U-66 (UD) Class U-Boote (1915)

Germany: SM U66 to U-70 1915-21.

The U66 class U-Boats were originally ordered in 1913 by the Austro-Hungarian Navy, to Germaniawerft shipyards. Their initial numbers were U-7 to U-11 (U7 class). Internally they were called the UD type, and if delivered, would have been by far the best Austro-Hungarian subs. However, the German government purchased these submarines on 28 November 1914 and rebuilt them to German standards, which took time to complete them in 1915. Then they earned numbers in the U-66 to 70 range after commission, changing assignations and being relatively successful. Collectively they sank 125 ships, and three were sunk in action. #kaiserlichesmarine #ww1 #u66 #u64 #u65 #germaniawerft #uboat #uboote. Note: In cannot find a single photo of any boat in class.

Design of the U7 class:

Development of this class, also called the UD class, is linked to late 1912 requirement by the Kaiserliche und Königliche Kriegsmarine, that at the time just started to acquire or locally build U-Boote for the Adriatic. The KuK K. submarine fleet would remain quite modest during the war, both is scale and individual size, and one of its best was in fact a 1915 captured French sub. In 1912 so, the Government requested from Kiel’s Germaniawerft plans for a new long range, large U-Boat capable of submerging to 50 meters in a minute and 40 seconds, well-armed and with a range of at least 6,500 nautical miles or 12,000 km, to venture out of the Adriatic and roam Mediterranean waters east or west, attacking enemy trade.

It was a radical change of doctrine as until then, like Torpedo Boats, the Austro-Hungarian approach for submarines was for defence only, in home waters and to hurt local trade and shadow fleet moves. Italy was still close to other central powers at the time, and more likely in case of war to enter on the side of Germany. Seeing what direction designs took in Germany and elsewhere for subs, it was clear these new generation boats of large size could be used as commerce raiding assets in a proactive stance in case of war against France or Britain.

The UD class submarines were originally built for Austria-Hungary. After the outbreak of World War I, they were taken over by the Imperial German Navy. The UD class should not be confused with the turbine-powered submarine cruiser UD 1, which was commissioned by the Imperial German Navy in 1918. As early as 1913, Austria-Hungary had ordered five submarines from the Germania shipyard. After the outbreak of World War I in July 1914, the boats were taken over and completed by the German Navy following negotiations with Austria. They were commissioned between July and September 1915 as U 66 to U 70. Indeed, the Austrians themselves became convinced that it would be impossible to take delivery of the boats, towed into the Mediterranean past Gibraltar, held by the British. They would have very likely be captured and interned until the end of the war. As a result, the U-9 class was sold to the Imperial German Navy after negociations on 28 November 1914.

Germaniawerft design was chosen based on their proposal of a derivative of their U23 type in the work at that time in 1912. The latter was however massively up-scaled from 650 to 790 tonnes. It was even very, very large for german standards by 1913 (in fact they were the largest subs planned in Germany), and the U31 and UD types were built in parallel on similar scales but many differences between them. Albeit large, the UD type was a much earlier design and went through a long development. They would have been anyway quite formidable for the Austro-Hungarians, the issue however was that war broke out when they were under construction since 1913. Their tonnage prior to tha standardization and reconstruction was lower, at 695 tonnes surfaced, a 96 tonnes/94 short tons difference. Submerged the difference was 48 tonnes to 885 tonnes. They carried the five torpedo tubes from the start, but the Germans raised the internal space to go from 9 to 12 torpedoes. The original deck gun was the standard Austrian 6.6 cm (2.6 in), replaced by a 8.8 cm (3.5 in) SK L/30.

U-66 was indeed the first ordered on Ordered on 2 February 1913. Construction, like her four sisters, was suspended. Time for the German Government to evaluate how to do with them, until purchased on 28 November 1914. Then Germaniawerft, that stopped all work, while starting alternative plans for completion to German standards. U-66 when renamed, first in class, would be launched much later on 1st November 1915. Little info is available but the amount of work to port them to german standards was considerable apart the points seen above. So, despite being laid down in 1913, they were completed in mid-1915. Oddly enough, their numeration placed in an off-beat timeframe compared to the previous U-57 and 63 classes completed much later. On average from launch to completion it took on average four months, but it took 10 months from laying down the keel as Werk 203-207 at Germaniawerft up to the war and then seven months on average to figure what to do with them and complete them as German U-Boats.

