Zhang Shengwu is 60 years old, he is a farmer and has not studied naval engineering, although throughout his long life he has had other jobs that can be assumed to be a handyman, such as a carpenter, welder or in the shipping industry. Back in 2014, Shengwu saw a person on TV building his own submarine and, just like you and I ventured to make a cod pil-pil after seeing Argiñano do it effortlessly (spoiler: it goes wrong), the farmer made the determination to build it for himself.
As China Daily tellsnot even his family’s warnings about the risks or the cost stopped him. Just over a decade later, in early July 2025, Zhang Shengwu showed the world his creation with a successful test dive of his “Big Black Fish”, a homemade submarine weighing five tons capable of submerging eight meters, the latest of his creations. It is neither the first submarine he has made nor is it almost certainly the last.
Some play petanque, I make submarines. The idea of building a submarine from scratch caught his attention, so he invested 5,000 yuan (approximately 642 euros at the exchange rate) to buy sheet steel, a motor and a battery. In about six months he had built his first prototype, a submarine six meters long, 1.2 meters high, weighing two tons, how Sixth Tone collects. The bad news is that there was a leak. The good news is that the design of its prototype obtained a patent, a formal recognition by the Chinese state of the technical validity of the project.
Obviously it didn’t stop there. He then built a surface ship that also got a patent. As Shengwu himself acknowledges, his head is never idle, so he already had the following project in mind: invested 40,000 yuan (just over 5,000 euros) to create the second generation of his submarine, which would later become the Big Black Fish.
First submarine built by Zhang Shengwu. CCTV News
His masterpiece: he Big Black Fish. He improved and lengthened the hull to seven meters and 1.8 meters high, so that its cabin now seats two people. For more stability, Zhang poured approximately two tons of concrete into the hull as a counterweight and mounted two ballast tanks at the bow and stern: “The tanks collect water to submerge and empty it to float,” explains for Sixth Tone. He didn’t want any more leaks like his previous project, so he welded every joint and installed circular hatches.
This boat is capable of reaching speeds of up to four knots and Zhang is especially proud of its performance. So, details that “a small battery and a motor can propel this huge structure underwater. And it can submerge for half an hour without a single drop of water entering, it can even recoil.”
Context. For someone to assemble something as complex and unintuitive as a submarine at home sounds exotic, but the reality is that in China it happens relatively often: in 2009 another inventor named Li Yuming Up to five homemade submarines were manufactured. In 2014 a former prison officer named Zhang Junlin He also developed a tourist submarine that he tested in the South China Sea. In 2015, a Shaanxi villager He borrowed 200,000 yuan to make a 9.2-meter one.
Why is it important. It is no coincidence: the Chinese government has been betting on rural talent for years. Thus, in 2020 was fixed The goal is to have one million “innovation leaders” and 15 million entrepreneurs in rural areas by 2025. In fact, in Anhui, the province where Zhang Shengwu and the prison officer – inventor come from, these profiles can qualify for a one-time initial subsidy of 5,000 yuan if their activity remains stable for more than six months.
Shengwu fits that profile: without a college degree but with a lot of time and persistence, he has successfully executed complex technology. Obviously not at the level of the Chinese army and its submarinesbut in a functional way: it submerges, navigates and rises. AND already have His next submarine in mind, the third: it will be larger and with more autonomy.
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Cover | CCTV and Gemini
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