Bismarck: Not Ready For Action?

Illustration of battleship Bismarck as she left Norway in May 1941:"Bismarck kept the dark gray colour at the ends of the hull including the white bow water and stern water as indicated on your sketch, leaving Norway May 21...Bismarcks and our black and white stripes ended at the waterline." Paul Schmalenbach, gunnery officer Prinz Eugen from John Asmussen's site: file and website 1)Pre-Rheinübung aerial identification markings. Anynobody

By Timothy P. Mulligan

Naval History, February 2001

When the German battleship Bismarck escaped from a Norwegian fjord in May 1941 and began her epic breakout into the North Atlantic, she was the most feared warship in the world. The Royal Navy hunted her down mercilessly, and her sinking has been lauded ever since as one of the Admiralty's greatest accomplishments. New evidence suggests that the great battleship may not have been ready to go into battle.

Much of the appeal of the saga of the German battleship Bismarck concerns the many variables that ultimately determined her fate. What if fleet commander Admiral Günther Lütjens had topped off her fuel tanks before departing Norwegian waters, or what if he had not transmitted the long signal on 25 May 1941 that allowed the British to gain a fix on the battleship's position? What if the Bismarck had headed back to Norway instead of making for France after sustaining damage in the battle on 24 May with the British battlecruiser Hood and battleship Prince of Wales? Should Lütjens have tried to finish off the wounded Prince of Wales on 24 May instead of pursuing his original mission? Amidst these imponderables one factor appears constant: the presumed power and deadly proficiency of the Bismarck. Yet a review of available evidence casts doubt even on this premise and raises the question of whether the Kriegsmarine committed the Bismarck to action before she was ready.

To her opponents the 50,000-ton warship seemed a monster, possessing limitless capabilities for evil. Winston Churchill in November 1939 considered the Bismarck's entry into the campaign as potentially "disastrous in the highest degree, as it can neither be caught nor killed, and would therefore range freely throughout the oceans, rupturing all communications."¹ President Franklin D. Roosevelt nervously counted the Bismarck's options after she sank the Hood to include a bombardment of Halifax or New York, a voyage around the world to Japan, or the seizure of the key island of Martinique in the Caribbean.² Time has not altered this perception of awesome power, as reflected in the most recent history of the Bismarck operation: "Her crew had been honed to the utmost degree of efficiency and her equipment had been fine-tuned to optimum performance. . . . Bismarck was the ultimate product of German naval technology and recent training had undoubtedly honed her crew up to the razor's edge of perfection."³

The evidence, however, suggests otherwise.
Several material problems became manifest during the Bismarck's brief operation. During the attempted breakout through the Denmark Strait on the evening of 23 May, her rudder jammed to starboard, nearly causing a collision with the cruiser Prinz Eugen. A few hours later the Bismarck's forward radar broke down, caused by the shock of the main battery salvos fired at the shadowing British cruiser Norfolk. The Prinz Eugen's war diary of 24 May noted that "the radar apparatus . . . often went out of order on board Bismarck." Finally, both German warships experienced chronic radio communications problems with the mainland, failing to receive key messages and often unable to transmit important information successfully. The infamous "long signal" sent by Lütjens on 25 May—which allowed the British to fix the Bismarck's position after the Germans had broken contact with their pursuers—actually was a retransmission of four messages the fleet commander had attempted to send the previous night.⁴ Moreover, the fact that the Bismarck did not receive many signals that routinely were picked up by the Prinz Eugen indicates there were less proficient radio personnel on board the battleship than the heavy cruiser, a shortcoming apparently attributable to better communications training standards for personnel who passed through Marinestation der Ostsee (Naval Station Baltic), whence Prinz Eugen drew her crewmen, as opposed to Naval Station North Sea, the regional administrative center for the Bismarck.⁵

Illuminating as these examples might be, they nevertheless represent events that took place after the Bismarck had departed on her mission. Such mechanical or equipment problems might reveal themselves only under operational conditions, or simply confirm the risks faced by every new ship entering combat. But in the case of the Bismarck, additional evidence from earlier in her history suggests more general problems in combat readiness—evidence furnished in the assessments of German naval authorities at the time. 