Hull and general design

Plans of the U-66 class (reconstruction)

The U66 class displaced 791 t (779 long tons) surfaced and 933 t (918 long tons) submerged, and a grand total al counted of 1150 tonnes. She certainly was the largest class of submarines ever planned in 1913, with an overall lenght of 69.50 m (228 ft) overall and a pressure hull inside that was 54.66 m (179 ft 4 in) long. In beam she was in the norm however of U-67 and U-63 with 6.30 m (20 ft 8 in) overall in which was a pressure hull 4.15 m (13 ft 7 in) wide. Her total height above the waterline to the top of her periscopes was 7.95 m (26 ft 1 in) for a draft down to the keel of 3.79 m (12 ft 5 in).

Her overall design showed a straight prow like 1914 boats instead of the later rounded one discovered in pool tests with models. Sghe also had the typical narrow chin, straight section at the waterline and a slightly raised deck forward above the torpedo tubes (this feature was increase on 1916 designs). Her hull ratio was of 11. The outer hull was flattened on top, meeting flat sides with gentle slopes and cutouts water scoops running all the way to the tail. Wikipedia is dead wrong in statng she had only one shaft. It was unheard of for a submarine that large and certainly a bad idea for manoeuvering. Her conning tower was the 1914 style with a low deck section and hatch built in, taller section with a small post for the helmsman and the main kiosk structure wrapped around the central persicope conning tower going all the way down to the pressure hull. A second protected hatch was behind, where the officers stand and watch the horizon. As usual, the deck had a sponson-like enlargment for the forward main gun, and barriers. The two telescopic wireless radio masts were anchored on the flattened starboard bulge deck close to the hull, either side of the CT. They supported navigation lights and were folded and stored down in recesses. Her crew was comparable to other boats, with 4 officers and 32 enlisted men.

The pressure hull was composed of 7 separate compartments, with ballast tanks fore and aft and on the sides bulges, as well as regular tanks and oil tanks. The pressure hull was not a straight tube, it was narrowing forward where the four 45 cm caliber torpedo tubes were located (the usual norm was two 50 cm tubes instead) and aft as well with a single 45 cm tube. The two main sections were separated by a concave and convexe bulkheads just below the CT well. They could have 1.3-1.4t torpedo compensating tanks as well fore and aft a 2t+ trimming tank, c1.3t drinking water tank under deck and forward dive planes were leaf-shape, their axis directly below the forward tubes. There was a droppable extra lead false keel with a few bolts in emergency as well. There was a small boat encased under deck.

Forward were located the commander’s cabin and officer’s, warrant officers mess, sanitaries, galley and distilled water tank, the control room behind the concave bulkhead, for the two periscopes, an attack, larger and observation one, thinner. The former was in front of the CT and partly internal, passing though the conning towing bell into the pressure hull. The convex bulkhead separated the Control Room from the larger engine room. In there were two diesels side by side, close to oil fuel tanks and distilled water tanks. Below this deck were located the battery. There was thin separation leading aft to the electric engines and motor room. The last flat bulkhead separated it from the aft torpedo room with two torpedoes in reserve, narrowed up. Shafts were supported by small struts and the rudder was a classic “L” with a middle hinge. It’s lower part matched a short spine running under the aft keel section for better protection when at 0°. There was no prow structure but a cable guard however, running from the prow to the stern, anchored above the CT portico.

