125 miles northwest of Tory Island in Ireland. The whole crew survived.

She met her fate southwest of Milford Haven, at the entrance to the Bristol Channel, when her periscope was spotted by the US destroyer USS Fanning. While submerged, she was showered with depth charges until her dive plans and depth control were damaged and inoperative. Lieutenant Commander Amberger decided to save his men and surface, with the crew coming onto the deck with their hands raised. Two crew members remained below deck to scuttle U58 by opening the flood valves and went down with her. The remaining 36 were rescued and ended as POWs. The wreck was later located.

U59

U-59 was ordered on 6 October 1914 at AG Weser, Bremen, Yard number 214, laid down on 13 July 1915, launched on 20 June 1916 and commissioned on 7 September 1916. As part of the II Flotilla
from 20 November 1916 to 14 May 1917 under Kptlt. Freiherr Wilhelm von Fircks until 14 May 1917 she performed 4 patrols and sank 14(13 German sources) merchant ships (28,050 GRT) and damaged one for 6,526 GRT in the North Sea and the eastern North Atlantic. The largest ship bagged was the British passenger ship Canadian (9,309 GRT) on 5 April 1917 while en route from Boston to Liverpool, 47 miles northwest of Fastnet in Ireland. Just one sailor diede, close to the torpedo hit. U-59 was escorted into the North Sea by three barrage breakers on the evening of 14 May 1917, but stormy weather saw her drifting further north, into a freshly laid German minefield, west of Horn Rev. One detonated and flooding started, but contained in one compartment, so it seemed most of her crew could escape, but the escort ships also entered the minefield in the darkness so only four men survived. The wreck was discovered by a Danish diving expedition in 2002 under 33 meters, broken into two but the 10.5 cm deck gun was salvaged now at the Strandingmuseum St. George in Thorsminde.

U60

U-60 was ordered on 6 October 1914 from AG Weser, Bremen, Yard number 215, laid down on 22 June 1915, launched on 5 July 1916, and lead boat of her improved subclass. She was commissioned on 1 November 1916. She differed notably by her more powerful diesel engines, to achieve a higher surface speed. Furthermore, she was active with the II Flotilla from 13 January 1917 to V-Day (11 November 1918) under Kptlt. Karl-Georg Schuster from 1st November 1916 to 31 October 1917, then Kptlt. Karl (i.V.) Jasper on 1–20 November and Kptlt. Franz Grünert until she was surrendered. She made 10 patrols in which she bagged 52 merchant ships (107,940 GRT) and damaged three (7,447 GRT) mostly in the eastern North Atlantic.
The largest ship sunk by her was the British cargo ship Armadale, carrying troops and equipment (6,153 GRT on June 27, 1917, 160 miles northwest of Tory Island between Manchester and Thessaloniki. 3 died as a result, but she floated long enough for the crew and soldiers to escape.
Surrendered in November 1918 she was attributed to the United Kingdom on November 21, but during transfer to the scrapyard in 1921, she ran aground off the east coast and was abandoned as a total constructive loss. She was scrapped or rusted away in the long run.

U61

U-61 was ordered on 6 October 1914 from AG Weser, Yard number 216, laid down on 22 June 1915, launched on 22 July 1916 and commissioned on 2 December 1916. Active with the II Flotilla
in the North Sea and Bay of Biscay, as well as in the adjacent eastern North Atlantic from 15 February 1917 to 26 March 1918 she was commanded by Kptlt. Victor Dieckmann from 2 December 1916 to 26 March 1918, under which she performed 9 patrols, sinking 32 merchant ships (83,291 GRT)*, one auxiliary warship (1,273 GRT), damaged 6 merchant ships (21,054 GRT) and one 1,020 tons warship damaged plus two auxiliary warships (3,424 GRT). *Or 34 ships, 84,861 GRT.