Timetables and Training

Grand Admiral Erich Raeder, Navy commander-in-chief, belonged to the battleship school that dominated most navies at the beginning of World War II. The conflict came when the Kriegsmarine had just begun a major expansion program and could not match the combined forces of Britain and France, yet the surface navy won an impressive if costly victory in the conquest of Norway in April 1940. One month later, as German forces won a stunning victory in the Low Countries and France, Raeder believed increasingly that his capital ships had to demonstrate their value to guarantee a future for themselves. His directive of 23 May 1940 criticized the cautious orthodoxy he found among his operational commands and urged a "new offensive spirit," particularly in the use of battleships. "I am ultimately convinced," he wrote, "that the loss of one of these [battleships] would little change the situation at sea or the war's final outcome, but through continuous action much can be won. By not using them, or by delaying their use, we not only gain nothing, we lose the future of the Navy as well."⁶ 

Many of the antiaircraft guns on the Bismarck were arranged poorly, such as these guns on the starboard side, forward. In the foreground, under a tarpaulin, is a single-mount 2-cm gun; above and to the left is a twin-mount 3.7-cm gun, whose field of fire is restricted by the bulk of Turret "Bruno" (upper right).




This guideline remained in force as the Bismarck prepared for operations. Impressive as she was, the Bismarck remained a new ship with a new crew about to enter combat for the first time. The commander, Kapitän zur See Ernst Lindemann, together with his first officer, first artillery officer, and engineering officer, all were highly capable and qualified men who had served in instructional schools or in staff positions—but none had seen action since the war began.⁷ As his ship was rushed through final preparations before departing on operations, Lindemann offered a modest yet intriguing assessment of the Bismarck's status in the war diary on 28 April 1941: 

The training level attained compares well with that for a capital ship in the prewar years. If the crew for the most part lacks actual combat experience, I am nevertheless confident that this ship could fulfill any mission demanded of it. This feeling is strengthened by the vessel's material combat quality, which in combination with the attained training level has produced such a level of confidence in everyone that, for the first time in a long while, we feel ourselves at least the equal of any opponent.⁸

Lindemann's caution doubtless reflected a concern over the loss of invaluable training and sea trials time to the severe winter of 1941. After her commissioning on 20 August 1940, the Bismarck accomplished some basic training and tests in the Baltic from September to early December 1940, then returned to her home port of Hamburg. With that harbor and the Kaiser Wilhelm Canal (now the Kiel Canal) iced over throughout the winter, the Bismarck had to postpone the resumption of Baltic training from late January to early March. The severity of the cold, with temperatures falling to -15ûC (about 5ûF), froze up pressure gauges and electrical lines and forced a temporary shutdown of the boiler rooms. By the time the battleship could transfer to the Baltic, five irreplaceable weeks of at-sea training had been lost.⁹

This view of the base of Turret "Dora" (beneath the guns of Turret "Cäsar") shows the 10.5-cm stereoscopic range finder protruding from the back of the turret. Originally built into all the turrets, the range finder on Turret "Anton" had been removed before the Bismarck's final voyage, because it was prone to water damage in rough seas. The local control periscope extending from the center side of the turret also was prone to the same problem.

Perhaps even more important, the intensified training that followed could not build on the experiences gained during the two-month commerce raiding sortie (codenamed Operation Berlin) just completed by the battlecruisers Scharnhorst and Gneisenau. Their experiences during the North Atlantic winter already had led to one modification on board the Bismarck—the removal of the 10.5-cm stereoscopic rangefinder from the forward main battery Turret "Anton," because it was overly prone to water damage from running seas.¹⁰ When the two older vessels, which already had seen extensive action in the North Sea and off Norway, finally put into Brest on 22 March 1941, the Bismarck had commenced her final exercises in the Gulf of Danzig. On board the Scharnhorst and Gneisenau, division officers prepared detailed reports of lessons learned during Operation Berlin in the areas of navigation, communications, ordnance, signaling, and medical considerations, while specialists detailed the performance of radio, radar, and encryption equipment. These reports naturally required study and comment by several staffs before the final recommendations were approved and acted upon, procedures that demanded patience and time.¹¹ The rush to commit the Bismarck to action, however, negated the benefits of this evaluation process. Lindemann was hard pressed to apply only the most practical lessons of the operation, which proved difficult enough—refueling at sea, the launching and recovery of onboard aircraft, gunnery and damage control drills, cooperation with U-boats, and joint movements in formation. 

