An offshore provide vessel (OSV) engine room hearth final yr was brought about when an incorrectly sized bearing led to an engine failure, the National Transportation Safety Board says.
On May 27, 2022, the offshore provide vessel Ocean Guardian was conducting a sea trial in Shilshole Bay in Puget Sound when its no. 3 diesel generator engine suffered a mechanical failure, leading to an engine room hearth that brought about $1.1 million in damages. No accidents or air pollution have been reported.
The full NTSB report notes that the Ocean Guardian, a 260.8-foot-long, steel-hulled OSV, was in-built 2003 because the Ken C. Tamblyn. In March 2020, the vessel was bought by Ocean Guardian Holding and renamed Ocean Guardian; the vessel was operated by Stabbert Maritime Group.
The multi-service vessel was powered by 4 Caterpillar mannequin 3516B 16-cylinder diesel-engine-driven major turbines, every producing 2,669 hp. The major turbines equipped electrical energy for each propulsion motors and {the electrical} system for different vessel companies. For electrical energy whereas moored, the vessel was geared up with a 496-hp auxiliary diesel-engine-driven generator. Two 2,200-hp azimuthing stern thrusters (360° rotatable pods) offered the vessel with propulsion, supplemented throughout maneuvering operations with two bow thrusters (one tunnel and one retractable azimuthing unit). The vessel was outfitted with a dynamic positioning system. which allowed the vessel to carry station when operational.
In August 2021, the Ocean Guardian arrived on the working firm’s shipyard in Ballard, Wash., close to Seattle, for upkeep. During the upkeep interval, a shelter deck was added over the aft working deck, two cranes and an A-frame have been put in, and extra lodging areas have been added to the vessel. In January and February 2022, native factory-trained technicians carried out upkeep on all 4 major diesel generator engines, together with top-end overhauls and bearing inspections and replacements as obligatory.
In May 2022, the crew carried out operational assessments of the engines and propulsion management techniques at diminished hundreds whereas the vessel was moored. In order to carry out full operate assessments of those techniques at underway operational hundreds, the vessel wanted to function in open waters. The working firm scheduled a sea trial throughout the week of May 23 to check the vessel’s engines, propulsion techniques, and automated energy administration system to make sure correct operation.
On the morning of May 27, the captain held a security assembly with the 22 crewmembers and contractors on board and mentioned particulars concerning the sea trial, together with muster areas and tasks within the occasion of an emergency. At 1145, as a result of the vessel’s propulsion system had not been absolutely operate examined, two tugboats towed the Ocean Guardian away from the shipyard and out of the harbor by the Ballard Locks to Shilshole Bay for the ocean trial. About 1245, the captain launched the tugboats and requested that one in all them stay close by to “shadow” the Ocean Guardian; the opposite returned to port.
About 1400, the crew started the trials by testing the performance of the 2 bow thrusters. After profitable operation of each thrusters, the 2 stern thrusters have been slowly loaded as much as about 75% of rated energy every. As {the electrical} load elevated on the diesel turbines, the crew examined the automated energy administration system by organising chosen engines to robotically begin, cease, and share {the electrical} load. The chief engineer acknowledged that the engines have been loaded to about 60% of their rated output all through the trials.
LARGE BANG
At 1435, with the 2 stern thrusters about 75% load, and the no. 3 major engine about 30% load, the engineering crew within the engine management room (ECR) heard a “large bang” and noticed smoke within the engine room by the ECR window. An engineer within the engine room noticed flames close to the no. 3 major engine and acknowledged they “looked to engulf most of the engine.” Crewmembers on the bridge witnessed “heavy smoke from the stack area.” According to the crew, up till this level, there had been no irregular alarms noticed on the engine monitoring system. The no. 3 major engine had been operational for about 4 hours in complete for the reason that January-February overhaul.
The crew extinguished the hearth utilizing the vessel’s carbon dioxide fastened fire-extinguishing system and the complete NTSB report provides extra particulars of the next occasions and the extent of injury suffered by the vessel — which included that the no. 3 major engine was broken past restore.
UNDERSIZED BEARINGS
In its abstract of the report the NTSB says that investigators discovered that the no. 3 major engine’s major bearing journals had been machined right down to a smaller diameter, and undersized bearings have been put in sooner or later previous to the 2022 upkeep.
During the 2022 upkeep, says the NTSB, service technicians didn’t determine the bearing’s half quantity on the service report and changed it with a standard-sized one. The bearing’s incorrect dimension allowed lube oil to leak from the bigger clearances of the bearing. The decreased lube oil provide strain resulted in a fast temperature enhance of the connecting rod bearings and a number of engine elements breaking free whereas the engine was working.
The NTSB decided the possible reason behind the mechanical failure of the no. 3 major engine and ensuing hearth aboard the Ocean Guardian was the alternative of a crankshaft major bearing with an incorrectly sized bearing throughout an engine overhaul as a result of engine service technicians not figuring out the eliminated bearing’s half quantity, which resulted within the lack of lube oil strain in adjoining connecting rod bearings.
“When maintenance is performed, correct replacement of machinery components is critical to ensuring safe and reliable vessel operation,” the report stated. “Vessel crews and equipment manufacturer technicians should carefully identify and document part numbers of all components removed from shipboard equipment. Tracking systems are an effective form of record-keeping that can be used to ensure proper replacement part selection for reinstallation.”
Following the engine failure and hearth, the native Caterpillar service firm switched to a brand new service monitoring system that enables technicians to add footage and experiences on their cell telephones to enhance documentation and knowledge sharing between technicians.
Download the complete report HERE
