Coeln class cruisers 1916: These were the very last German cruisers of WWI, a gradual improvements of previous light cruiser classes and reaching a new standard in size, speed and armament that was fitting well the needs of the Kaiserliches Marine. Unfortunately the large class of a dozen ships was built in wartime and only SMS Cöeln(ii), Dresden(ii), Wiesbaden(ii), Magdeburg(ii), Leipzig(ii), Rostock(ii), Frauenlob(ii) were actually completed, seeing little action. Not closing the lineage completely they inspired the RMS Emden of the Reichsmarine, first postwar (school) cruiser later of the kriegsmarine. https://bit.ly/3SMYdgb #kaiserlichesmarine #ww1 #cruiser #kreuzer

The last Imperial cruisers

Until that point, Germany had been following a simple and proven path of gradually improving a base model. The lineage of German light cruisers really started all the way back with the Bremen class in 1902, leading to famous series, notably thosed in service in Von Spee's Asian Squadron. But the real start of the linage was traced back to the Magdeburg class in 1911. They really nailed the size, capabilities of new German light cruisers, scouts still capable of engaging their equivalents, the British contemporary Town class, despite having a "weak" armament of only 10.5 cm guns.

The Karlsruhe repeated their "four piper" design, the Graudenz in 1913 showed a new silhouette and radical upsizing, the Wiesbaden of 1915 were the first with 15 cm guns, and the Könisgberg(ii) solidified the design once and for all in 1916. Thus, the Cöln class was just defined as an improvement over the latter, with the same armament but with one extra AA gun, better torpedo tubes, a larger hull but same speed and powerplant, a bit more radius. The large size, 510 feets, enabling better handling in northern rough weather and possible upgrades in the future. What did not change was the armor protection, fairly limited and unchanged since the Magdeburg, albeit applied on large surfaces.

A construction delayed by wartime

However the main incentive for this new class was simpl in 1915 to replace all the cruisers losses since the start of the war, which amounted to thirteen in 1916 and in between, the Kaiserliche Marine ordered ten new cruisers. To gain time, they were ordered as a modified Königsberg(ii) class design and laid down in 1915 (Cöln, Wiesbaden, Leipzig, Rostock, Frauenlob, Esatz Cöln and Emden) and 1916 (Dresden, Magdeburg, Ersatz Karlruhe).

SMS Cöln(ii) became the lead ship, built by Blohm & Voss in Bremen whereas Wiesbaden and Rostock came from AG Vulcan in Stettin, Leipzig and yet unnamed vessels (Ersatz Cöln, Ersatz Emden) from AG Weser dockyard in Bremen. Dresden and Magdeburg in Howaldtswerke Kiel, Frauenlob and "Ersatz Karlsruhe" at the Imperial Dockyard Kiel. Never Germany had ordered so many cruisers of a strictly identical type, at least since 1900.

However, with the war going on, shortage of labour and materials meant delays:
-The first launched was SMS Cöln, by 5 October 1916.
Her sister Wiesbaden on 25 April 1917, and thus could have become the only one with a significant service life.
-However SMS Cöln was completed on 17 January 1918
-Dresden, launched in April 1917, was also completed in march 1918.
-Wiesbaden was canceled however by December 1918, being six months late in completion.
-SMS Magdeburg followed launched on 17 November 1917, nine monthsunder schedule when also canceled.
-Leipzig was launched on 28 January 1918, canceled after seven months of work
-Rostock was launched on 6 April 1918, and also seven months away, same fate.
-SMS Frauenlob, the very last of these cruisers to be launched, on 16 September(October for Conways) 1918 and so too far away from completion.
-The last three "Ersatz", unnamed, despite being laid down in 1915-16, had their construction almost indefinitely suspended. They were never launched and canceled still on the slipway.
Thus, only SMS Cöln and Dresden saw some active service before the end of the war (see later).

