June 30, 1934, saw the launch of the third and final pocket battleship of the Deutschland class, the "Admiral Graf Spee," at Wilhelmshaven. Benefiting from the experiences gained from its predecessors, the "Deutschland" and the "Admiral Scheer," rapid progress was made in outfitting the vessel. By November of that year, both the deck construction and the main and secondary armaments were installed. In January of the following year, it successfully completed sea trials and weapon testing and, upon commissioning, replaced the "Deutschland" as the flagship of the German fleet.
Compared to its predecessors, the "Admiral Graf Spee" boasted enhanced armor defense and anti-aircraft firepower, resulting in a displacement increase of nearly 600 tons, with an actual displacement of 12,300 tons instead of the officially announced 10,000 tons. However, with the rise of the Nazis, Germany's military, under government direction, accelerated its expansion, rendering this small "discrepancy" inconsequential. In March 1935, Hitler made a conspicuously conciliatory gesture toward Britain by proposing a unilateral agreement stipulating that the future tonnage of the German navy would not exceed 35% of Britain's.
For the German navy, which lagged far behind the Royal Navy in actual tonnage, this seemingly "self-sacrificing" agreement held no drawbacks. At the time, Britain boasted 150 destroyers compared to Germany's 12, 54 cruisers compared to Germany's 8, 8 aircraft carriers to Germany's none, and 12 battleships and 3 battlecruisers compared to Germany's paltry 3 pocket battleships.
Meanwhile, another former Allied power, Japan, had blatantly disregarded the Washington Naval Treaty, significantly expanding its naval capabilities and becoming a significant threat to British interests in Asia. Britain was deeply concerned that if Germany followed Japan's example, it could further constrain British naval power. Thus, both sides saw mutual benefit. In June 1935, the Anglo-German Naval Agreement was signed.
Admiral Sir Ernle Chatfield, representing the British Royal Navy, expressed in the House of Lords: "I wish to offer heartfelt thanks to the German people for extending a friendly hand to us and voluntarily proposing a tonnage ratio of 35:100 for the German and British navies. If they had proposed another agreement, we could not have prevented it. This agreement enables us to avoid engaging in a military competition with one of the countries in the world, for which we are very grateful!"
German representative Admiral Raeder welcomed the signing of the agreement and reiterated that the German navy would systematically increase its strength and would never be hostile to the navy with the strongest naval power. Regarding the Anglo-German Naval Agreement, Raeder wrote in his diary: "Looking back now, that was the peak of our military expansion and my personal ambition. I believe I have ample reasons to proceed resolutely."
Undoubtedly, the signing of the Anglo-German Naval Agreement provided the German navy with a legitimate reason to break free from the constraints of the Treaty of Versailles, an assessment confirmed by history. For Zhang Hainuo, this agreement held another significance: from then on, Germany could openly rebuild its submarine and naval aviation units. While his overseas project department still needed to continue testing classified technologies and equipment for the German navy, at least there was no longer a need to clandestinely operate submarine units.
In July, the second month after the signing of the Anglo-German Naval Agreement, the German Navy Submarine Command was officially established. Externally, it was just a newly established department, but internally, it already had over 90 experienced officers and more than 700 qualified crew members. Initially, the command included three submarine flotillas. The first flotilla was composed of UB-901 to UB-906, built by Schneider Shipyard, and these six submarines were given historically significant numbers in the German Navy: U-1 to U-6. The second flotilla consisted of four ocean-going submarines, U-911 to U-914, also built by the same shipyard, which were renumbered as U-7 to U-10 upon formal inclusion in the German Navy. The third flotilla initially only had two special submarines, UC-201 and UC-202, for mine-laying and transport tasks, known as U-11 and U-12.
With the legalization of submarine construction in Germany, old shipyards like Kiel, Hamburg, and Bremen-Weser resumed submarine construction work according to the navy's requirements. As the largest submarine supplier to the German Navy, the Brazilian Schneider Shipyard also established its own branch in Germany — Lüngen Shipyard. Upon production, it was expected to build 18 medium-range and 12 ocean-going submarines in the first three years, with production doubling by 1938.
Regarding the selection of the commander for the submarine command, Raeder hoped that Zhang Hainuo or Hessen could take up the position. Although Hessen himself leaned towards accepting Raeder's appointment, Zhang Hainuo impartially recommended the person who history had proven most suitable for the position — Karl Dönitz. Although this submarine tactics expert did not accept Zhang Hainuo's invitation during the secret submarine unit period, his talent in organizing and commanding submarine units was unmatched by Zhang Hainuo or Hessen.
