A cement-laden vessel capsized in the Pandob river of the district's Bakerganj upazila on Thursday night, police said.
Bakerganj Police Station officer-in-charge Alauddin Milon said the vessel left Barishal with 1,000 sacks of cement at night.
Read: Trawler capsizes off Chandpur
"When the trawler reached the Kheyaghat area of Kaloskathi union, it collided with the bulkhead of another vessel coming from the opposite direction and sank," he said.
However, the skipper of the vessel and his associate managed to swim ashore. "One of them, named Ripan, was injured and admitted to Bakerganj Health Complex," the officer said.