Design of the Cöln class

Hull and general design

The ships of the class were 149.80 meters (491 ft 6 in) long at the waterline and 155.50 m (510 ft 2 in) long overall. They had a beam of 14.20 m (46 ft 7 in) and a draft of 6.01 m (19 ft 9 in) forward and 6.43 m (21 ft 1 in) aft. The ships had a designed displacement of 5,620 metric tons (5,530 long tons), and at full load, they displaced 7,486 t (7,368 long tons). Their hulls were built with longitudinal steel frames. The ships had a complement of 17 officers and 542 enlisted men. They carried several smaller vessels, including one picket boat, one barge, one cutter, two yawls, and two dinghies.

Armour protection layout

These cruisers were protected by Krupp cemented steel:
-Armor belt, 60 mm (2.4 in) thick amidships, tapered down to 18 mm (0.71 in) forward.
-Unprotected stern.
-Armored deck 20 mm (0.79 in) thick (stern), 40 mm (1.6 in) amidships, 60 mm forward.
-Armored deck, slopes 40 mm thick linked to the belt armor.
-Conning tower 100 mm (3.9 in) walls, 20 mm thick roof.
-Main battery guns shields 50 mm (2.0 in) thick.
-ASW Protection: Subdivision 24 watertight compartments, double bottom on 45% of the length.

Powerplant

The propulsion systems was repeated of previous designs. Two 3.50 m (11 ft 6 in) diameter bronze propellers, driven by two sets of steam turbines, fed by steam coming from eight coal-fired and six oil-fired Marine-type water-tube boilers. They were all ducted into three funnels, equal size and span amidships but with the forward one was taller. Electrical power came from two Siemens turbo generators and a backup and supply diesel generator, for a total output of 300 kilowatts (rated at the standard European 220 volts). Steering depended on a single large rudder. Performances: The global engine output was were rated as designed for 31,000 shaft horsepower (23,000 kW). Top speed also as designed was estimated 27.5 knots (50.9 km/h; 31.6 mph). However trials, had the lead ship reaching 48,708 shp (36,322 kW) for a top speed of 29.3 kn (54.3 km/h; 33.7 mph) and SMS Dresden did even better at 49,428 shp (36,858 kW) but for only 27.8 knots. They were both regarded as average steamers but good sea boats with gentle motion. This was largely due to the same hull design being repeated and modified on a regular basis since the Wiesbaden. They were highly maneuverable with even a tight turning radius, but of course bleeding speed on hard turns, up to 60% and were noted on trials as "stern-heavy". Radius of Action: Coal storage was "only" 300 t (300 long tons; 330 short tons) as designed. However by filling the many underwater void compartments, up to 1,100 t could be carried onboard. It was mixed, with fuel oil reserved nominally of 200 t but up to 1,050 t, so this made for a 50% supply of both, 2,150 tons in all. Cruising speed was 12 knots (22 km/h; 14 mph) and this enabled as designed 6,000 nautical miles (11,000 km; 6,900 mi). On trials Dresden reached only 5,400 nmi (10,000 km; 6,200 mi) at 12 knots however. At 25 kn (46 km/h; 29 mph) the raduis fell to 1,200 nmi (2,200 km; 1,400 mi) making them still good "interceptors" in the confines of the North Sea.

Armament

The armament was basically a repeat of the Königsberg and Wiesbaden class, all composed of 15 cm guns to face on equal terms the British "Town" class cruisers. The main difference was the addition of a third 8,8 cm AA gun, and new torpedo tubes of the 23.6 in or caliber (Conways). Other sources states incorrectly these were 50 cm (19.7 in) TTs. Their deck was also outfitted to carry on rails up to 200 mines but this capability was never used.

Main: 8x 15cm SK L/45

The ship was armed with eight 15 cm (5.9 in) SK L/45 guns, all in single pedestal mounts:
-Two were side by side forward on the forecastle
-Four amidships on either side
-Two arranged in a super firing pair aft.
Cöln was unique as having their pair amidships guns on the forecastle deck. The rest of the class had them one deck lower.
These guns had for basic caracteristcs:
Shell: 45.3-kilogram (100 lb)
Muzzle velocity: 840 meters per second (2,800 ft/s).
Maximum elevation: 30 degrees
Max range: 17,600 m (57,700 ft).
Ammo supply: 1,040 rounds, 130 shells per gun.