Power plant of the U66 class

The U66 class had two shafts with classic, standard made three bladed bronze propellers. They were driven by two in-house powerful Germaniawerft diesels, two-stroke 6-cylinder for a total of 2,269 shp (1,692 kW) total (U63 class had two 1150 PS units each, 2,200 PS/1,618 kW/2,170 shp total), the largest mounted yet, for surface running. They were completed by electric engines, which diverged in class. U66 and her sister U67 due to shortages had two Siemens-Schuckert or SSW electric motors rated for 620 PS each, 1,223 shp (912 kW) total. U68, 69 and 70 had instead four Pilcher eletrcif engines for roughly the same nominal global output of 1,240 shp. These SS engines were more powerful than in the U63 class (1,200 PS/883 kW/1,184 shp) for submerged runs. Top speed was not stellar but average at 16.8 knots in service, even 17 knots (31 km/h; 20 mph) surfaced on trials, but top speed underwater of 11 knots (20 km/h; 13 mph) submerged also on trials, 10.3 knots in service. To compare, the U63 class had a top speed of 16.5 knots (30.6 km/h; 19.0 mph) surfaced and 9 knots (17 km/h; 10 mph) underwater.

Range started with a modest oil fuel bunkerage of 87 tonnes (src navypedia) or 89 tonnes (conways) versus 115-118t on contemporaries. Whatever is true, this made for a range of 1,200 nautical miles (2,200 km; 1,400 mi) at 12 knots (22 km/h; 14 mph) and 100 nmi (190 km; 120 mi) at 4 knots (7.4 km/h; 4.6 mph) underwater. To compare the U63 and U51 class did better, the former reaching 9,170 nmi (16,980 km; 10,550 mi) at 8 knots (15 km/h; 9.2 mph) surfaced and 60 nmi (110 km; 69 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged. Howeber the U66 had the same diving operating depth as the others, but could be from fully surfaced to fully underwater in a minute and 40 seconds with some help from the crew doing their “prow run”, helping tipping the balance down faster. So overall good speed, especially underwater, the best so far of any German submarines.

Armament

Unusually, give, their design started in 1913, the U66 class was not fitted with the usual four 5cm (19.7 inches) tubes, two forward and two aft. Instead they were planned with the older 45 cm (17.7 in) torpedo tubes, with enough space to cram four in the bow and a single one in the stern. Given their size and the space on, board they could carry a total of 12 of them, including five pre-loaded in tubes, leaving seven torpedoes to store in both forward and aft compartments, likely one spare aft and six forward. This was completed by the usual 8.8 cm (3.5 in) SK L/30 deck gun, coming with 253 rounds ion storage. It was later replaced during the war by the more potent 10.5 cm (4.1 in) SK L/45 deck gun. U66 and sisters used it to sink sailing vessels or small coasters wherever possible.

Torpedo Tubes

U66 and sisters were armed with the now surplus 45cm (17.7 in) C/06 or C/06 D tubes designed for U-Boats and present from U3 onwards until the introduction of the 50 cm tube from U-19 onwards back in 1912. Thus, this made sense for the Austro-Hungarians back then. Decision to convert the tubes was not taken due to emergency, but in 1915, U-boats carrying such tubes were now rare. The 45 cm torpedo
could be either the 45 cm (17.7″) C/06 of 1907 (1,704 lbs./773 kg, 222 inches (5.650 m) long, 270 lbs/122.6 kg TNT warhead) capable of reaching 1,640 yards (1,500 m) at 34.5 knots or 3,380 yards (3,000 m)at 26 knots thanks to a Brotherhood system, used in practice and training by 1915 (or even the 1903 C/03 or 03D). Indeed in service they were given the more recent C/06 D. Itwas heavier at 1,786 lbs. (810 kg) and used instead a wet heater for better performances, notably 1,640 yards (1,500 m) at 34.5 knots and 5,470 yards (5,000 m) at 27 knots. They were also outfitted with gyro angle setters of +/-90°.

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.

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°

Note: In 1916 for some and 1917 for the remainder, the 8,8 cm/27 TK L/30 C/08 was relocated aft. In its place was fitted a 105/43 TK L/45 C/16 forward. Thus all boats had now two deck guns for surface kills, which was much more efficient and quicker. From early 1918 it seems (for the survivors) the aft 8,8 cm/27 gun was removed to improve stability.

