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NTSB: A fatigue crack caused the grounding of Alaska

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Written by

Nick Blenkey

Barge grounded following a fatigue crack in a component of the mooring system. [Image; NTSB/Alaska Marine Surveyors, Inc.​]

A fatigue crack eventually led a fishing barge to break loose from its mooring buoy and run aground during a storm near Ekuk, Alaska, the National Transportation Safety Board (NTSB) said in a marine survey report released on Tuesday.

The tender fishing barge, the SM-3 broke away from the buoy it was anchored to and began to drift on August 30, 2022. The crew of six deployed two backup anchors, but the barge continued to drift and ran aground on the beach . No injuries were reported. There was a three mile debris field on the beach. The vessel suffered damage estimated at $4.5 million.

As always, the summary summary published by the NTSB does not tell the full story that emerges from the full report. For example, if you don’t know exactly what a fishing barge is, this one started life in 1966 as a deck barge and until 2017 when it was purchased by Northline Seafoods, she was primarily used for docking and logging operations at Dall Island. , Alaska.

In 2018 the barge was towed to Sitka, Alaska, and in January 2019 the hull frame and plating was extensively renewed, and the vessel was converted to a four-deck fishing barge.

The full report also gives an overview of the work on board the ship.

“During the season, the SM-3 provided tendering services (ice, fuel and water) to the fishing boats that operated in the area along the SM-3 to sell their catch, as well as “processed” fish. Up to 40 crew members, headed by the Manager (PIC), who was also the general manager of the company, worked on board the SM-3 in 12-16 hour shifts to freeze whole fish, canned fish and transfer pallets of frozen salmon up a ramp to the storage barge [the Riverways-11], by forklift. When the holding barge had had enough frozen fish to fill six containers, a contract vessel with containers on deck moored alongside SM-3, and the SM-3Deck cranes unloaded cargo onto the contract vessel for transport to Dillingham, Alaska, 21 miles north of where the vessel was anchored.

“About 2.5 months into the season, on August 19, the SM-3 terminated major fishing operations with 17 crew on board,” the NTSB report said. “The crew took the next few days to freeze and move the fish, concluding the season. From 23 to 24 August, all but eight of the crew (six for barge handling and two for the Sea Mount) had been paid off and sent home. The rest of the crew, which included the captain, the senior deckhand (who was also the IT manager), the operations manager, the fishmonger’s manager and two deckhands on the SM-3, as well as a captain and a deckhand on the Riverways-11, began preparing the barges for winter layup. The PIC and IT manager discussed their need for a 3 day window of good weather to move the two barges to their separate wintering locations.

A storm blew through the area on August 30 with winds estimated at 50 to 60 mph. The storm brought in forces that exceeded the capacity of the mooring buoy, the weakest link in the barge’s ground tackle system. Once freed from the buoy, the barge drifts and ends up landing on a beach. The next morning, the crew evacuated the ship and were picked up by locals.

FATIGUE CRACK

The NTSB determined that the probable cause of the grounding was a fatigue crack in one of the mooring buoy’s padeye welds, which caused the padeye to separate from the buoy’s spherical steel plating, causing the barge to break off its buoy and anchors and drift ashore during a storm.

“In addition to installing mooring chains of sufficient length to provide adequate span for anchorages, sailors should consider the strength of each component of a ground tackle system and should refer to marine standards for design,” the report said. “Bending loads can be significantly higher than straight line tensile. The working load limit of each component must be equal to or greater than the calculated maximum load of the ground tackle system to avoid system weak points.

The NTSB determined that the probable cause of the grounding was a fatigue crack in one of the mooring buoy’s padeye welds, which caused the padeye to separate from the buoy’s spherical steel plating, causing the barge to break off its buoy and anchors and drift ashore during a storm.

Read the report HERE.

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