AA guns: Three 8,8 cm SK L/45

The Cöln class were given three 8.8 cm (3.5 in) SK L/45 anti-aircraft guns instead of two on previous classes. Two were mounted on the centerline, astern of the funnels. One was removed in 1918 however as her arc of fire was too limited.
-They fired a 10 kg (22 lb) shell at 750-770 m/s in muzzle velocity (2,500 to 2,500 ft/s).
-Evelation for the MPL C/13 was −10° to +70°
-Rate of fire was 15 RPM
-Maximum range was 10,694 metres/25° and 14,100 metres (15,400 yd) for 43°
-Max ceiling was 9,150 metres (30,020 ft) at 70°

Torpedo Tubes

She was also equipped with four H8 torpedo tubes. These called the final "super torpedo" type were only fitted on wartime ships, the Bayern and the Mackensen classes, SMS Lützow, Hindenburg, and the S 113 class large high seas torpedo boats (destroyers). This new type of torpeod was first designed in 1912 but only entered service in 1915.

The new H8 torpedo measured 315 in (8.000 m), carried a 463 lbs. (210 kg) Hexanite warhead ay 6,550 yards (6,000 m) on 36 knots on the fast setting and 15,310 yards (14,000 m) at 30 knots, double the range. It was powered by a wet heater of the Brotherhood system. Both on the Cöln II were installed on deck, in swivel launchers amidships, abreast the funnels.

⚙ Cöln class specifications
Displacement	5,620 t standard, 7,486 tons fully loaded
Dimensions	155.50 x 14.20 x 6m m (510 x 46 ft 7 in x 20 ft)
Propulsion	2 shafts steam turbines, 14 water-tube boilers 31,000 shp (23,000 kW)
Speed	27.5 knots (50.9 km/h; 31.6 mph)
Range	5,400 nmi (10,000 km; 6,200 mi) at 12 knots (22 km/h; 14 mph)
Armament	8 × 15 cm SK L/45, 3 × 8.8 cm (3.5 in) SK L/45, 4 × 60 cm (23.7 in) TTs
Protection	Belt 60 mm (2.4 in), Deck 20–60 mm (0.79–2.36 in), CT 100 mm (3.9 in), Gun shields: 50 mm (2.0 in)
Crew	17x542

Cölen replaced the cruiser sunk at the Battle of Heligoland Bight on 28 August 1914 and ordered as "Ersatz Ariadne" (she was supposed to replace the old Ariadne). Her keel was laid down at Blohm & Voss, Hamburg, launched on 5 October 1916, fitted-out and commissioned on 17 January 1918. First captain was fregattenkapitän Erich Raeder (yes, the one), training on her way to the High Seas Fleet.

Her initial crew was in part from the survivors of the light cruiser Hamburg and newbies. She started her sea trials by early February, until late March. No particularly grave fixes were made afterwards, but she had a new anti-mine device fitted. On 13 May 1918 she jined II Scouting Group with her unique sister ship Dresden plus the older Königsberg, Pillau, Graudenz, Nürnberg, and Karlsruhe.

Thus potent force was to be thrown into dangerous operations, notablt tasked to protect minelayers creating the mine barrages protecting entrances to various naval bases in the North Sea. This area was known by the Admiralty which sent destroyers and submarines. On 19 June in one of these missions, the squadron was reassigned to try to intercept the HMS Furious just after the Tondern raid. By late August SMS Cöln was detached to lay a minefield off Texel, apparently carrying mines for the first and last time.

Having screws issues which needed repairs in September in dry-docked she was unavilable from 19 September to 11 October. However that late into the war, Erich Raeder was transferred to the Armistice Commission working from Spa in Belgium on armistice negotiations completed on 11 November 1918. Fregattankaptain Kaulhausen took command of the cruiser in replacement.

