The 32 meter long, 203 dwt tug Ava Payagua collided with the 82 meter long sand-barge Rio Turbio on the Parana River off the 102 kilometer mark near Zarate, Argentina .   The Ava Payagua was undamaged, but the Rio Turbio quickly capsized and sank.   No reports of injuries to the 12 crew on board the Ava Payagua.   Authorities launched multiple vessels on scene conducting search and rescue for the missing men.  Divers were sent into the vessel and found one survivor.   One engineer was found alive in the capsized hull and was taken to hospital suffering from hypothermia.  Divers later found four bodies trapped in the hull.   Divers continue to search for three missing crewmen.   Authorities placed a boom was placed around the Rio Turbio to contain any pollution that may be released.   Reports state three crew from the Ava Payagua were taken into custody while the vessel was being detained for inspection.   An investigation into the incident is being conducted.