What Happened
What Happened
On November 19, 2016, the fully-laden bulk carrier Nenita, registered in the Marshall Islands, was outbound on the Columbia River when the vessel suffered an engine failure impacting its ability to maneuver. The vessel subsequently ran aground at Three Tree Point on the Washington State side of the river, damaging its bulbous bow and hull. After the grounding, the Nenita was towed to Longview, Washington, for temporary repairs. Two weeks later, the vessel resumed the voyage to its original destination. There were no injuries or reported pollution as a result of the accident.
What We Found
What We Found
The probable cause of the grounding of the bulk carrier Nenita was the failure of a main engine cylinder cooling jacket that initiated an automatic reduction in engine speed, resulting in the eventual loss of steerageway. Contributing to the accident was the lack of information relayed from shipboard personnel to the pilot about the status of the main engine, which prevented him from taking effective corrective action following the engine casualty.
What We Recommended
Water Chemistry
Maintaining proper water chemistry in engine cooling water systems reduces corrosion, scale, and the formation of deposits, which ensures effective cooling (heat transfer) to satisfy the system’s operating requirements. Mariners should conduct testing per the manufacturer’s recommended schedule, ensure levels of treatment are correct, and maintain water quality within specified limits. Insufficient cooling water maintenance may result in increased corrosion, clogging of cooling water passages, or, ultimately, the failure of equipment.
Tightening of Fasteners
Over the last two years, the NTSB has investigated three separate accidents that may have been caused by a failure to tighten fasteners on marine engines to the manufacturer’s recommended torque settings. Undertorqueing a fastener may cause excess vibration or allow the fastener to come loose, while overtorqueing may lead to failure of the fastener or the machinery component being secured. When installing fasteners, mariners should use a calibrated torque wrench and follow the manufacturer’s recommended tightening guide and torque values.