All but ignored in the rush were the even more critical lessons at the command level. Admiral Lütjens had directed Operation Berlin by a precarious juggling of his own judgment as fleet commander against the instructions of the Seekriegsleitung (Naval War Staff), the operational guidance of Naval Group Commands North and West (depending on the vessels' location), and on occasion the instincts of his battlecruisers' captains. Although the 22 Allied merchant ships sunk or captured marked the operation a success, many differences of opinion had emerged over specific actions taken and prospective opportunities won or lost. Lütjens himself had no time to reflect on these matters, as preparations for the upcoming Rheinübung (Exercise Rhine) kept him shuttling constantly among Brest, Berlin, Paris, Kiel, and SwinemŸnde.¹² These vital command issues remained unexamined and unresolved, and played a significant role in the Bismarck's ill-fated sortie.

Ironically, the question of the Bismarck's readiness for action already had cast a shadow on the history of Operation Berlin. Hardly had the Scharnhorst and Gneisenau broken into the Atlantic when, on 8 February 1941, the Seekriegsleitung directed Group Command North to prepare for joint exercises of the Bismarck and Prinz Eugen.¹³ This first reference to the latter warships acting together obviously anticipated the next stage in surface operations, yet it came at a time when the Bismarck was still frozen in Hamburg harbor. On 12 March—while the Bismarck stood in Kiel harbor, about to begin her final workup exercises—Admiral Lütjens received instructions to curtail Operation Berlin so as to have the Scharnhorst and Gneisenau available to renew operations at the end of April, in combination with the planned breakout of the Bismarck and Prinz Eugen. This effectively ended Berlin, as both of the former ships needed refitting and repairs, and only the Gneisenau possibly could meet an April deadline to renew operations (in the end she too fell out because of damage sustained in air attacks while in Brest).¹⁴ Thus, the most successful fleet commerce raid ended in part to accommodate a fixed timetable of the Bismarck's presumed availability, despite the lengthy delays already imposed on her readiness by severe weather.¹⁵
Lindemann learned only on 19 March that his ship was expected to be ready for operations by the end of April. The Seekriegsleitung's need to maintain secrecy not only kept the battleship's commanding officer in the dark about the planned timetable, but thereby further reduced his training time. To complete preparations and final outfitting for operations, Lindemann had to plan on completing all training and ordnance tests by 2 April, eliminating an additional three to four weeks of exercises from his already foreshortened training program. And even that limited time suffered inroads from the need to address nagging material problems, particularly the operation of the side cranes (described by Lindemann as "extremely delicate and unreliable") and continual replacement of glass panes and slide valves broken or dislodged by practice firings of the main guns.¹⁶

Ultimately, the fixed timetable that had so determined the tempo of events itself fell victim to developments beyond its control. As of 2 April plans still called for the Gneisenau's eventual participation in the operation, but severe damage by British air attacks on 6 and 10 April would immobilize her for at least four months at Brest.¹⁷ Rheinübung remained on schedule to begin on 28 April, but with only five days to go the Prinz Eugen struck a mine outside Kiel. The explosion damaged fuel bunkers, propeller shafts, and a turbo-generator, forcing the cruiser into dry-dock for nine days and finally revising the timetable so rigidly adhered to up to this point. In a meeting with Raeder on 26 April, Lütjens raised the possibility of postponing the operation until the Scharnhorst or even the Tirpitz could participate as well, but the original plan remained in place and they awaited the completion of the Prinz Eugen's repairs. In the end, the cruiser required more work than originally planned, and a recurrence of the Bismarck's chronic problem with the port crane on 14 May imposed a further delay.¹⁸ Rheinübung finally began on 18 May, nearly three weeks behind schedule.
Yet the Bismarck and her crew were unable to use this grace period to full advantage. The official training period had concluded according to the original schedule, and could not be reinstated on an improvised basis. Lindemann conducted additional onboard drills throughout this period, but first priority had to go toward operational preparations. The battleship's state of readiness essentially remained that established during the abbreviated exercises and tests conducted by the Artillerieversuchskommando für Schiffe (the Naval Ordnance Testing Command for Warships, or AVKS) from 19 March to 2 April 1941. 

