The newly built vessel was undergoing testing with 25 people aboard in the eastern province of Jiangsu on Thursday afternoon when the accident happened, state media said.
Three people had been rescued, state broadcaster China Central Television reported, leaving 22 missing. The television report said “around” eight foreigners were on board when the boat sank.
A Singapore foreign ministry spokesman told AFP that the vessel, JMS Delta, was registered in the city-state and four of its nationals were on board.
The Japanese and Indian consulates in Shanghai each confirmed to AFP that one of their nationals was among the missing.
A microblog posting by a newspaper under China’s transport ministry said two of the others on board were from Malaysia and Indonesia.
“Water entered the boat cabin very quickly, in less than 20 seconds it was completely filled with water,” survivor Wang Zhenkai told state television from his hospital bed.
Wang was accompanying a Japanese technician who was testing the engine, though the ship was made and outfitted in China, reports said.
A photo carried by state media showed only the bow and part of the hull of the metal ship floating above the waterline, with a salvage barge alongside.
Reports said rescue workers were trying to raise the vessel and the search was continuing, but Xinhua cited rescuers saying the work was difficult as the current was swift and the water cold.
“As long as we have the slimmest hope, we will give a 100-percent effort,” Wang Shiming, deputy head of the Jiangsu Maritime Safety Administration, told state television.
The accident occurred on a stretch of the river between the cities of Jingjiang and Zhangjiagang, which is close to the Yangtze’s mouth near the commercial hub Shanghai.
The provincial government said the boat was undergoing trials without properly completing the required procedures and without first reporting the condition of the ship, as required by regulations.
The operator “should have reported to the responsible government body for endorsement, but did not,” Wang, the safety administration official, said. (AFP)