A Pandaw River Expeditions river cruise boat sank in heavy seas off the Malaysian coast as it was being toed by tug.
The vessel became swamped with water and capsized in heavy seas while being towed from Saigon to Singapore and then on to Yangon.
There was no one on board the RV Saigon Pandaw at the time and no casualties.
The results of an official investigation into the incident on December 21 are still awaited.
The vessel, to have been renamed the Sagaing, was built three years ago in Vietnam and was on its way to start operating in Burma where demand is high.
Company founder Paul Strachan said: “We have contacted all passengers booked and have the space in other ships to relocate them or if not convenient. Passengers will be refunded the full amounts paid.
“Passengers have been incredibly kind and understanding over this and we are deeply grateful to them for their sympathy at such a time.
“Despite this loss, with two new ships under construction, we at Pandaw still have the capacity to meet growing demand for river expeditions in Burma.”