Blue Whale Diving into the Sea, a True Hero—Huang Xuhua, Recipient of the Medal of the Republic and the Second Chief Designer of China's Nuclear Submarine

The era is filled with turbulent waves, yet you buried your head and willingly became a silent pillar; in an era of poverty and blankness, you stood tall and became the nation's greatest wealth. Your life, like a submarine in the deep sea, is silent but possesses infinite power!" Academician Huang Xuhua, although you have left us, your achievements will forever be recorded in history, inspiring us to move forward continuously.

Huang Xuhua, the chief designer of China's first generation of nuclear submarines, worked anonymously and diligently for the national interest. Over the years, he devoted himself to technological breakthroughs, making significant contributions to the development and leapfrog progress of nuclear submarines. In the year he was awarded the honorary title of "Medal of the Republic," Huang Xuhua was years old.

In the year, Huang Xuhua graduated from the Shipbuilding Department of Shanghai Jiao Tong University, filled with patriotic fervor. That same year, he secretly joined the underground organization of the Chinese Communist Party at the university, embarking on a lifelong journey of dedication to the Party's cause. After the founding of the People's Republic of China, he engaged in research and design work for both civilian ships and military vessels. In the year, due to his experience in replicating Soviet-style conventional submarines and his graduation from the Shipbuilding Department of Shanghai Jiao Tong University, he was selected by the Party organization to participate in the development of nuclear submarines.

On the monumental achievement of China's nuclear submarine program, there is a day that should forever be remembered, which is the day of [specific date]. It was on this day that Nie Rongzhen submitted a top-secret report to the Central Committee of the Communist Party of China and Mao Zedong, titled "Report on the Development of Missile Nuclear Submarines." This report, which had been thoroughly researched and argued by Nie, was concise, containing only a few hundred words, yet it addressed the monumental task of "developing missile nuclear submarines." The development of missile nuclear submarines represents a significant strategic and historical milestone in China's independent and self-reliant development of advanced national defense weaponry. On [specific date], this report was finally approved by Mao Zedong with his signature, officially designating it as a "top-secret project" of the Republic. It was also at this time that Huang Xuhua became one of the key members of China's nuclear submarine development team.

Nuclear submarines represent a cutting-edge engineering marvel that combines an underwater nuclear power plant, an underwater missile launch site, and an underwater city. When Huang Xuhua began exploring the hull design for nuclear submarines, the first challenge he encountered was determining the optimal hull shape. Ultimately, Huang Xuhua and his team chose the most advanced, yet also the most difficult, option—the teardrop-shaped hull. Huang Xuhua recalled: "From the perspective of hull design, nuclear submarines simply couldn’t continue using the old hull shapes. Conventional submarines relied on limited-capacity batteries, which prevented them from staying submerged for long periods. Therefore, their hulls had to be designed to facilitate surfacing for recharging under favorable sea conditions. As a result, conventional submarines had to account for a large contact area with the air when surfacing to recharge. Their hull shapes and overall design had to adapt to sea conditions, particularly in scenarios involving waves and rolling motions. Consequently, their hull shapes inevitably resembled those of surface ships. This is why such designs were referred to abroad as 'fleet-type' hulls." "However, with the advent of nuclear submarines, nuclear power eliminated the need to surface for recharging, completely overcoming the vulnerability of conventional submarines being exposed during charging. If we had continued using the hull shapes designed for surface-charging ships and applied them underwater, it would have been highly disadvantageous. At the very least, such designs would have faced significant underwater resistance and poor maneuverability."

Fully recognizing this, Huang Xuhua and You Ziping immediately organized research on the structure of nuclear submarines after the program demonstration. They collaborated extensively with relevant institutes and universities, conducting nearly a dozen specialized studies, including theoretical explorations of short shell plastic stability and new design calculation methods. During this period, they also conducted validation tests on the structural parts of the pressure hull using dozens of scaled models. Before the product structure design, they had already performed simulated strength tests on the pressure structure welding models. These tests showed that their designed pressure hull met the safety requirements for deep diving, and the actual submarine tests also proved that the design and construction of the first nuclear submarine's large-diameter pressure hull were completely successful.

To determine the feasibility of the teardrop-shaped hull design, Huang Xuhua, You Ziping, and their team spent countless sleepless nights in the laboratory. Everything had to start from scratch—there were no test wind tunnels or large-scale water tanks, no thick steel plate processing equipment, and most critically, China had no land-based nuclear power plants at the time. They exhausted all available experimental equipment and facilities from various industries, "borrowing hens to lay eggs," ensuring every design blueprint underwent thorough scientific validation and repeated testing. Huang Xuhua said, "We made do with what we had, starting from the existing test conditions, methods, and equipment. It didn’t matter how rudimentary they were, as long as we could conduct experiments. Of course, some investment was also necessary to create or improve certain conditions to meet the basic testing standards. When the teardrop-shaped hull testing progressed to the physical ship model stage, we encountered significant difficulties. At first, we processed and built a miniature submarine ourselves. As a designer, I had to—and should—participate. Back then, conditions were limited, and the test model ended up being unrealistic during processing because it developed many cavities, rendering the data unusable—it was a failure. Later, Jiangnan Shipyard supported our experiments, and we first built a wooden model there, conducting tests in the water tank to obtain relevant data. However, wood still differed from steel. After that, Jiangnan Shipyard helped us construct a steel miniature submarine for further testing. The results once again confirmed the feasibility of the teardrop-shaped hull design. At the time, we weren’t entirely confident about its maneuverability. We then conducted tests in the wind tunnel at Peking University, but the setup wasn’t perfect. Later, we chose to repeatedly test the design using facilities at the Fifth Academy of Aerospace."