The Naval Ordnance Tests

The testing results were detailed in a 106-page report submitted by the AVKS on 31 May 1941, four days after the Bismarck had been destroyed. The ordnance experts complained correctly of the time and conditions constraints imposed on them: not all tests could be completed; some of the artillery fire-control and radar equipment was installed too late for testing; and the He 111 aircraft supplied for antiaircraft firings were available for only 90 minutes. The report nevertheless presented 117 observations and recommendations regarding improvements to the battleship's weapon systems. Most of these involved fairly minor alterations and changes, as would be expected with any new vessel, but some revealed potentially serious problems of direct bearing to the Bismarck's combat readiness, shortcomings that may instead provide a postmortem on her destruction.¹⁹

Problems with the main battery turrets commanded immediate attention. Described as "a fault of fundamental significance" by the AVKS, the main ammunition hoists were susceptible to a weight distribution problem that carried brass-cased main charges beyond their proper loading area. One such occurrence in training led to the complete breakdown of a hoist for an extended period. Moreover, the turrets' local control periscopes proved insufficiently watertight, particularly in the forward turrets; in rough seas water penetrated both the turret and the periscope itself, with the risk of serious damage to the latter. It only need be noted that the Bismarck developed a bow list shortly after receiving her first hit from the Prince of Wales' guns during the morning engagement on 24 May, which increased the forward decks' exposure to running seas and the likelihood of additional water damage. The rapid silencing of the Bismarck's forward turrets in the climactic battle of 27 May perhaps reflects these weaknesses as much as the early damage sustained by the main fire-control station.²⁰

Closely related was a general ammunition problem, specifically with insecure armor caps on the heavy and medium artillery shells. German shell designers allowed more cushion space between the explosive filler and the armor cap than did their Allied counterparts, with a consequent weakening of projectile integrity. The AVKS, which apparently recognized this condition only in terms of the relative looseness of the caps evident in loading drills, nevertheless considered "a sweeping improvement" as necessary. During the naval engagement of 24 May, the Prince of Wales was struck by several German shells that did not explode, duds that otherwise might have eliminated the newest British battleship altogether.²¹

The question of onboard antiaircraft artillery, however, represented the greatest area of AVKS interest, amounting to nearly one-third (36 of 117) of the specific recommendations or observations offered. The very first of these criticized the location of the main flak control position in the crowded foretop fire-control station, where up to 25 officers and men jammed in a confined and exposed space attempted to coordinate flak guns on both sides of the ship. AVKS instead proposed a significantly reduced post in the foretop and a "flak operations center" below decks, next to the existing forward antiaircraft plotting room, to provide more efficient, telephone-linked coordination with flak batteries. Improvements also were required for the four flak fire-control platforms (one on either side of the control tower, and two midships aft), which housed the critical range, direction, and height finders for the long-range flak batteries. Problems with internal motors had knocked individual towers out of commission during training, in one case for two full days. The batteries controlled by these towers consisted of sixteen 10.5-cm guns in eight twin-mounted locations, four on either side of the superstructure. The twin mounts, however, represented two different models, the older C31 and the more advanced C37. AVKS "urgently desired" the replacement of the older model with the new, but recommended as well changes in the safety switches and other gunsight electrical components of the C37.

Particularly telling were the ordnance experts' assessments of problems associated with the light flak guns, responsible for defending against close-in attacking aircraft. Not linked to any central fire-control system, the light flak consisted of four battery groupings, one for each of the ship's quarters. Each grouping included two twin-mount 3.7-cm guns; the forward groupings added one quadruple-mount and two single-mount 2-cm guns each, the aft groupings added three single-mount 2-cm guns. AVKS first criticized as "inadequate" the positioning of the 3.7-cm twin mounts in both forward groupings, as their movement and fields of fire were partially restricted by other parts of the superstructure. Second, they recommended the placement of two additional 2-cm quadruple mounts on the forward searchlight platform "to significantly improve an otherwise weak flak protection forward." Even at this relatively early date, AVKS recognized the need for additional light flak, proposing that new battleships accommodate multiple-mount antiaircraft guns atop their main battery turrets. At the same time, the AVKS found the existing means of supplying ammunition to the rapid-firing, quadruple-mount 2-cm guns on board the Bismarck as "completely inadequate," with improvements "urgently needed."

