{"id":5998,"date":"2026-07-06T09:30:00","date_gmt":"2026-07-06T14:30:00","guid":{"rendered":"https:\/\/okdiario.com\/techy\/en\/?p=5998"},"modified":"2026-07-06T05:57:13","modified_gmt":"2026-07-06T10:57:13","slug":"a-chinese-farmer-in-his-60s-built-an-11000-pound-homemade-submarine-in-his-village-and-launched-it-into-a-river-in-anhui-as-if-it-were-an-impromptu-naval-test","status":"publish","type":"post","link":"https:\/\/okdiario.com\/techy\/en\/a-chinese-farmer-in-his-60s-built-an-11000-pound-homemade-submarine-in-his-village-and-launched-it-into-a-river-in-anhui-as-if-it-were-an-impromptu-naval-test\/5998\/","title":{"rendered":"A Chinese farmer in his 60s built an 11,000-pound homemade submarine in his village and launched it into a river in Anhui, as if it were an impromptu naval test"},"content":{"rendered":"\n

Imagine walking by a rural river and watching a black steel cylinder slip under the water like something from a shipyard test range. <\/p>\n\n\n\n

That is what happened in Anhui, China, where Zhang Shengwu, a farmer in his 60s, built a homemade submarine called “Big Black Fish” that can carry two people and dive to 26 ft. The roughly 11,000-lb. vessel drew public attention after a river test in Hanshan County in July 2025.<\/p>\n\n\n\n

This is not a naval breakthrough, and it is not a certified consumer toy. Still, it matters because it puts three big questions in one small cockpit: how far can self-taught technology go, who checks safety when it enters public waterways, and could low-cost underwater machines<\/a> one day help local communities understand the rivers they rely on?<\/p>\n\n\n\n

A river idea becomes steel<\/h2>\n\n\n\n

Zhang did not come from a university lab. He grew up around boats in Zhangdu village, worked as a carpenter, welder, and in shipping, and later built a sand and gravel wharf where he watched cargo vessels move along the water every day.<\/p>\n\n\n\n

The idea took shape in 2014 after he watched a television program about a self-made submarine. “If others can do it, why can’t I?” he recalled, according to People\u2019s Daily Online. That little question became a decade-long project.<\/p>\n\n\n\n

\n
\n
\n

Also Read: California’s bullet train is no longer the project voters approved in 2008, and the gap keeps getting wider<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n

His first attempt was modest but serious. He spent about $700 on steel plates, batteries, and an engine, then built a prototype about 20 ft. long, about 4 ft. tall, weighing roughly 4,400 lbs. It leaked underwater, but it still earned him a utility model patent<\/a>.<\/p>\n\n\n\n

What Big Black Fish can do<\/h2>\n\n\n\n

The second-generation vessel is far more ambitious. China Daily reported that Zhang invested more than $5,570 into the newer submarine, which has room for two people and can travel at about 4.6 mph underwater.<\/p>\n\n\n\n

Mechanically, Big Black Fish works through a familiar submarine principle. Water enters ballast tanks so the vessel loses buoyancy and sinks, then drains out so it can return to the surface. Zhang also added about 4,400 lbs. of concrete to the bottom to improve stability.<\/p>\n\n\n\n

The power system is also simple. Zhang said a small battery and an electric motor can push the heavy craft underwater, and he noted that it can stay submerged for about half an hour without leaking. It can even reverse, a small detail that matters when a machine is moving in a narrow river instead of open water.<\/p>\n\n\n\n

\"Zhang
After a decade of development, farmer Zhang Shengwu successfully piloted his 5-ton, battery-powered submarine in a public river trial.<\/figcaption><\/figure>\n\n\n\n

Why pressure matters<\/h2>\n\n\n\n

A 26-ft. dive may sound shallow compared with military submarines or deep-sea research vehicles. But water pressure builds quickly<\/a>, and the National Oceanic and Atmospheric Administration (NOAA) explains that for every 33 ft. of depth, pressure increases by one atmosphere. <\/p>\n\n\n\n

That is why welds, hatches, seals, batteries, and emergency systems are not minor details.<\/p>\n\n\n\n

Zhang appears to understand at least part of that challenge through hands-on experience. China Daily reported that he reinforced weld points and used silicone and adhesive to improve the watertight sealing. Still, the public reports available so far do not describe a formal safety certification for Big Black Fish.<\/p>\n\n\n\n

That is where the wonder of the story gets complicated. A homemade submarine can inspire people, especially children who love machines, but underwater travel<\/a> leaves very little room for error. One weak seal can turn a clever invention into a very dangerous ride.<\/p>\n\n\n\n

Rural innovation, not a war machine<\/h2>\n\n\n\n

The striking part of Zhang\u2019s story is not only the submarine, it is where it came from. Big Black Fish was not born in a defense contractor\u2019s workshop or a coastal engineering school, but in a rural setting where tools, patience, and local river knowledge did much of the work.<\/p>\n\n\n\n

\n