RedactedNarrative: Vessel 1 was travelling east in an un-named pipeline canal which intersected with the Houma Navigation Channel.  The vessel struck a submerged piling on its’ starboard side causing the vessel to list sharply to its’ port side.  The list was so dramatic that it caused the port gunwhale to submerge swamping the vessel which then sunk.  None of the four subjects on board were injured, and impairment is not suspected.  All subjects were able to get to the shore where they were rescued by agents.