Faced with this divergence, Raeder ultimately took a compromise approach: Hessen and Dönitz were appointed as the commander and deputy commander of the submarine command respectively. Hessen was in charge of submarine production and intelligence affairs, while Dönitz was mainly responsible for crew training and tactical exercises. Both sides were pleased with this arrangement.
Meanwhile, Zhang Hainuo also recommended Helms Heyer to replace him as the head of the overseas project department. In fact, Raeder had long admired and trusted this talented staff officer (during World War II, Helms Heyer was his chief of staff), and his strategic views were also in line with the development of the overseas project department. Thus, Raeder accepted the suggestion. Consequently, Zhang Hainuo was able to extricate himself from the complex affairs of the staff department. He volunteered to serve on one of the three Deutschland-class armored cruisers, as the staff officer, because the staff officer of the "Deutschland" was transferred to the newly commissioned "Admiral Graf Spee," and he soon received the appointment that corresponded to his rank. Additionally, at his urging, the naval technical department decided to test the improved F-type shipborne radar on the three Deutschland-class ships. Colonel Kask, head of the technical department, was the overall person in charge of this test project, and Zhang Hainuo was responsible for the radar testing work on the "Deutschland."
Since its commissioning in April 1933, the "Deutschland" had operated as a sophisticated maritime weapon for 28 months. As Zhang Hainuo stood on the dock observing this warship from a distance, he still marveled at its sleek lines and contours, but behind its aesthetic appeal, Zhang Hainuo saw its weakness in firepower — six 280mm SK C/28 main guns distributed between the front and rear turrets. Despite their advantages in high rate of fire, precision, and long range due to the combined effect of high-precision optical aiming instruments, advanced command systems, and high-quality officer and crew teams, they could not compensate for the inherent deficiency in firepower density. As for secondary and anti-aircraft firepower, eight low-angle single 150mm guns were used to enhance the medium-range firepower of this class of warship, while three 88mm high-caliber guns (initial equipment of the Deutschland) and several 37mm and 20mm dual-mount machine guns were used to deal with enemy aircraft. This design was evidently based on the model of World War I and could no longer meet the requirements for anti-aircraft firepower in the next war.
Zhang Hainuo diligently recorded all of these observations in his navigational records, intending to compile and submit them as a written report to Raeder after the practical radar testing was completed — with several years still to go before the outbreak of war, there was ample time to acknowledge these shortcomings and make improvements.
At this time, the "Deutschland" still maintained its original gray-and-white camouflage, elegant and tasteful, like a graceful gentleman. However, when it came to carrying out combat missions, the crew would apply appropriate camouflage according to the conditions of the destination area: dark concealment colors, gray-and-white wave camouflage, or other camouflage colors suitable for Atlantic voyages.
When Zhang Hainuo assumed the position of staff officer on this pocket battleship, it happened to coincide with the installation of a seaplane catapult on the "Deutschland" in Kiel harbor: a seaplane catapult was installed between the forward bridge and the funnel (its two sister ships had their catapults installed between the funnel and the aft bridge). The shipborne seaplane was usually fixed on this catapult, while the lifeboats and traffic boats were slightly moved to both sides. Additionally, large bi-directional davits were installed on both sides of the funnel on the original davits for launching lifeboats, used for recovering seaplanes.
For a large warship, such a retrofit project was just a minor surgical operation. Zhang Hainuo wasn't sure if the designers of this warship had considered installing a seaplane catapult when they initially designed it, but the clean and concise deck structure of the Deutschland-class armored cruisers left ample space for such modifications. A few days later, the "Deutschland" conducted its first seaplane catapult launch and recovery drill outside Kiel Harbor, and the results were as expected. However, the seaplanes currently used by the German Navy were the twin-seat Heinkel He60 models, with a maximum speed of only 240 kilometers per hour and a cruising speed of 214 kilometers per hour, with a maximum range of 900 kilometers at cruise speed. They were equipped with only one 7.92mm machine gun, making their performance quite limited.
Since joining the ship, Zhang Hainuo hadn't faced the cold treatment typical of new recruits. Lorenz Christoph, who oversaw all the affairs of this warship, was the second captain of the "Deutschland" since its commissioning. He had served in the German Navy for over 30 years, affectionately called the "old sailor" by his subordinates. Lorenz was serious and dedicated to his work, almost fanatical at times, which could make him seem unapproachable and somewhat eccentric, but his wealth of experience and decisive problem-solving earned him the trust of everyone on board, including Zhang Hainuo, who soon joined their ranks.
