BOSTON — Federal investigators have determined that the likely cause of the sinking of a fishing boat off the coast of Nantucket in 2017 that claimed the lives of two crewmembers was flooding in one of the vessel's clam tanks.

The National Transportation Safety Board in its Feb. 6 report said although flooding in the Misty Blue's port clam tank was the ``probable cause'' of the sinking, how the water got in remains undetermined.

The flooding caused the vessel to list, allowing seawater to be trapped on deck, decreasing stability.

The 69-foot, New Bedford-registered Misty Blue was harvesting clams nine miles southeast of Nantucket in December 2017 when it sank. Two crewmembers were rescued by another vessel. Two others were trapped on board and died. They were previously identified as Jonathan Saraiva and Michael Roberts.

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