The National Transportation Safety Board (NTSB) has posted the report of its investigation into the grounding of the towing vessel Justice in the Hog Island Channel near the southwest end of the Cape Cod Canal on March 21, 2013.

Boston Towing and Transportation's towing vessel Justice was heading to Buzzards Bay, Mass., with five crewmembers when it grounded on a hard, rocky bottom southwest of Cape Cod Canal, just outside Hog Island Channel. The impact, at 12:01 a.m. eastern daylight time, sheared the starboard stern drive from the vessel and resulted in the discharge of 232 gals. of gear oil. The vessel docked 15 minutes later without further incident using its remaining port stern drive. No one was injured.

The NTSB determined that the probable cause of the grounding was the mate's ineffective use of the vessel's autopilot to maintain a course within the navigable channel and his delay in taking manual control as the vessel approached charted hazards