Finally, the AVKS pointed out that, at least during the trials and training period, the battleship never had received an adequate supply of antiaircraft technical manuals and diagrams: "Six months after the ship's commissioning, the needed materials were for the most part still lacking." The Bismarck's flak crews simply had to get by with what they had when departing on a mission from which so much would be demanded of them.²²

Conclusion

The Naval Ordnance Testing Command's recommendations were typed and distributed even as the Bismarck met her destruction with more than 2,200 officers and men. In due course her sister ship Tirpitz absorbed these and other lessons, adding more advanced equipment and many more flak guns, but in the end these improvements did not save her either. Given Allied technological and material superiority—already evident in the Bismarck chase—it ultimately mattered little whether Lütjens and Lindemann had eluded their pursuers in late May to reach temporary safety in Brest. The ultimate fate of the Bismarck was sealed by the stacked naval odds accepted by Nazi Germany in the pursuit of limitless goals with limited means. 

Yet the Kriegsmarine owed its men the best possible chance to fight and survive. Rheinübung in May 1941 involved major yet predictable risks not present in the sortie by the Scharnhorst and Gneisenau during the winter: better weather and longer daylight facilitated Allied aerial efforts; no other major German warships were at sea to divide British forces; and the element of strategic surprise had been lost. To compensate, the Bismarck and her crew deserved every advantage of training, equipment, and weaponry available. Instead, their training and sea trials were cut short because of weather and an inflexible operational timetable, and the ship was committed to action before technical and material shortcomings revealed during routine tests could be put to paper, much less implemented. 

The Royal Navy may have been equally guilty of committing the Prince of Wales to action before she was ready, and nearly paid the same price. But the Admiralty paired its newest battleship with the veteran Hood before sending her in harm's way. Moreover, the Prince of Wales represented one of nine British capital ships on Atlantic station at the start of Operation Rheinübung, five of which participated in the Bismarck hunt. This total excludes Royal Navy aircraft carriers, which played such a decisive role in the operation. The British risk in using the Prince of Wales therefore represented a relatively smaller stake than the German gamble. 

The Bismarck remained a great and powerful ship, manned by fine and courageous men, an image of strength that perhaps blinded German naval leaders as much as it did their opponents. Had Rheinübung been converted into a simple feint into Norwegian waters, it would have bought time to study and incorporate the lessons missed in training, tested British reactions as a basis for future planning, and facilitated the later use of both the Bismarck and Tirpitz, perhaps in combination with the warships in Brest. In the end a perceived need for action triumphed over sagacious planning. To the many variables of the Bismarck's odyssey, future students must address the question: what sense of desperation drove Raeder and the Seekriegsleitung to hurl their newest battleship into action before she was ready?

Dr. Mulligan is an archivist with the National Archives in College Park, Maryland. His publications include Neither Sharks Nor Wolves: The Men of Nazi Germany's U-Boat Arm, 1939-1945 (Annapolis, MD: Naval Institute Press, 1999).

