Where the German K-class Light Cruisers structurally weak?

[Felix C]

I recall reading one of the class suffered considerable structural damage when posted to Spain during the Non-Intervention patrols. Damage due to Atlantic storms. Is this one of the reasons they tended to be used mostly in the Baltic after 1940?

Did the initial torpedoing of different types by British submarines and the quick sinking of the Königsberg by FAA also provide data they were weak?

[RandJS]

Felix,

Yes, they were structurally weak. Triple turrets on lightly constructed hulls. Cracks were found in upper deck and longitudinal girders on Leipzig following a storm in March 1937. Weight of extra topside equipment added to problems. Fuel had to be taken from end bunkers, then mid ship bunkers to prevent "bending". Several other issues effected the situation: light armor, mixed fuel requirements also prevented them from effectively operating with their "big" sisters. I'm sure early losses also contributed to their lack of usage.

German Cruisers of World War Two, M.J. Whitley ISBN 0853687463 provides good information regarding all the types.

Hope this helps.
Rand

[Paul Lakowski]

Groner reports the ships were "very crank" which means the suffered from twisting under stress, but most lighter German warships had this problem and we don't have any info on how allied warships respond. Kreuzer "Karlsruhe" suffered major cracking in a pacific Typhoon in 1936 and had to effect emergency repairs in San Diego before limping home. This resulted in a major rebuild of the midsection of this warships 1938-1939 costing 5.7 million RM.

That rebuild involved adding new outer hull plates over 55% of the ships hull length that added another 10-14mm armor. Likewise 16mm additional armor was plated over the weather deck to improve the longitudinal strength of the warship and deck protection. In addition both diesels were removed along with their fuel bunkers [200t] and the ship was limited to 30knots . In total these modifications to the ships increased displacement to ~8350 tons and the beam also increased to 16.8m.

http://navypedia.org/ships/germany/ger_ ... gsberg.htm

Without these modifications the other warships were limited to using 680 tons fuel oil which cut endurance to about 2000nm @ 18knots. At least with the rebuild , the Karlsruhe was able to bunker ~1450 tons of oil and manage 3340 nm @ 18 knots, which made it the best of the K/L class cruisers.

[thaddeus_c]

was the terrible roll in even (relatively) calm seas solved by the overhaul and was it ever contemplated for the others?

a (possibly) stupid question, conversion to coal?

imagine something akin to M-class but much larger, used as minelayer with the capacity of the proposed Minenleger Projekt http://german-navy.de/kriegsmarine/ship ... index.html

[Felix C]

I recall that famous photo of Leipzig nearly cut in half by Prinz Eugen. The former was changing powerplants at the time.

[Edward L. Hsiao]

Gentlemen,

During the invasion of Norway,the German light cruiser Karlsruhe was fired upon by Norwegian shore batteries which must have made near misses and damaged her hull. Then later on,Karlsruhe was torpedoed by the British sub Traut. The captain of the cruiser had no chose but to abandon ship. She was later finished off by one of her escort ships. Talk about stucturally weak during combat. Karlsruhe was not a strong ship at all.

Sincerely,

Edward L. Hsiao

[Paul Lakowski]

It might be more to refer to them as top heavy a problem common with many German warships of the time. As I recall Karlsruhe was already heavily damaged in storm which lead to emergency rebuild. Then it is crippled by torpedoes from a British Sub and then finished off with a pair of Torpedoes from a German GTB. That's 4 torpedoes to sink a very light cruiser!!!

Karlsruhe then left Kristiansand with three of the torpedo boats as escorts. The British submarine HMS Truant was positioned outside the fjord, and when her crew spotted the German ships, she fired a spread of torpedoes.[9] Karlsruhe zig-zagged to evade the torpedoes, but two still hit the ship; one struck her bow and the other hit amidships. They blasted large holes in the hull and allowed thousands of tons of water to flood the ship. The flooding disabled her engines and electricity generators, which cut off power to the pumps that were trying to keep pace with the progressively worsening flooding. With the pumps shut off, there was no hope to save Karlsruhe, and so her commander, Friedrich Rieve issued the order to abandon her two hours after the attack. The torpedo boat Greif took off her crew and fired two more torpedoes into the ship to ensure that she sank.[4][10]

Rieve and his executive officer were both severely criticized for failing to take all possible steps to save Karlsruhe in a later investigation into the sinking. The report concluded that since the ship was still afloat after two hours, and two torpedoes were required to sink her, it might have been possible to take her under tow back to Kristiansand or another port. In addition, the forward pumps still had power, and so the flooding could have been slowed enough to permit a return to a safe harbor.[10]

http://en.wikipedia.org/wiki/German_cruiser_Karlsruhe

Perhaps the 8300 ton Karlsruhe was not as bad as many suggest. The 13,000 ton HMS Edinburgh was crippled after two torpedo hits from a Uboat and it took several more Torps from Zerstörers , two days later to sink.

