From Cultivating the Field to Sailing Underwater: The Journey of Zhang Shengwu
An Unexpected Inventor
Zhang Shengwu, a 60-year-old Chinese farmer, has become an astonishing figure in the world of homemade technology. Despite not having formal training in naval engineering, Zhang’s background as a handyman—combined with experience in carpentry, welding, and the shipping industry—has uniquely positioned him to venture into the realm of submarine construction. It all began in 2014 when he watched a program showcasing an amateur submarine builder. Inspired, he resolved to create his own model.
Defying Doubts and Risks
His family cautioned him about the risks and expenses involved, yet Zhang’s passion was unwavering. By July 2025, he unveiled his latest creation, the “Big Black Fish,” a five-ton submarine capable of submerging up to eight meters. This accomplishment highlights not only his determination but also the growth of his skills over a decade of innovative tinkering.
The First Prototype
Some might enjoy leisurely activities, but Zhang found joy in building submarines. Investing around 5,000 yuan (approximately €642), he acquired materials like sheet steel, a motor, and batteries, which allowed him to construct his initial prototype: a six-meter long submarine weighing two tons. Although this maiden attempt encountered a leak, it was significant enough to secure a patent, validating his design.
A Journey of Improvement
Zhang didn’t stop at his first attempt; he went on to build a surface vessel that also received a patent. An inventive mind like Zhang’s is never at rest, and he promptly began work on a second-generation submarine, investing 40,000 yuan (over €5,000), leading to what would become the “Big Black Fish.”
Image: First submarine built by Zhang Shengwu. Source: CCTV News
The Masterpiece: Big Black Fish
The Big Black Fish is a remarkable achievement, measuring seven meters long and 1.8 meters high, featuring a cabin that seats two people. To enhance stability, Zhang added approximately two tons of concrete into the hull as a counterweight and incorporated ballast tanks in both the bow and stern. These tanks are designed to collect water for submersion and expel it for flotation.
Essentially, this submarine can reach speeds of up to four knots, and Zhang takes pride in its performance. He reveals that a small battery and a motor can nudge this massive structure underwater for up to thirty minutes without a single drop of water seeping inside.
A Culture of Innovation in China
While Zhang’s homemade submarine may sound exotic, individual inventors creating functional submarines is not rare in China. Previous stories include a former prison officer who built a tourist submarine and various other local inventors who have ventured into underwater exploration.
Supporting Local Innovators
The Chinese government has long been committed to promoting rural innovation. By 2020, initiatives aimed at fostering one million “innovation leaders” and 15 million entrepreneurs in rural areas were established. Zhang’s story exemplifies this, as he represents a new wave of inventors who, despite lacking traditional qualifications, are pushing boundaries and finding success through persistence and creativity.
Looking Ahead
With ambitions set high, Zhang has plans for a new, larger submarine with enhanced autonomy. His journey from farmer to submarine builder serves as an inspiration for aspiring makers everywhere, showcasing that with effort and creativity, anyone can navigate the waters of innovation.
In conclusion, the tale of Zhang Shengwu is not just about a farmer making submarines; it illustrates resilience, creativity, and the spirit of innovation thriving in the most unexpected places.