On July 7, 2010, a barge being propelled by a tug boat collided with a tour boat that had dropped anchor in the Delaware River. As a result of the collision, two passengers on the tour boat were killed and twenty-six were injured. The tour boat sank in 55 feet of water.
Detail regarding the incident has just been released in an updated NTSB report. We can use the information about this report to begin a Cause Map, or visual root cause analysis. The information in the report can also point us in the direction of important questions that remain to be answered to determine exactly what happened and, most importantly, how incidents like these can be prevented in the future.
In this case, a tour boat had dropped anchor to deal with mechanical problems. According to the tour boat crew’s testimony and radio recordings, the tour boat crew attempted to get in touch with the tug boat by yelling and making radio calls. Neither were answered or apparently noticed. The barge that was being propelled by the tug boat crashed into the tour boat, resulting in deaths, injuries and loss of the tour boat.
The lookout on the tug boat was inadequate (had it been adequate, the tug boat would have noticed the tour boat in time to avoid the collision). The report has determined that the tug boat master was off-duty and below-deck at the time of the collision. According to cell phone records, the mate who was on lookout duty was on a phone call at the time of the collision and had made several phone calls during his duty. The inadequate lookout combined with the inability of the tour boat to make contact with the tug boat resulted in the collision.
There are two obvious areas where more detail is needed in the Cause Map to determine what was going on that led to the issues on the tug boat. Specifically, why was the lookout on the cell phone and why wasn’t the tour boat able to contact the tug boat through the radio? Because of the strict requirements for lookouts on marine duty, there is also an ongoing criminal investigation into the lookout’s actions. When the final NTSB report is issued, and the criminal case is closed, these questions should be answered. More detail can be added to this Cause Map as the analysis continues. As with any investigation the level of detail in the analysis is based on the impact of the incident on the organization’s overall goals.