I wanna try to guess, listening the voices going around in Rawai area, how the story is putting all the various pieces together:
The long tail was not rowing: how could it have been off Ko Bon? in fact, as you can see from the photos, at the stern there is the engine housing (the hole). Engine that in the accident fell into the water.
The long tail was trolling probably at about 4-5 knots on parallel route of the Robalo fishing boat. The old pilot (listening to gossip) is almost totally deaf and sees little: that's why the boat captain's driving license has expired and never renewed and the boat (which at the origin was equipped with the classic engine) is not even registered, so even not insured.
Robalo boat was going on straight route from Chalong to Racha at about 18 knots. The captain has a regular Thai boat driving license and also as a shipboard engineer. The boat is regularly registered and insured.
It seems that suddenly the long tail turns crossing the path of the Robalo that slows down instantly and turns to starboard.
Following the clash that was not strong, given the minimum damage reported by the two boats, the long tail engine and the pilot fall into the water. Probably the head of the long tail pilot was hit by some parts of the motor.
The pilot of the Robalo immediately throws itself into the water to recover the body of the long tail pilot that, despite not having obvious wounds, does not regain consciousness
The Captain of the Robalo repeatedly calls the MayDay by radio without receiving any response and then decides to immediately return the long tail pilot to Chalong while alerting the ambulance by mobile.
People say that Chalong police, however not competent, has never questioned the pilot of the Robalo
The competent maritime police of Chalong has already questioned the pilot of the Robalo, putting everything on record
Someone says that the scientific (forensic) police have already inspected the boats, reporting that the impact, given the minimum damage, was not violent, so the Robalo had already visibly slowed down.
It seems that the family of the deceased, with the police mediation, had initially agreed for 1.2 million of bath (no one can feel good about his conscience even if death is accidental) . Later, in the face of a higher demand (voices say that family raised the amount to 1.3 mln) despite the agreement reached, the matter passed to the lawyers on the advice (it seems) of the police itself .