The Captain Richard G. Spear, shown at the ferry terminal in Rockland, returned to service in mid-November. Stephen Betts/Courier-Gazette

ROCKLAND — The Aug. 16 grounding of the Captain Richard G. Spear ferry off Vinalhaven was caused by human error.

That is the finding of independent investigations made by both the Maine Department of Transportation and the U.S. Coast Guard, according to Maine DOT Director of Communications Paul Merrill.

“Based on the results of the investigation, MaineDOT concluded that human error was the cause of the incident and we have taken appropriate action,” Merrill said.

He did not specify what that action was and said no final written disciplinary action has been taken.

The Maine Department of Transportation said in a statement after the grounding that the employee who was captaining the Spear during the incident was a longtime MSFS team member who has experience making the run between Rockland and Vinalhaven.

The Captain Richard G. Spear returned to service in mid-November. The cost of the repairs from the grounding was approximately $150,000.

The Ferry Service’s newest ferry suffered significant damage when it struck a ledge off Vinalhaven on Aug. 16. The starboard rudder of the Captain Richard G. Spear was damaged and the port rudder was knocked off from the impact with the ledge. There was also damage to at least one propeller.

The Spear was pulling away from Vinalhaven shortly after 10:30 a.m. Aug. 16 when it hit the ledge. There were 65 passengers and five crew members aboard at the time of the grounding. There were no injuries. The incident occurred about 90 minutes before high tide.

The Spear was then taken to Rockland Marine Corp. shipyard repair facility on Mechanic Street in Rockland where the repair work was done.