Chinese farmer's homemade submarine causes a stir: Dive 8m, run on battery

(Dan Tri) - A 60-year-old farmer in Anhui province (China) has built a 7m long, 5-ton submarine that can dive 8m deep for 30 minutes.

The personal submarine was inspired by a TV show. The video of the device being tested quickly went viral, attracting millions of views on social media.

On July 17, China Central Television (CCTV) reported on Mr. Zhang Sheng Wu, who had just completed testing his self-made personal submarine.

The boat, named "Big Black Fish", is capable of carrying two people and operating underwater at a maximum depth of 8m.

Homemade submarine of Chinese farmer (Photo: CCTV).

According to CCTV, the boat was tested in a river branch near Mr. Zhang's home. In the video, the boat operates at a speed of about 4 knots (equivalent to 7.4 km/h), using an electric motor and a small battery, allowing it to operate continuously for about 30 minutes before having to surface to recharge.

Mr. Zhang shared that the idea of building a submarine originated from a TV show he watched in 2014. “I thought, if others can do it, I can do it too,” he told CCTV reporters.

Despite his family's objections, he began to learn about submarine structures through books and simple documents, then began to build the first prototype.

The submarine under construction (Photo: CCTV).

The “first generation” submarine was completed in 2016, is 6m long, weighs 2 tons, and can dive to a depth of about 1m. This version has been patented by the Chinese Intellectual Property Office. The initial manufacturing cost is about 5,000 yuan (about 17 million VND), mainly used to buy steel, engines, batteries and basic equipment.

Upgraded version and online community reaction

Not stopping there, Mr. Zhang continued to invest another 40,000 yuan (about 137 million VND) to upgrade the boat to the second version, “Big Black Fish”. This version is 7m long, weighs 5 tons, uses a reinforced steel frame, has an additional navigation system and a compartment large enough for two adults.

The device is designed for short-term operation in shallow water environments, without pressurization or oxygen regeneration systems, so is only suitable for small-scale testing.

The video recording the submarine testing process quickly became famous (Photo: CCTV).

Soon after the video of the submarine test was posted on Douyin (the Chinese version of TikTok), it quickly went viral and attracted widespread attention. Many netizens praised Mr. Zhang's perseverance, while others expressed concerns about the safety of the device.

According to experts, submarines are complex technical vehicles, requiring factors such as pressure balance, ventilation systems, troubleshooting and seawater-resistant materials.

Homemade submarines are not uncommon in China, but most of these products are only for performance or personal research purposes and do not meet industrial safety standards.

From a technical perspective, Dr. Li Wei, a lecturer in Marine Engineering at East China University of Science and Technology, said: “At depths below 10 meters and in a still freshwater environment, such devices can operate if they are well sealed and weight controlled. However, the risk is still very high without a suitable escape system and pressure sensor.”

Mr. Li also said that local authorities need to have a mechanism to monitor and evaluate the safety of homemade equipment related to water transportation, especially personal submarines, to limit the risk of accidents during operation.

Mr. Zhang has not yet announced plans to commercialize the product, but said he will continue to improve the design and may develop a larger version in the future. However, there is no official information about large-scale testing or support from professional technical organizations.

Source: https://dantri.com.vn/khoa-hoc/tau-ngam-tu-che-cua-nong-dan-trung-quoc-gay-sot-lan-8m-chay-bang-pin-20250719092141691.htm