[Polar bear]

The 13,000 ton HMS Edinburgh was crippled after two torpedo hits from a Uboat and it took several more Torps from Zerstörers , two days later to sink.

not several, just two, one from a German (Hermann Schoemann) and one, the coup de grâce, from a Brit (Foresight).

greetings, the pb

[Paul Lakowski]

Not that its important but according to O'Hara it was Z25 that launched the torpedoes that hit Edinburgh.

[JAG13]

It might be more to refer to them as top heavy a problem common with many German warships of the time. As I recall Karlsruhe was already heavily damaged in storm which lead to emergency rebuild. Then it is crippled by torpedoes from a British Sub and then finished off with a pair of Torpedoes from a German GTB. That's 4 torpedoes to sink a very light cruiser!!!

Karlsruhe then left Kristiansand with three of the torpedo boats as escorts. The British submarine HMS Truant was positioned outside the fjord, and when her crew spotted the German ships, she fired a spread of torpedoes.[9] Karlsruhe zig-zagged to evade the torpedoes, but two still hit the ship; one struck her bow and the other hit amidships. They blasted large holes in the hull and allowed thousands of tons of water to flood the ship. The flooding disabled her engines and electricity generators, which cut off power to the pumps that were trying to keep pace with the progressively worsening flooding. With the pumps shut off, there was no hope to save Karlsruhe, and so her commander, Friedrich Rieve issued the order to abandon her two hours after the attack. The torpedo boat Greif took off her crew and fired two more torpedoes into the ship to ensure that she sank.[4][10]

Rieve and his executive officer were both severely criticized for failing to take all possible steps to save Karlsruhe in a later investigation into the sinking. The report concluded that since the ship was still afloat after two hours, and two torpedoes were required to sink her, it might have been possible to take her under tow back to Kristiansand or another port. In addition, the forward pumps still had power, and so the flooding could have been slowed enough to permit a return to a safe harbor.[10]

http://en.wikipedia.org/wiki/German_cruiser_Karlsruhe

Perhaps the 8300 ton Karlsruhe was not as bad as many suggest. The 13,000 ton HMS Edinburgh was crippled after two torpedo hits from a Uboat and it took several more Torps from Zerstörers , two days later to sink.

Wasnt the commander court martialed and convicted for abandoning a ship that was deemed salvageable? He was a few kilometers (20?) from shore as well IIRC.

[JAG13]

Btw, did Leipzig and Nuremberg correct these issues? Stability, range, strength...

BEcause Nuremberg did see service in Norway, but Leipzig was barely repaired after taking a torpedo in 1940 and used just for training.

[Paul Lakowski]

Karlsruhe was stiffer after the rebuild and removal of the roll tanks which were ineffective?

Nuremburg & Leipzig were improvements but both still suffered from twisting that was feared would result in cracks much like the Karlsruhe , so the fuel was limited as precaution however this limitation was reduced to 180 tons less than max fuel suggesting the bigger hulls of these two helped to solve the problems.

Groner does note all these cruisers were quite maneuverable platforms with good sea keeping.

Gerhard Koop book on these light cruisers notes that the official range of the K class was 7300nm @ 17 knots -while the diesels allowed for 8,000nm @ 10 knots . He also notes it took 10-15 minutes to change over from diesel to Turbine [and back again] since only one propulsion system could drive the shafts. The ship also had to be stationary to do this. The L class cruisers had a third center shaft dedicated to the diesel but to run both turbine and diesel shafts required ' double-couple' these drive systems which in turn required the ship to halt for 10 minutes or more. This sounds like an operational decision that would have to be made well ahead of any tactical clash with enemy units making surprise attacks very difficult to handle.

For the L class the endurance figures are given as only 3780 nm @ 15 knots, while Erich Gröner puts the diesel figures at 3900@ 10knots. The L class had more diesel fuel bunkerage than the K class [ 348 tons vs 261 tons ]; so its hard to imagine the K class had twice the endurance on diesel.

[thaddeus_c]

always thought the Leipzig-class had grown so large why was Admiral Hipper-class slotted in above them? why not just build 5 more light cruisers?

[JAG13]

Thx Paul, so they were pretty much COSOD or CODOS, it is still surprising that they got so little range on their 2nd attempt at combined propulsion, it seems the tech wasnt mature enough yet (10 mins stationary at war...) and the hulls were just too small to allow for a relevant fuel quantity that could take advantage of the propulsion design.

always thought the Leipzig-class had grown so large why was Admiral Hipper-class slotted in above them? why not just build 5 more light cruisers?

I think they had already almost filled its AGNA allowance for CLs.

[thaddeus_c]

always thought the Leipzig-class had grown so large why was Admiral Hipper-class slotted in above them? why not just build 5 more light cruisers?

I think they had already almost filled its AGNA allowance for CLs.

wouldn't it be pretty easy to strike a deal with GB to build something BELOW their heavy cruiser allowance?

just re-reading over the information and the Hipper-class seems like oddball, no real place in the fleet. seems like they would have had most of problems worked out to build a series of light cruisers?

or just call them heavy cruisers and install 8" guns? (assume 6 instead of the 8 on larger OTL Hippers?)