The executive officer, Luke Kalleg, was a gentlemanly middle-aged officer with melancholic blue eyes. He had participated in the Battle of Jutland and surface actions against Russia in 1918, with a mediocre military record. He was very polite and avoided getting involved in any form of argument. He always executed Captain Lorenz's orders meticulously, making him the type of officer who might not leave a lasting impression but was very reliable.
What particularly pleased Zhang Hainuo was that his friend from the naval training course, Raymond von Schubert, was currently serving as the navigation officer on this warship. It seemed that his experience in the airship fleet was helpful for this position. Leopold Stohn, who graduated in the same class and sailed on the training ship "Graf Zeppelin," also secured a position as the gunnery rangefinder officer on this modern warship.
As the staff officer of the "Deutschland," Zhang Hainuo's authority on board was second only to Captain Lorenz and Executive Officer Luke. With Luke, a hardworking officer who never knew how to slack off, his daily tasks were relatively light: he alternated with Luke to inspect the work of each department, although Captain Lorenz sometimes joined in personally. He also assisted Lorenz in implementing directives from the High Command and Fleet Command, summarizing and archiving this information, and serving as an intermediary in the chain of command.
Before the installation of the improved radar, Zhang Hainuo spent most of his time on board familiarizing himself with the ship and the officers and sailors of each department. Under Lorenz's leadership, the ship's affairs were well-organized, the morale of the sailors was high, and their mindset was optimistic, with all equipment operating smoothly.
After the completion of the seaplane catapult modification, Zhang Hainuo accompanied the ship on two routine patrols at sea, one in the Baltic Sea near its territorial waters, where the sea conditions were relatively calm. In standard conditions, the "Deutschland" could even reach a speed of 26.3 knots—Lorenz told him that during light trials, this armored cruiser had reached a top speed of 28 knots!
During another routine patrol, the "Deutschland" passed through the Kiel Canal into the North Sea region. The Kiel Canal, expanded in the mid-1920s, not only widened the waterway but also reorganized the buildings on both banks, giving it a clean and orderly appearance. Similarly, the "Deutschland" now possessed this style: besides its imposing main gun turrets and sturdy bridge, the deck featured spacious areas everywhere. Even the two quadruple torpedo tubes at the stern were housed in streamlined containers, showcasing a forward-thinking design. Standing on the deck of this warship, Zhang Hainuo and the ordinary seamen received cheers from the coastal residents. Watching the men waving their hats, women tossing flowers, and children running happily alongside the slowly sailing warship, he felt even more convinced that joining the surface fleet was a better fit for him—quite a contrast to his decision in 1916.
"The deck was heavily washed over during sailing against the waves—reason: lack of flare in the forward section of the hull!"
In the rough cabin, Zhang Hainuo wrote down this line in his navigation log with a steel pen. His studies at the Kiel Naval School had provided him with much previously unfamiliar knowledge. In the decade and a half after the Great War, various countries had been experimenting with new ideas in warship design, constantly striving to improve ship performance. As warship speeds increased, so did the requirements for seaworthiness in hull design. The relatively straight bow of the time was no longer suitable for the demands of ocean warfare—except for the unfortunate "Admiral Scheer," the other two pocket battleships had their bows rebuilt in the early 1940s.
Despite the issues with the bow, the Deutschland-class pocket battleships still had their advantages as ocean raiders. During the voyage, Zhang Hainuo focused on understanding its propulsion system. With eight MAN diesel engines and a turbine system, the ship remained stable during sustained voyages. It carried a fuel reserve of 3,500 tons, giving it a range of 10,000 nautical miles at a speed of 15 knots.
After returning from the North Sea patrol, the "Deutschland" entered the dry dock of the Deutsche Werke shipyard in Kiel for a one-month overhaul. Most of the officers and crew went on leave, leaving Zhang Hainuo and Captain Lorenz behind. During this time, the radar system that Zhang Hainuo had been eagerly awaiting was finally scheduled for installation. Due to security concerns, the retrofit was conducted in closed conditions, and everyone, from officers to sailors, who knew about it was required to swear not to disclose the secret to anyone. According to orders from the Naval High Command, the installed radar antenna had to ensure that it couldn't be detected by other ships, meaning it had to be dismantled when entering or leaving port or when other vessels were nearby—a scene reminiscent of history.
