There were 22 persons aboard the TONKAWA at the time of capsizing; 11 persons survived the casualty and 11 persons lost their lives. The National Transportation Safety Board determines that the probable cause of the capsizing was the failure of the rig crew to close the No. 3 starboard ballast inlet valve properly, which resulted in the accidental flooding of the No. 3 starboard ballast tank with an attendant loss of stability of the drilling barge. Contributing to the accident was the failure of the person-in-charge of the drilling barge to supervise the ballasting operation properly and to ascertain that the rig personnel assigned to the ballasting operation understood the system.
Marine Accident Report - Capsizing and Sinking of the Drilling Barge TONKAWA in Bayou Chene near Morgan City, Louisiana, May 20, 1985
1986
35 pages
Report
No indication
English