Author’s rendition of the U66 class (in preparation)

⚙ U66 specifications
Displacement	791 t (779 long tons) surfaced, 933 t (918 long tons) submerged
Dimensions	69.50 x 6.30 x 3.79 m (228 ft x 20 ft 8 in x 12 ft 5 in)
Propulsion	1 shaft, 2× Germania 6-cyl. 4-stroke diesels 2,269 shp, 2× SSW EM 1,223 shp
Speed	16.8 kts surfaced, 10.3 kts submerged
Range	7,370 nmi/8 knots surfaced, 115 nmi/4 knots submerged
Armament	5× 45 cm TTs (4 bow, 1 stern, 12 torpedoes), 1× 8.8 cm SK L/30, see notes
Max depth	50 m (160 ft)
Crew	4 officers, 32 enlisted men

Career of the U66 class

U66 (1916)

U-66 was laid down on 1st November 1913, launched on 22 April 1915 and commissioned on 23 July of that year as werk 203. In her career she sank 25 ships (total 73,847 tons) and damaged two for a total of 6,714 tons, took one as prize for a total of 1,005 tons and damaged one of 5,250 tons. Once commissioned into the Imperial German Navy under command of Kapitänleutnant Thorwald von Bothmer (Related to the Royal House Order of Hohenzollern). The 31-year-old was already a 13-year veteran of the Imperial German Navy and considered an elite commander. His boat was assigned to the V. Baltic Flotilla (U-boote der Ostseestreitkräfte V. Unterseeboots-Halbflottille) on 17 October. By late September, the British submarines started to slip through the Skagerrak (not a small feat in itself !) and arrive into the Baltic for an offensive against German shipping there. The goal was in general to deny free passage of German cargo, but especially iron ore from neutral Sweden, vital to the war industry. This was such a strategically important mission and according to Paul G. Halpern in his book part of the German response was U-66. She was towed behind an “innocent-looking vessel”, connected by a telephone line attached to towline and able to cast it off as soon as an enemy submarine would be detected. No chance encounters however ever happened. By 15 January 1916, she was transferred to the frontline IV Flotilla with sisters U-67 and U-68 for the second German U-Boat offensive.

The German command decided to send U-boats independently around Scotland and the Irish Sea where they were rarely present until then and seldom expected so defences were lax. The goal was to block the the western entrance to the English Channel. U-66 sank a first ship on 5 April 1916 under Bothmer, off Fastnet Rock. He came upon the 3,890-ton British refrigerated cargo ship Zent from Garston to Santa Marta, 28 nautical miles from Fastnet. All 49 crewmen went down with her but a master and nine sailors, landed at Queenstown. 2 days later, U-66 sent to the bottom French sailing vessels, the 151-ton Binicaise and 397-ton fishing smack Sainte Marie. It was west of Scilly Isles. On 8 April this was the Spanish Santanderino, 18 nautical miles from Ushant (3,346-ton, 1890) from Liverpool to Havana. However she surfaced and gave her 15 minutes notice for passengers and crew to abandon ship. There were 36 survivors later rescued by a Danish steamer. On 9 April she sank the same day the steamers “Eastern City” (4,341-ton, shelled and sunk 18 nautical miles from Ushant), “Glenalmond” (2,888-ton with iron ore, 2 torpedoes north of Ushant), and Norwegian “Sjolyst” (20-yr-old from Nantes to Manchester). In all three cases the crews survived. A day later she sank the British steamer Margam Abbey (4,471 tons) southwest of Lizard Cape and later the Italian freighter Unione (2,367t), making for a total of nine ships, 22,848 tonnes in six-days, breaking records. However by April 1916, like her sisters and others of the IV. Flotille she was recalled by Admiral Reinhard Scheer, the new Hochseeflotte CiC to port. She received maintenance and her crew a well deserved rest.

