Huang Xuhua, chief designer of China's first-generation nuclear submarines, died on Thursday evening in Wuhan, Hubei province. He was 99.

Born in March 1926 to a family of doctors in Guangdong province, Huang was the third child of his parents.

After spending his boyhood in wartime, he joined Shanghai Jiao Tong University to study shipbuilding. During the years at the university, the young man was exposed to strict academic training and learned about the communist revolution. He joined the Communist Party of China in April 1949, right before his graduation. After receiving his bachelor's diploma, Huang started his lifelong career in China's shipbuilding industry. In 1958, Huang was selected to join the research team tasked with designing China's first nuclear-powered submarine.

At the beginning of the design work, Huang and his colleagues found that China lacked the basic conditions to develop such a sophisticated hardware technology at that time.

None of the researchers had any knowledge in that field, and since other countries were extremely protective of such technologies, they barely had any technical reference materials.

Huang and his colleagues started by scouring newspapers and magazines for information.

"It was extremely difficult to find a little piece of information," the researcher recalled in 2020. "The information was either too fragmented or hard to tell whether it was true or false."

They finally came up with five plans after piecing together all the information they found and carefully analyzing and studying two US submarine models.

The team members didn't have any computers or digital calculators, so they used abacuses and rulers to solve problems. To ensure accurate calculation results, they were divided into three groups to do the math at the same time and would recalculate if the three values reached were not the same.

Their work continued, despite the project was suspended from 1962 to 1965, when China was reeling under economic difficulties.

In the following years, Huang and several other top engineers led the research and development for the nation's first-generation nuclear submarines, the Type 09I nuclear-powered attack submarine and Type 09II nuclear-powered ballistic missile submarine.

After years of painstaking efforts, China finally built its first nuclear-powered submarine — the first Type 09I — in 1970, becoming the fifth nation to have such hardware.

Huang's name remained classified until 1987 when a magazine in Shanghai was allowed to publish a report on him, which only disclosed his family name of Huang.

Even in his 90s, the designer used to visit his office at the Nuclear Submarine Institute in Wuhan every weekday morning to review and compile materials of his know-how and experience, and would also counsel young researchers on technical issues.

The first product of Huang and his colleagues — a Type 09I nuclear-powered attack submarine — is now on display at the PLA Naval Museum in Qingdao, Shandong province, after more than 40 years of service.

Due to his outstanding contributions, Huang was given the Medal of the Republic, China's highest honor, in 2019.