Meanwhile, the victim whose leg was nearly sliced completely through has since had it amputated and been flown to Bangkok for further treatment.
Pol Col Sompong Tiparpakul, chief of Muang Krabi Police Station confirmed that Adisorn Benmamud, 27, has initially been charged with careless driving causing injury. However, additional charges could be added if it is found that he and the boat do not have proper licences.
Sergei Dmitriev, 30, and Dmitry Kuryanov, 48, were struck by the propeller of the speedboat Sunsan 2 when they resurfaced from their dive at Maya Bay at about 10:30am, said Nitiphat Mongkolpradit of the Krabi Tourist Rescue Centre. (See story here)
Mr Dimitriev had his right leg cut off from the knee down, and all toes on his left foot were also severed in the accident.
The Russian embassy today (Feb 4) sent a chartered flight with medical personnel on board to transport Mr Dmitriev from Bangkok Phuket Hospital to Vejthani Hospital in Bangkok for further treatment. He was reported to remain in a critical condition.
Mr Kuryanov suffered three major lacerations and a fractured bone in his right calf. He remained in Krabi hospital.
Benmamud told police that he had more than 30 passengers on board the Sunsan 2 yesterday and that when he came to the entrance to Nang Bay he felt that he had hit something so reverse the boat. He noticed the oxygen tank floating to the surface then saw blood and the two injured divers so contacted local officials for help.
He insisted that the area is the route that boats use to travel in and out of Maya Bay and that it is not usually an area where people swim, police have said.
Additional reporting Eakkapop Thongtub and Bangkok Post.