Before the installation of the radar equipment, which was cumbersome to dismantle, Zhang Hainuo and the subsequent technical officers who came on board provided valuable data to experts from Gema Company through the actual use of this radar. For example, the theoretical detection range of this improved F-type radar for surface targets reached 15 kilometers, but the actual effective detection range was only 10 kilometers. The theoretical detection range for aerial targets could exceed 80 kilometers, but beyond 50 kilometers, it couldn't distinguish between clouds, large birds, and aircraft.
While presenting further improvement requirements to Rudolf and his team of radio engineers at the Naval Staff, Zhang Hainuo also explained the importance of integrating radar with the gun control system to Admiral Raeder in detailed written reports. To demonstrate the inadequacy of Germany's traditional gunnery techniques against airborne threats, he "borrowed" half a squadron of biplane torpedo bombers from the Naval Air Service—although these were newly produced aircraft from the Dornier company's assembly line, they were not much different in performance from the British obsolete Swordfish torpedo bombers. Their primary purpose was to train a large number of pilots for the Navy. In this small-scale aerial exercise, despite the "Deutschland" maintaining high-speed navigation and employing all anti-aircraft weapons, it only "shot down" three torpedo bombers, while being "hit" by two training torpedoes itself. If live ammunition had been used, the relatively weak armor of the Deutschland-class armored cruisers would have been extremely vulnerable.
However, such results failed to awaken most of the senior naval officers. They adhered to the traditional idea of gun duels and dismissed the results of this exercise, citing laughable reasons such as affecting morale, consuming fuel, and torpedoes, and didn't want the Navy to engage in more practical combat exercises. Fortunately, Rudolf, with his strategic acumen, disregarded the dissent. On one hand, he ordered the technical department to invest manpower specifically into radar fire control research. On the other hand, he requested the engineers to implement corresponding reinforcement designs for the two Scheer-class ships under construction. However, the three Deutschland-class ships had yet to undergo related modifications— their spacious decks provided enough room for improvement. Zhang Hainuo even conducted actual measurements and calculations with the assistance of onboard engineers, annotating the design drawings of the "Deutschland," awaiting orders and resource allocation from the Naval Staff to significantly increase the ship's anti-aircraft firepower density.
"They believe the Polish Air Force lacks the capability for large-scale air raids, and the Fuhrer has assured that Germany will not engage with the British! So, they think it's unnecessary to install anti-aircraft weapons on the Deutschland-class armored cruisers, and it would even affect the aesthetics of these warships!" Raeder replied to Zhang Hainuo's questions with a helpless tone.
Zhang Hainuo couldn't blame Raeder, nor could he. As the German Navy Commander-in-Chief, he was not a dictator within the Navy. There were many senior officers in the Navy, and many matters involving policies and budgets required the establishment of special committees and the consent of the majority of officers. The Ministry of Defense had the power to replace the Naval Commander-in-Chief and appoint new candidates, which was quite different from Hitler's position in Germany—even though Raeder had been supporting Raeder since he took office.
"Well, if they insist on doing so!" Zhang Hainuo said with a rare, malicious tone, "The German Navy cannot be tied down by a bunch of old fossils. Conservatism will ultimately bury the victory at hand!"
"Haeno..." Raeder seemed to understand the meaning behind Zhang Hainuo's words and reassured him proactively, "The generals are also for the good of the Navy. Now is an important period of expansion for the Navy, and every mark should be spent where it matters most!"
Zhang Hainuo responded calmly, "I understand these points, Your Excellency. However, the injustice we encountered during the last war is still fresh in my memory! In my opinion, conservatism is sometimes prudent, but excessive conservatism will hinder historical development!"
Raeder didn't express his approval of Zhang Hainuo's views. Perhaps his current position had made him forget the frustration of more than a decade ago. He said with unusual seriousness, "Haeno, remember, as a German naval officer, you should first understand obedience, then carry a heart of integrity and justice. Finally, I need to reiterate that I don't want to see anyone in the Navy get involved in politics!"
These few words helped Zhang Hainuo regain his balance from his recent slight imbalance. The temptation of power was indeed difficult for people to resist, and whenever there was an opportunity, it would try to influence these ordinary people. Zhang Hainuo was no exception. Just now, he had even felt a fleeting sense of vindictiveness, although it quickly passed. Nevertheless, he had almost succumbed to temptation.
"Your Excellency, as I have repeatedly assured, I personally have no interest in politics, let alone becoming a pawn for others! I just hope that before the next war arrives, the Navy can avoid those unnecessary mistakes! Perhaps, shortly, we will have the opportunity for a real combat test!"