By mid-May 1916, Scheer wanted her and others to take part in an ambushg to destroyer a part of the British Grand Fleet, drawn at sea. The bait was the raid on Sunderland. He called the ambush party “nests” of U-Boates and minefields. U-66 was part of nine boat sent on position on 17 May in the central North Sea. At first she scouted for the British fleet over 5 days and then took her intended position along with U-63, U-51, U-32, U-70, U-24, and U-52 off the Firth of Forth, on 23 May. U-43 and U-44 were sent off Pentland Firth in front of Scapa Flow with orderes to remain until 1 June, awaiting a coded message reporting when the British fleet would sail out, but unbeknown to them, room 40 deciphered the departure order of the submarines already. The delayed departure of the Hochseeflotte redirected to the Skagerrak and failure to receive the coded message had the ambush qualified later of “complete and disappointing failure”. U-66 did actually saw parts of the British fleet but did nothing due to their speed, screening vessels, and having no orders. At 09:00 on 31 May she still reported by wireless seeing eight battleships, light cruisers and destroyers 60 nautical miles east of Kinnaird Head. The ambush failing had an impact on the Battle of Jutland as the Hochseeflotte was forced to engage a much larger enemy.

Next patrol by U-66 was in August 1916. On the 11th she sank east of Aberdeen the 600t 3-masted Norwegian bark Inverdruie from Sandefjord to Hartlepool. On 19 August she however had her best kill of her career, off Flamborough Head. She torpedoed the cruiser Falmouth (Town class) while crossing Standlinie II around noon under tow, already crippled. Indeed, by the end of the month she was ordered to take part in another ambush for the postponed raid on Sunderland. U-66 was one of 24 U-boats plced in a five “Standlinie” in the way of the Grand Fleet, specifically in Standlinie II with U-63, U-49, U-45, and U-64 over 35 nautical mile off Flamborough Head, in place by 19 August. But room 40 foiuld that plan and the Grand Fleet sortied already on 18 August. Falmouth was hit by two torpedoes at 1,000 yards (910 m) on her starboard, flooding her forward and aft. Yest she was steered to the Humber with three destroyers and an armed trawler. U-66 fired again but narrowly missed in two more attempts over 2 hours before breaking the pursuit, notably due to a depth charge attack that causes some damage. Falmouth limped at 2 knots across Standlinie II only to be snk by U-63 the next day.

By late 1916 she escorted out at sea the German merchant raider Wolf (Karl August Nerger) for a 15-month raiding campaign to the Atlantic, Indian and Pacific anc back home. U-66 on 11 December sank the 1090t Norwegian steamer Bjor off Ryvingen and Swedish 311-ton sailing ship alander off Oxö, Tornio. When unrestricted submarine warfare was decided by Kaiser Wilhelm II after the “turnip winter” of 1916–17 due to the British blockade, operations resumed from 1 February 1917 in a “fire first, ask questions later” mood. Rules of engagement went out of the window and on 1 March 1917 she sank the 1,733 tons Norwegian steamer Gurre from Narvik and Fredrikshald and Hull with iron ore. Next she bagged the 1,005-ton Livingstone off Charente (with ammonium nitrate used for shells). She seized her as a prize east of Shetland. By late March, she sank the 3,597-ton cargo Stuart Prince underway to Alexandria, 85 nautical miles off Broad Haven and 5 days later, the 5-masted bark Neath, 28 nautical miles south-east of Fastnet Rock (former captured German bark R. C. Rickmers in Cardiff) loaded with sugar. Bloody April represented 860,334 tons of Allied and neutral shipping sunk, never surpassed in history. U66 also bagged the 6,117-ton tanker Powhatan 25 nautical miles from North Rona, Outer Hebrides from Texas to Kirkwall. On 5 June she bagged the 3,472-ton Italian steamer Amor from Galveston, 200 nautical miles from Fastnet Rock and the same day the 4,234-ton steamer Manchester Miller with cotton, 10 nautical miles off Amor, with a crew including three Americans. Two days later she attacked the 4,329-ton Ikalis from New York 170 nautical miles from Fastnet ans the 3,157 tons Cranmore from Baltimore 150 nm northwest of Fastnet, damaged, and beached, surviving the war.