Through extensive pool towing and wind tunnel tests, Huang Xuhua and his team obtained a wealth of experimental data, laying a solid foundation for demonstrating the feasibility of the submarine hull design. Nuclear submarine technology is complex, involving thousands of supporting systems and equipment. To rationally arrange the tens of thousands of devices, instruments, and accessories inside the submarine, Huang Xuhua continuously adjusted, modified, and refined the layout, ensuring that the kilometers-long cables and pipelines were properly positioned, making it possible to shorten the construction period. Huang Xuhua said: "In the construction of the 'Project,' we made several innovations compared to the U.S. and the Soviet Union. Unlike the U.S., China's nuclear submarines—from the hull design to the nuclear reactor—were achieved in one step, entirely the result of independent innovation. From design, construction, and assembly to the installation of the nuclear reactor on the submarine, we forged our own path. Unlike the Soviet Union, which first tested nuclear reactors on large surface icebreakers, allowing them to disregard reactor size constraints—they developed the 'Lenin' atomic icebreaker first and then transferred the reactor technology to submarines. Since the reactor of the Soviet Union's first nuclear submarine was an improved version of the 'Lenin' icebreaker's reactor, it suffered from inherent flaws. Although their nuclear submarines boasted the 'largest' tonnage in the world, excessive tonnage is not advantageous—it compromised the mobility and stealth of the nuclear submarine."

Using the most "down-to-earth" methods to solve the most advanced technical problems is the secret weapon of Huang Xuhua's team in overcoming difficulties. It is precisely this spirit of independent innovation that inspired Huang Xuhua and his team to combine nuclear power with a teardrop-shaped hull in one step, developing China's teardrop-shaped nuclear-powered submarine.

From [Month] to [Month], China's "Long March –" nuclear submarine conducted its first deep-water test in the South China Sea. The so-called deep-diving limit test for nuclear submarines primarily examines their overall performance and combat capabilities, including deep diving, full underwater speed, and deep-water torpedo launches. After becoming the second chief designer of the nuclear submarine, Huang Xuhua was deeply concerned about the deep-diving limit test. He said: "Since the delivery of China's first nuclear submarine to the Navy in [Month] [Year], deep-diving tests had not been conducted due to various reasons. From the perspective of military equipment research, development, and construction, the nuclear submarines we delivered to the military had not undergone deep-diving tests, which means they could not be considered finalized equipment. In a strict and scientific sense, they were not ready for active service. Therefore, the deep-diving limit test for nuclear submarines is essential to evaluate our overall design, particularly the hull structure—whether it can withstand seawater pressure, meet design standards, and fulfill the requirements for active service. There must be absolutely no ambiguity regarding the deep-diving limit test."

During the deep diving process of a nuclear submarine, any structural strength or sealing performance that does not meet the requirements could potentially lead to "submarine destruction and loss of life" under the immense pressure of seawater. "Some test participants feared they might not return, perishing at the bottom of the sea; a few even sent letters to their loved ones, stating that if they did not return from the mission, there were certain matters they wished to be handled on their behalf. This was essentially a 'farewell letter'," Huang Xuhua recalled with a grave expression. "At that time, I said one thing, I told them to rest assured, that I would go down with them. As soon as I said this, the entire atmosphere changed immediately. They thought, as the chief designer, who was already of a certain age, if I dared to go down with them, what reason was there to worry? Seeing the shift in everyone's mood, I then said that we were not asking for sacrifices, but for a deep dive to retrieve all the necessary data. We should be singing 'Valiantly, with high spirits, crossing the Yalu River...' and dive down singing this song."

Thus, inspired by Huang Xuhua, many stepped onto their testing posts with high spirits. According to records, to ensure safety, the deep-dive test leadership team decided to proceed step by step, advancing gradually from shallow to deep depths, conducting the trials in stages. Initially, two trial dives were carried out. **First Voyage: Preliminary Dive** On [date] at [time], the nuclear submarine left port and sailed [distance] nautical miles into the test area. It submerged at [time] on [date], reaching an actual depth of [depth] meters. Throughout the test, the atmosphere was extremely tense, with all personnel meticulously recording various measurements. This preliminary dive confirmed correct command and operation, with all mechanical equipment functioning well. Data was successfully collected from all monitoring stations, and valuable experience was gained. An issue with the hull strain measurement system—where external strain gauge readings were excessively high—was resolved by implementing shielding and compensation measures. **Second Voyage: Deep-Dive Test** Given the high risks involved in this test, it was decided after deliberation that personnel would accompany the submarine during the deep dive. Deputy Commander Wang Shouren took command aboard the vessel, with Huang Xuhua, Wu Tingguo, and Xu Binghan serving as technical leads.