The wreck of the "Phoenix" tour boat that sank off the coast of Phuket in July this year killing 47 Chinese holidaymakers was finally lifted up, four months after the tragedy happened.

A recovery ship with a heavy-lifting crane was brought from Singapore to raise the sunken vessel from the seabed – after earlier attempts to bring the ship back to surface using tanks and air-filled balloons failed.

Investigators will now examine the boat to try to find out what is the cause behind one of the country's worst maritime disasters.

More than 100 people were on board when the boat capsized during a sunbathing and snorkeling day-trip in July – almost half of them perished. All were holidaymakers from China.

Storms had been forecast before the boat was out in  to sea. Police will be asking why the owners of the "Phoenix" ignored warnings.

Raising the "Phoenix" was always seen as essential for investigators to understand whether the boat's operators were at fault.

There are questions about the competence of the crew, the vessel's seaworthiness and the effectiveness of life-saving equipment.

The boat's owner, skipper and engineer have all been charged with recklessness causing death.

"We feel great sympathy after what happened," said Maj. Gen. Surachate Hakparn, head of the Thai Immigration Bureau who is overseeing the salvage operation.

"We will examine the boat with transparency to reassure the victims' relatives. We will prosecute anyone found to have done wrong."

During the salvage operation, the Thai diver who first found the wreck – Nipat Kladnack – died after he fell and struck his head. He became the 48th victim of the tragedy.

Anger over the loss of life – and concern about safety – led to thousands of Chinese people cancelling holidays to Thailand.

"The recovery of the boat was completed with cameras recording every procedure to ensure openness," said Hakparn.

"We brought the recovery crane from Singapore, if we were not determined to carry out a full investigation we wouldn't have invested so much."

Following the tragedy, the Thai government carried out inspections of 400 tourist boats operating at Phuket – half were found to not meet required safety standards. Thirty were immediately ordered out of the water.

Officials are promising tougher regulations – in the future, boats will have to register their departure and arrival times and the number of passengers on board, much like an airplane's flight plan.

But tourism chiefs know a great deal will need to be done to win back confidence.