U-66 biggest kill in her career was the 6,583-ton British steamer Bay State, on 10 June. Working for the Warren Line she was from Boston with a $2,000,000 war cargo for Liverpool. This happened 250 nautical miles (460 km; 290 mi) northwest of Fastnet (no casualties) and 4 days later, she bagged the 1877 Norwegian grain bark Perfect from Bahía Blanca, bound for Copenhagen by gunfire east of Shetland. On 17 June, Kptlt. Gerhard Muhle took command. The 31-year-old was a classmate of von Bothmer and joined also the Kaiserliche Marine in April 1902. On 9 July she sank the 1,161-ton Spanish steamer Iparraguirre from Santander to Bergen with pitwood off the Orkney Islands. Next was the British steamer African Prince on 21 July, 60 nm NN of Tory Island and the 1,322-ton British sailing ship Harold close to her. These were her last victims in six patrols. On 2 September she departed Emden for the North Channel and a day later she reported a position in the North Sea close to known British minefields, her last. She was never heard of again. A postwar German study suggested she struck a mine in the Dogger Bank or was sunk by destroyers, submarines, and net tenders between the 1 to 11 October although this is discounted by Author Dwight Messimer.

U67 (1916)

U-67 was Ordered on 2 Feb 1913 (werk 204), Laid down on 1 Nov 1913 and launched on 15 May 1915. On 4 August she started trials after her commission, under Imperial German Navy Kapitänleutnant Erich von Rosenberg-Grusczyski. On 28 October 1915, U-67 she was considered ready and assigned to the IV. U-Halbflotille until the end of the war. However she had no kill before early 1916, and from March she was under command Kapitänleutnant Hans Nieland. On 16 April, she sank the 2,169t Cardonia. On the 20th the 4,397t Whitgift and on the 22th the French 2,423t Chanaral. Then on 8 December she damaged the British APC HMS Intaba (4,282t). On 28 January 1917 she sank the Danish 1,227t Daisy and on the 29th the Spanish Punta Teno (1,042t).

On 1st February she sank the 2,434t Spanish Butron and a day latere the Greek 1,166t Elikon. 4 days later she sank the Peruvian 1,419t Lorton. On the 19th she sank the 4,953t Headley. On 17 April this was the british 4,928t Kish and a day later the 4,799t Rhydwen and on the 20th the 3,187t Portloe. On 28 April she sank the 2,309t Port Jackson. April 1917 was her best months, four ships for 15,223 GRT in twelve days. Next patrol on 19 July she sank the Danish Harrildsborg (1,547t), on the 24th. she sank the the Swedish Viking and four days later the Danish Rigmor. On 15 September she damaged the British 6,692t Idomeneus. On 21 November the 4,240t Breynton and a day later the 3,834t. On the 27th that was the british trawler Premier. The numerous damaged ship was due to their smaller 45 cm torpedoes.

In December, Oberleutnant zur See Helmuth von Rabenau took command of U-67 but for these last eleven months she sank no more ships. In all, U-67 completed thirteen war patrols and she eventually surrendered to the British on 20 November 1918, a few days after the Armistice. She was BU at Fareham in 1921. In all she sank 17 ships for a total of 39,720 tons, damaged four for 19,048 tons total.

U68 (1916)

U68 was ordered at Germaniawerft, Kiel, Werk 205 on 2 Feb 1913. She was laid down on 31 December 1913 and launched on 1 June 1915, then commissioned on 17 August 1915. Her first and last commander was Kptlt. Ludwig Güntzel. She only performed a single patrol and from 28 November 1915 to 22 Mar 1916 assigned to the IV Flotilla (U-Halbflotilla). She departed the Ems on 16 March 1916 for her first war patrol with an operating area off Britain’s west coast. Güntzel when she spotted a British cargo (under the command of Gordon Campbell), the Farnborough while off SW Ireland. At 07:00, she fired a torpedo at Farnborough, narrowly missed her bow. Farnborough (in reality a Q-ship) continued her same speed and course and 20 minutes later U-68 surfaced at 1,000 yards (910 m) astern and moved to her port quarter to fired a shot across her bow and stopped her.

