The ship, Bach Dang, drifted into waters off Hon Rom - Mui Ne in the south central Binh Thuan Province on its way to carry fly ash from Vinh Tan 2 thermal power plant in the province to the southern province of Ba Ria-Vung Tau.
Rescue forces mobilized canoes, fishing boats and water scooters as soon as they received an SOS from captain Nguyen Duc Trung saying the boat was in rough waters. The seven people on the ship were safely brought ashore in about an hour.
Binh Thuan border guards said the ship was hit by waves of up to 1.7 meters high.
After the incident, authorities tightened their monitoring of the Mui Ne area, watching out for eventualities like oil spills. The ship was sailing with 8,000 liters of oil.
According to the Vinh Tan 2 thermal power plant, Bach Dang is a specialized ship, so there was no fly ash spill when it sank.
Fly ash is a fuel source for the thermal power industry, which plays an important role in electricity production in Vietnam.