Alcohol and “Power Distance” Led to Nippon Maru Allision

The National Transportation Safety Board (NTSB) has released a Marine Accident Brief about a December 30, 2018, accident involving the passenger ship Nippon Maru which struck mooring dolphins at a U.S. Navy fueling wharf in Apra Harbor, Guam.

The vessel was maneuvering in a turning basin after getting under way from the harbor’s commercial port. No pollution or injuries were reported, but damage to the vessel was estimated at $456,080, and damage to the mooring dolphins was in excess of $500,000.

The NTSB determined that the probable cause of the incident was alcohol impairment of the master while he conned the vessel, resulting in an errant astern engine input.

The master stated that while he and the pilot attempted to pivot the vessel in the turning basin, he had mistakenly moved the joystick that controlled the Nippon Maru’s engines and rudder to the astern position. Statements from the third officer and bridge wing VDR audio recorded during the accident sequence confirm that the master moved the joystick astern, eventually moving it to full astern, and kept it there until after the vessel struck the mooring dolphins.

To stop the sternway of the Nippon Maru as it began its turn, the pilot requested dead slow ahead and then half ahead on the vessel’s engines. As the vessel continued to close on the mooring dolphins, more drastic engine orders, such as engines full ahead, would have been expected to avoid contact. However, given that the master had mistakenly moved the engines to astern while intending to go ahead and ignored warnings from the third officer, it is unlikely that requests from the pilot to further increase ahead propulsion would have changed the outcome of the accident.

The pilot’s orders to the tugboat Talofofo to increase astern propulsion, which were intended to increase the swing of the ship, were insufficient to counteract the sternway generated from the errant engine and rudder input from the master.

Alcohol consumption

The master reported that he drank one and a half cans of whisky and soda three to four hours before the accident. He also reported that he drank one can of beer two to three hours after the accident. The master was documented as having a blood alcohol concentration (BAC) of 0.071 g/dL approximately five hours after the accident, and therefore it is likely that he consumed more alcoholic beverages than he reported, states the NTSB. The Coast Guard maximum allowable BAC is 0.04 g/dL, and the company policy is less than 0.03 g/dL while on duty.

Because the breathalyzer test was conducted five hours after the incident, it is possible that his BAC was the result of additional alcohol consumed after the accident. However, the master’s errors in maneuvering the vessel were not consistent with his level of skill and experience—in particular his experience with this vessel in this harbor—and suggest that he was impaired during the vessel’s voyage. Also, the pilot noted that the master smelled of alcohol just after the accident. 

A BAC between 0.06 and 0.15 g/dL is associated with memory, attention, coordination and balance impairments. Given the evidence, the NTSB states that it is likely that impairment from alcohol contributed to the accident.

Master/Pilot Exchange

According to the pilot, a master/pilot exchange was normal practice on the ships that he piloted, but an exchange was not conducted on the Nippon Maru prior to getting under way for the accident voyage. The master arrived on the bridge minutes before the ship began singling up lines in preparation for getting under way, and no information was discussed other than which direction the vessel would turn. A proper master/pilot exchange would have allowed the pilot and master to talk through the expected actions of the master and the operation of the joystick controller.

Furthermore, interaction with the master during a master/pilot exchange would have given the pilot an opportunity to discover that the master had been drinking, and, if he believed it necessary, an alternate arrangement could have been made to ensure that the Nippon Maru was operated safely.

Language Barrier

According to the Nippon Maru’s deck log, the working languages of the vessel were Japanese and English, and throughout the accident sequence, the master and pilot communicated in English, while nearly all other shipboard communications were conducted in Japanese. Thus, the pilot was not aware of the distances to the mooring dolphins being reported by the second officer on the stern. Although the pilot received distance reports from the tugboat Talofofo captain, he was not able to understand the additional distance information being provided by the crew, which would have corroborated the information provided by the tugboat. 

Furthermore, the pilot was not able to understand the third officer’s first two warnings that the master had the joystick controller in the full astern position. It was only the final warning, five seconds before impact, that was spoken in English. Additionally, the pilot reported that during the accident sequence, the master did not acknowledge his engine orders verbally, and thus he could only assume that the master was complying. These factors suggest that communication between the pilot and crew was ineffective during the accident voyage.

Power Distance

The ability to effectively challenge the actions of another bridge watchstander when an unsafe condition exists, an essential element of bridge resource management, is more difficult when there is a large gap between levels of authority in bridge watch team members. This gap, known as “power distance,” can lead senior personnel to disregard valid challenges by junior personnel. 

Prior to the Nippon Maru striking the mooring dolphins, the third officer warned the master three times that he had the joystick in the wrong position, yet the master ignored each of these warnings and kept the joystick astern. When the third officer attempted to take physical control of the joystick and moved it ahead, the master rebuffed him and moved the joystick back astern. The third officer was the most junior deck officer on the ship, with only a fraction of the master’s seagoing experience.

Additionally, he stated that his relationship with the master was poor, and the master refused to be briefed by the third officer prior to getting under way. It is possible that a large power distance between the master and the third officer, exacerbated by the master’s alcohol-impaired state, contributed to the master’s failure to heed the third officer’s warnings, states the NTSB.

The report is available here.