By October 1918, the II Scouting Group was mobilized for the last, all out attack on the British navy hoped to bring extra bargaining chips to the Negociation table. Hipper and Scheer dreamed of a repeat of Jutland but with less caution, hoping better results. Cöln, Dresden, Pillau, and Königsberg in this large operations were to provoke a British sortie by preying on merchant shipping in the Thames estuary. The others were to bombard Flanders. It was hoped all this would draw the British Grand Fleet.

Scheer however underestimated the loyalty of his crews after almost two years of near-inaction. On the morning of 29 October 1918 this reality surfaced suddenly. When order was given to assemble in Wilhelmshaven the night saw mass desertions and mutinies especially on battleships. Cruisers, having smaller and perhaps more solidary cruisers and lower rank officers were genrally more loyal. In any case, without its precious capital ships, Hipper and Scheer could do little. They cancelled the operation, making the Kaiser say afterwards "I no longer have a navy."

On 9 November 1918, just two days before the armistice went into effect, a reported British presence had Cöln, Graudenz, and torpedo boats scrambled in interception, for nothing. 12 November came and SMS Cöln sailed to Wilhelmshaven under the Imperial War Flag. She was prepared to sail and be interned in Scapa Flow. Captain Kaulhausen was replaced by then by Kapitänleutnant Heinemann which was tasked to watch about the crew and ship during the internment.

Under Rear Admiral Ludwig von Reuter, the German fleet departed for Scapa Flow but when steaming into the Firth of Forth, on the final leg opf the voyage, Heinemann radioed the commander that one of his steam turbines had a leaking condenser, and she was to be assisted to be towed in case by another light cruiser. She took three days eventually but arrived in port on 22 November and was assigned her anchoring position. Captivity drew unrest agains, and von Reuter decided to cut his crews down to limited personal, sending notably troublesome individuals and groups "contaminated" with active Bolshevism.

While negotiations went on, Von Reuter believed the expiration was on 21 June 1919 and did not wanted his ships to be just shared between allies, and on the morning as the British fleet left Scapa Flow for drills, ordered at 11:20 all ships to scuttle as per the preparations made before. SMS Cöln sank at 13:50. It was deep enough for her to stay there, never never raised for scrapping. In 2017, the Orkney Research Center for Archaeology explored her wreck and stuidied the way she was deteriorating under 36 m (118 ft). Still there, she made the day of many scuba divers.
SMS Dresden was ordered as "Ersatz Dresden", laid down at Blohm & Voss in Hamburg in 1916, launched on 25 April 1917 and with a fitting-out work lasting for a full year, commissioned on 28 March 1918. She joined the reconnaissance screen of the Hochseeflotte, last light cruiser in service with the Kaiserliche Marine. She was in II Scouting Group with her sister and the older Königsberg, Pillau, Graudenz, Nürnberg, and Karlsruhe.

Their first operation was a sortie to Norway in 23–24 April 1918 with I Scouting Group, and escorted by the Second Torpedo-Boat Flotilla. Their objective was to attack a heavily guarded British convoy to Norway. Of course the High Seas Fleet sortied in support. But this was a failured as the convoy already had been at sea a day prior. This was a successful British deception. Admiral Reinhard Scheer broke off after a long cruise, not knowing about the whereabout of the convoy.

In October 1918, SMS Dresden was scheduled to lead the grand "final attack" as seen above for Cöln. She was with her sister, Pillau and Königsberg assigned to raid the Thames estuary, others rampaging the Flanders, in the hope to draw out the British Grand Fleet and having Scheer's Hochseeflotte waiting behind. A repeat of the losses at Jutland was hoped to bring a better bargaining position for Germany in the negociations. Sailors however, after many months of inaction, were not of the same mood and widespread mutinies in the night of 29 October had Hipper and Scheer cancelling the operation. Dresden however, which crew was loyal, was ordered to Eckernförde, relaying Kiel as Communications had completely broken there.

