The Marine Department will look into whether the embankment which the ill-fated ferry hit in Ayuttaya, resulting in the drowning of 28 passengers, was properly designed and built.
Department deputy director-general Nat Chabchai said officials have set up a panel to look into the boat tragedy in the Chao Phraya River.
Apart from the condition of the boat and the behaviour of the helmsman, the panel will investigate if construction of the concrete embankment was legally permitted, and whether it was properly designed and built.
The embankment is along the banks of the river at Wat Sanam Chai in Ayutthaya, where the boat tragedy occurred.
The embankment is three metres high and 32 metres long, with its base submerged one metre below the river, Mr Nat said.
The investigation would be concluded in 10 days, he said.
Witthaya Yamuang, director of the Marine Office 2 in Ayutthaya, said the size of the hole in the Sombat Mongkolchai Tabtim's hull clearly showed it hit a solid object underwater. It also testified to the helmsman's recklessness.
The double-decker boat was overloaded and accelerating to overtake a sand barge at a curve in the river, he said.
The helmsman was attempting to overtake on the right-hand side of the barge, where there was only a small clearance to the bank.
The waves pushed the boat hard towards the bank and the driver lost control, Mr Witthaya said.
The ferry hit the concrete embankment at Wat Sanam Chai in Phra Nakhon Si Ayutthaya district. The rupture to the right side of the hull was 9.6 metres long, letting water into the boat.
The boat was licensed to carry 50 passengers but was actually carrying more than 150 Muslims who were returning home after attending an an annual religious ceremony at a local mosque in Ayutthaya province when it hit the embankment on Sunday afternoon.
Pol Col Thanasak Panyaem, deputy Ayutthaya police chief, said the damage to the boat was evidence of the recklessness of helmsman Wirach Chaisirikul.
Police have charged him with recklessness causing death and injuries, steering an overloaded boat, and having an expired boat licence.
Sunthorn Phansuethong, the boat owner, yesterday reported to investigators, but no charges have been laid against him yet, Pol Col Thanasak said.
He said police are questioning Mr Sunthorn and considering whether to bring charges.
Udomsak Khaonuna, an Ayutthaya disaster prevention and mitigation officer, said an initial sum of 38,000 baht will be given to each family of the dead victims.
Mr Sunthorn, the boat's owner, also gave 10,000 baht to each of the 28 families of the dead victims, Mr Udomsak said.
Tourist boats in Ayutthaya have been affected by Sunday's tourist boat capsize as passengers have cancelled their reservations, resulting in damages estimated at 1 million baht.
Thanakrit Kittithammakul, president of the Ayutthaya's Tourist Boat Club, yesterday revealed that members of the club which operate almost 30 tourist boats in the central province have been heavily affected by the tragedy, as it has put people off travelling on tourist craft.