She dutifully did so, the captain ordering to blew off steam and launching a boat to simulate a surrender. U-68 closed to 800 yards (730 m). At this precise moment, while battle stations had been ordered a while ago, she suddenly raised the White Ensign and the panels covring her guns suddenly fell, reavinbg her battery of 3-in (76 mm) guns. The broadside three of her five rapid fire 12-pounder started to score many hits in succession, firing 21 HE rounds on her deck, CT and hull. U-68 had her outer hull crippled, flooded and started to sink. Farnborough then moved to the spot sje just sank and for good measure dropped a single depth charge right on target. It severed her bow out of the water and her back likely broke. She then started to go down by the stern, while the gunners scored five more hits on her resurfacing conning tower. She sank with all hands off Dingle. A post-war German study blamed Kptlt. Güntzel to have brushed aside procedures when encountering neutral-flagged vessels as Q-ships were already known. Hos flotilla senior, Kommodore Hermann Bauer, recalleed in his post-war memoirs Güntzel as being an inexperienced captain dropped in her his unit without the time to properly train.

U69 (1916)

U69 was ordered at Germaniawerft, Kiel as Werk 206, on 2 February 1913, laid down on 7 February 1914 and launched on 24 June 1915, commissioned on 4 September, under Kptlt. Ernst Wilhelms (related to the Royal House Order of Hohenzollern) until 23 July 1917 (her loss). In all she performed 6 patrols, the first on 4 March 1916 in the IV. Flotilla, sinking 31 ships (total 102,875 tons), damaged one.
Her most successful month was by April 1916 (a year exaclty before most of her sister’s own best month). She sank eight ships for 21,051 GRT in six days. As for her highest tonnage sunk, it was in June 1917 with five ships for 29,808 GRT in nine-days. Half of that accounted for the 13,441 GRT British armed merchant cruiser (AMC) HMS Avenger on 14 June. Avenger patrolled off the Shetland Islands underway back to Scapa Flow, when hit by a single torpedo, port side. These civilian conversions were not design to take a torpedo impact, having large holds instead of heavily compartimented military hulls. Despite her double bottom, she started listing heavily. Only a skeleton crew remained until destroyers arrived, took her under tow, but she continued to flood and foundered ten hours after as her internal bulkheads collapsed unde rpresure. One man was killed, present where the torpedo hit.

U-69 final patrol started on 9 July from Emden, bound for the coast of Ireland. Her last position reported at 02:30 on 11 July was 35 nautical miles (65 km; 40 mi) south of Lindesnes in Norway, underway to Ireland. Author Dwight Messimer took two British sources and believed HMS Patriot sank U-69 on 12 July, confirmed by an observer in a kite balloon deployed by Patriot, that spotted her at 07:00, showing one of the first example of ship-born ASW observation. U-69 submerged but Patriot hunted her down until noon, and two depth charges surfaced a thick brown oil slick that seemed to confirm her claim. A German postwar study doubted Patriot victory and so far, her wreck was never rediscovered, so the book’s page is not closed (neither the family research for all 38 crew on “eternal patrol”).

U70 (1916)

The last boat in class was also ordered from germaniawerft on 2 Fezbruary 1913, laid down on 11 February 1914, Launched on 20 July 1915 and commissioned on 22 September. Her first commander until 15 September 1918 was Kptlt. Otto Wünsche awarded Pour le Mérite, making all her kills and 12 patrols with IV. Flotilla like her sisters, operating notably from Emden. Then as the end of the war was close, she was commanded until 11 November 1918 and her surrender to the allies, by Kptlt. Joachim Born. She was the most successful U-Boat in class, bagging a grand total of 52 ships for 135,288 tons.
She also damaged 5 ships for 24,971 tons and sank the 1,290 tons ASW sloop HMS Rhododendron of the flower class. More detailed records in a future update. She survived the war, was surrendered to Britain on 20 November and was Broken up at Bo’ness in 1919-22.