On October 15, 1917, she was spotted by the Cassin class destroyer USS Cassin off the south coast of Ireland. But lieutenant Commander Dieckmann manage to send a torpedo on target, which hit and shattered her stern. However, Cassin, dropped depth charges which damaged U-61’s conning tower and forced her to submerge deeper. Cassin survived and returned to base to be repaired. This was a rare draw. The largest ship sunk by U-61 was the 6,515 GRT British passenger steamer Etonian on March 23, 1918, 34 miles southeast of Kinsale, Ireland, underway from Liverpool to Boston. 7 men went down with her.
Three days after the sinking of the Etonian, by March 26, 1918 in the evening, U-61 surfaced, and was caught through the St. George Channel into the Irish Sea by the British patrol boat PC 51 just 300 meters away. She attempted a ramming attack, but her rudder jammed so U-61 started diving. PC-51 arrived on dropped three depth charges as U-62 was diving, seeing a visible explosion and later floated wreckage and body parts confirming the kill. U61 sank with all 36 crew members.

U62

U-62 was ordered on 6 October 1914 as Yard number 217. She was laid down on 22 June 1915, launched on 2 August 1916 and commissioned on 30 December 1916. She entered service with the II Flotilla from 15 February 1917 to the last day of the war, under Kptlt. Ernst Hashagen from 30 December 1916 (training) and until February to 24 December 1917 in operational service. Next this was under Kptlt. Otto Wiebalck until 9 March 1918 and Kptlt. Ernst Hashagen until 11 November. In all she performed nine patrols claiming 45 merchant ships sunk (109,117 GRT) and two warships notably the 9,517t armoured cruiser Dupetit-Thouars plus the 12,927 GRT auxiliary merchant cruiser HMS Orama and damaged 5 merchant ships (16,483 GRT).

On April 30, 1917, she sank the British sloop and Q-ship HMS Tulip (1,250 GRT) southwest of Ireland, bringing down 102 sailors. Her commander was among the survivors; Norman McCrea Lewis. He was captured and after the war in 1929 gave lectures about their war experience together with the then commander of U-62, Ernst Hashagen. The largest ship sunk by U-62 was the AMC Orama off the coast of Ireland on October 19, 1917, she sank slowly enough that 5 went down. On the same day she shelled the express steamer J. L. Luckenbach 160 miles west of Ouessant, Bay of Biscay. Bu she could not finish her off as USS Nicholson rushed on the scene and forced down U-62 away, later assisting the steamer, saving her to make it in Le Havre on 21 October 1917 with 9 wounded but no fatalities. On 7 August 1918 U62 sank the French armoured cruiser Dupetit-Thouars 400 miles west of Brest and all but 13 were rescued by US destroyers. U62 was surrendered to the allies and likely scrapped between 1919 and 1920.

U99

U99 was ordered on 15 September 1915 as Yard number 250, laid down on 30 November 1915, launched on 27 January 1917 and commissioned on 28 March 1917. She was in the II Flotilla from 7 June to 7 July 1917, making a single patrol under Kptlt. Max Eltester from 28 March to 7 July 1917 between Heligoland and Wilhelmshaven. She went missing at that date, never returned. It is now thought she was sunk by British submarine HMS J2, but the attack was conducted at extreme range and is unlikely to have accounted for U-99.

Her wreck position is unknown, and her fate as well. She disappeared with all hands. During her single patrol in the northern North Sea she probably sank the destroyer HMS Itchen (541 tons) on July 6 between Norway and the Shetland Islands, approximately 70 nautical miles from Pentland Firth. There are conflicting sources between Britain and Germany about her fate, and the British account states U-99 was spotted by J2 on the morning of July 7, at a distance of three to four kilometers, fired four torpedoes with at least one hitting U-99, sinking in a few minutes.

U100

U100 was ordered on 15 Sep 1915, laid down on 30 Nov 1915 and launched on 25 Feb 1917. She was commissioned on 16 April 1917 and entered the II flotilla from May 1917 until the end of the war. From 31 May 1917 to 30 September 1918 she was under Kptlt. Freiherr Degenhart von Loë and for the remaining October-November under Kptlt. Friedrich Götting. Her eight patrols were mostly performed by Degenhart von Loë, sinking 10 ships for 34,505 tons and two damaged (5,272 tons). Her biggest kill was the 9288 GRT Passenger steamer Lake Michigan, all around the British Isles.
She was surrendered in 1918 and was attributed to UK postwar, BU in 1920.

