Chinese farmer Zhang Shengwu successfully conducted a river trial of a homemade submarine in Hanshan, eastern Anhui Province, state broadcaster CCTV reported. The 60-year-old former carpenter piloted the craft, nicknamed “Big Black Fish,” during Thursday’s debut after two years of construction. The seven-metre, five-ton vessel seats two people, can dive to about eight metres, remain submerged for roughly 30 minutes and cruise at around four knots on battery power. Zhang said he spent about 45,000 yuan ($6,200) on steel plates, engines, ballast tanks and other materials after earlier prototypes leaked. China has seen several grassroots submarine projects in recent years, reflecting a culture of do-it-yourself engineering despite limited resources. Zhang now plans to design a larger model, although the homemade craft remains a personal venture unrelated to commercial or military programs.