What caused Da Nang cruise ship tragedy?

By Tien Thanh   June 6, 2016 | 05:20 pm GMT+7
The ship's capacity was 28 but it was carrying 56 people, including crew members. Passengers gathered on one side of the ship to enjoy the view of the Han River at night caused the ship to list and eventually go down.
What caused Da Nang cruise ship tragedy?