U101

U101 was ordered on 15 September 1915, laid down on 30 November and launched on 1 April 1917; commissioned on 15 May. She was in the II Flotilla, at first under command from 15 May 1917 to 19 Dec 1917 of Kptlt. Karl Koopmann then until 17 June 1918 under Kptlt. Carl-Siegfried Ritter von Georg (awarded the Pour le Mérite) and until 11 Nov 1918 by Kptlt. Friedrich Ulrich for eight patrols and 23 ships sunk (26,253 tons) and three damaged (11,217 tons). Her biggest kills was the 5000t steamer Mexico City. She also badly damaged the 7000t tanker Crenella.
She was surrendered on 21 Nov. 1918 attributed to UK and BU at Morecambre by June 1920.

U102

U102 was ordered on 15 September 1915, laid down on 12 August 1916, launched on 12 May 1917 and commissioned on 18 June 1917 with the II Flotilla. First commander was Kptlt. Ernst Killmann
from 5 August 1917 to 25 November 1917 and Kptlt. Curt Beitzen from 26 Nov 1917 to 27 Sep 1918 for seven patrols between them and only 5 ships sunk (9,340 tons) but the AMC HMS Virginian damaged (10,757 tons) but a torpedo. She survived the hit. Long overdue, she was reported missing. Postwar it was established she sank on 30 September 1918 after striking a mine in the Northern Barrage, east of the Orkney Islands, while homebound and with all hands lost.

U103

U103 was ordered on 15 September 1915, laid down on 8 August 1916, launched on 9 June 1917 and commissioned on 15 July 1917. She joined the II. Flotilla under her loss.
Commander from 26 Aug 1917 to 12 May 1918 was Kptlt. Claus Rücker, performing 5 patrols and sinking 8 ships for 15,467 tons and one damaged, the steamer Grainton (6,042 tons). Her largest kills were the French steamer Depute Pierre Goujon (4,121t) and the British 3000t Glenfruin and Kassanga. On 12 May 1918 she attempted to torpedo RMS Olympic but the latter spotted her, rushed forward and rammed her as she was trying to submerge, but not fast enough. She sank with 10 dead and 35 survivors.

In detail: In the early hours of 12 May 1918, while underway for France in the Channel, jam-packed with U.S. troops under Captain Hayes, RMS Olympic spotted a surfaced U-boat 500 m (1,600 ft) ahead, her gunners opened fire, and she manoeuvred to ram the U-Boat which immediately crash dived to 30 m (98 ft), turning to a parallel course. However as she manoeuvred, Olympic’s bow struck aft of her conning tower, with her port propeller slicing through her pressure hull. The crew blew the ballast tanks, broached the surfaced, and scrambled to evacuate. Some men remained on board to scuttle her. Olympic did not stop, but proceeded to Cherbourg. However, USS Davis sighted a distress flare, picked up 31 survivors. For this only “kill” by a transatlantic liner in WWI, Olympic needed to be drydocked at Southampton two rectify two hull plates dented and some twist. It was discovered that U-103 had been preparing to torpedo Olympic, but the crew never had the chance to flood the two stern torpedo tubes. Captain Hayes was awarded the DSO and grateful US soldiers on board paid for a plaque to be placed in one of Olympic’s lounges to commemorate it.

U104

U104 was ordered on 15 September 1915, laid down on 4 August 1916 and launched on 3 July 1917, commissioned on 12 August 1917. From 1 October 1917 to 25 April 1918 she was under command by Kptlt. Kurt Bernis, performing 4 patrols, until 25 April 1918 when she was lost. She sank 9 ships (14,721 tons, biggest kill).
She had left her base around 10 April for a circle around the British Isles. On 23 April she was detected, and damaged by depth charges from USS Cushing but managed to escape. As the crew attempted to repair damage to the pressure hull, they were caught by the British sloop Jessamine, on the night of 25 April 1918. Jessamine at first attempted to ram her but Bernis ordered to submerge, but was forced to the surface after precise depth charges. No longer buoyant, she could not surrender as she started to sink, with crew members attempted to leave her through the bow hatch. However, only engineer’s mate Karl Eschenberg made it and was rescued alive by the sloop.