SMS Markgraf however arrived in her path, and her unruly crew refused to move out hers way, even aiming her forward main gun turrets at Dresden. Ultimately they backed down and Dresden could leave the port, sailing to Swinemünde. There, the crew partially scuttled her based on reports of mutinied ships en route to attack the cruisers here, which proved false. Dresden was re-floated (cocks had been opened, so air was just pumped back in), and returned to seaworthiness, but after removing the ammunition to pump her dry.

By November 1918, Cöln joined the fleet Rear Admiral Ludwig von Reuter, to internment in Scapa Flow. But due to her poor condition she was not able to join the fleet but only mich later on 6 December, and still leaking badly. On the morning of 21 June, 11:20, Dresden was ordered scuttled herself -again- and started to sink at 13:50. The wreck lays now at the south east of the island of Cava under 25 to 45 m (82 to 148 ft), on her flank and gutted. She was examined in 2017 by marine archaeologists from the Orkney Research Center, making a survey of Dresden, mapped and studying her deterioration. This another spot for scuba diving.

Failed civilian conversion attempts

The eight uncompleted cruisers of the Cöln class in November 1918 were formally stricken on 17 November 1919. The navy considered selling them for civilian conversion and some consideration was left to Ersatz Karlsruhe in particular, just started: She would have receive new diesel engines from unfinished U-boats and a full completion with large holds, central islands, single funnels and service masts. But by 1920, the Deutsches Petroleumgesellschaft acquired rights to the ships. They were to be converted instead all as oil tankers, approved by the Naval Inter-Allied Commission of Control. Military features such as side and deck armor, torpedo bulkheads were to be removed under controled by 31 July 1921. In the end, Wiesbaden and Rostock were towed to Lübeck for conversio, their old machinery removed by November 1920, military features cut away in time. Magdeburg was also demilitarized at Howaldtswerke.

However this whole prospect fell apart: By lack of funds and unrealistic convesion costs, time tables, the company eventually back down and had them scrapped instead: Magdeburg was sold on 28 October 1921 BU in Kiel-Nordmole. Leipzig and Rostock were sold the same year and scrapped in Hamburg. Frauenlob was towed to Deutsche Werke shipyard in 1921 also for demolition. Ersatz Karlsruhe however never left her sliplway and was BU on situ in 1920 already. Ersatz Cöln and Ersatz Emden were sold on 21 and 25 June 1921, launched to clear the slipway towed to Bremen and Hamburg to be demolished.

Read More

Books

Campbell, N. J. M. & Sieche, Erwin (1986). "Germany". Conway's All the World's Fighting Ships, 1906–1921.
Dodson, Aidan (2017). "After the Kaiser: The Imperial German Navy's Light Cruisers after 1918". Warship 2017.
Gröner, Erich (1990). German Warships: 1815–1945. Vol. I: Major Surface Vessels. NIP
Halpern, Paul G. (1995). A Naval History of World War I. NIP
Herwig, Holger (1980). "Luxury" Fleet: The Imperial German Navy 1888–1918. Humanity Books
Tarrant, V. E. (1995). Jutland: The German Perspective. Cassell Military Paperbacks
Wille, Peter (2005). Sound Images of the Ocean: In Research and Monitoring. Springer.
Woodward, David (1973). The Collapse of Power: Mutiny in the High Seas Fleet. Arthur Barker Ltd.
Dodson, Aidan; Cant, Serena (2020). Spoils of War: The Fate of Enemy Fleets after the Two World Wars. Barnsley: Seaforth Publishing. ISBN 978-1-5267-4198-1.
Dodson, Aidan; Nottelmann, Dirk (2021). The Kaiser's Cruisers 1871–1918. Annapolis: Naval Institute Press. ISBN 978-1-68247-745-8.
Koop, Gerhard & Schmolke, Klaus-Peter (2004). Kleine Kreuzer 1903–1918: Bremen bis Cöln-Klasse [Small Cruisers 1903–1918: The Bremen Through Cöln Classes] (in German). München: Bernard & Graefe Verlag. ISBN 3-7637-6252-3.

Links

On wikipedia.org EN
On dreadnoughtproject.org/
On historyofwar.org
On wrecksite.eu