1. Churchill War Cabinet Paper 116, 3 November 1939, quoted in The Churchill War Papers, Volume 1: At the Admiralty, September 1939-May 1940, Martin Gilbert, ed. (New York: W. W. Norton, 1993), p. 328.  
2. Robert E. Sherwood, Roosevelt and Hopkins: An Intimate History (New York: Harper & Brothers, 1948), pp. 294-95.  
3. Robert J. Winklareth, The Bismarck Chase: New Light on a Famous Engagement (Annapolis, MD: Naval Institute Press, 1998), pp. 47, 60-61.  
4. Kriegstagebuch (KTB, war diary) of the Bismarck (reconstructed), 23-25 May 1941, reproduced on National Archives microcopy T1022, Records of the German Navy, 1850-1945, roll 2791, record item PG 47897; KTB Prinz Eugen, 23-25 May 1941, T1022/roll 2815/PG 43849.  
5. See the discussion in the most recent edition of Jochen Brennecke's authoritative Schlachtschiff Bismarck (Hamburg: Koehler, 1997), pp. 233, 587n.  
6. Oberbefehlshaber der Kriegsmarine und Chef der Seekriegsleitung, "Weisung an Gruppenbefehlshaber West, Flottenchef," 23 May 1940, published in Michael Salewski, Die deutsche Seekriegsleitung 1935-1945, 3 vols. (Frankfurt am Main: Bernhard & Graefe, 1970-73), vol. 1, pp. 522-24; Salewski provides an excellent assessment of this directive (pp. 200-202), as does former Admiral Rolf Güth, Erich Raeder und die englische Frage. Betrachtungen zur deutschen Marineführung 1928-1945 (privately published, 1995), pp. 100-103.  
7. Biographical data in Walter Lohmann and Hans H. Hildebrand, Die Deutsche Kriegsmarine, 1939-1945: Gliederung, Einsatz, Stellenbesetzung, 3 vols. (Bad Nauheim: Podzun Verlag, 1956-64), pp. 111, 291-292, 202, 209, 263, 334.  
8. KTB Bismarck, 28 April 1941, T1022/roll 2791/PG 47897.  
9. KTB Bismarck, 28 April 1941, T1022/roll 2791/PG 47897, entries for 24 January-28 February 1941.  
10. Siegfried Breyer and Gerhard Koop, Schlachtschiff Bismarck. Eine Technikgeschichtliche Dokumentation (Augsburg: Bechtermunz Verlag, 1997), p. 55.  
11. The best collection of these evaluation reports are reproduced as appendices to the KTB of the Gneisenau for 15 February-22 March 1941, T1022/roll 2996/PG 47977.  
12. See KTB Flottenchef, 23 March-15 May 1941, T1022/roll 4246/PG 34679.  
13. KTB 1/Seekriegsleitung (1/Skl), 8 February 1941 (S. 97), T1022/roll 1665/PG 32038; Skl an Gruppe Nord, "Gemeinsame Übung ÔBismarck' und ÔPrinz Eugen,'" 8 February 1941, in 1/Skl KTB Teil C, Heft Ilb 1941, "Westraum-Atlantikktiste Flottenoperationen," T1022/roll 1720/PG 32163.  
14. KTB Flottenchef, 12 March 1941, T1022/roll 2323/PG 34678.  
15. Lütjens' marvelously detailed war diary throughout Operation Berlin is reproduced as KTB Flottenchef, 27-31 December 1940, T1022/roll 3961/PG 34676, 1 January-22 March 1941, T1022/roll 2323/PG 346778-678. Except for Gerhard Bidlingmaier's Einsatz der Schweren Kriegsmarineeinheiten im Ozeanischen Zufuhrkrieg (Neckargemund: Scharnhorst Buchkameradenschaft, 1962), and Graham Rhys-Jones's The Loss of the Bismarck: An Avoidable Disaster (Annapolis, MD: 1999), histories of the Bismarck operation overlook the relationship between Operation Berlin and Rheinübung.  
16. KTB Bismarck, 18-31 March 1941.  
17. 1/Skl I op 410/41 Gkdos, "Weisung für weitere Unternehmungen von Überwasserstreitkräften," 2 April 1941, in 1/Skl collection "Bismarck-Operation Rheinübung," Band 1, Heft 1, T1022/roll 1783/PG 32552; KTB Flottenchef, 6-11 April 1941, T1022/roll 4246/PG 34679.  
18. KTB Flottenchef, 15 April-15 May 1941, T1022/roll 4246/PG 34679; the account of Lütjens' meeting with Raeder, "Am Sonnabend 26.4. Vortrag Flottenchef bei Ob.d.M.," appears in the same Skl collection noted above, T1022/roll 1783/PG 32552.  
19. Artillerieversuchskommando für Schiffe, "Schlussbericht: AVKS-Erprobungen auf Schlachtschiff Bismarck," 31 May 1941, copy located as enclosure to Serial 1384, Reports of the Naval Technical Mission to Europe, Office of Naval Intelligence, Records of the Office of the Chief of Naval Operations, Record Group 38, National ArchivesÑCollege Park (hereafter abbreviated "AVKS-Schlussbericht").  
20. "AVKS-Schlussbericht," pp. 19-20, 25.  
21. "AVKS-Schlussbericht," p. 30; on German shells and those that did not explode on board the Prince of Wales, see William H. Garzke and Robert 0. Dulin Jr., Battleships: Axis and Neutral Battleships in World War II (Annapolis: Naval Institute Press, 1985), pp. 299-300, and the same authors' Battleships: Allied Battleships in World War II (Annapolis: Naval Institute Press, 1980), pp. 180-88.  
22. "AVKS-Schlussbericht," pp. 55-89; illustrations of the different types of flak guns can be found in Werner F. G. Stehr and Siegfried Breyer, Leichte und mittlere Artillerie auf deutsche Kriegsschiffen, Sonderheft Bd. 18 in the Marine-Arsenal series (Wolfersheim-Berstadt: Podzun-Pallas, 1999), pp. 3-5, 26-35.