A hospital ship struck the dock of the USS Arizona Memorial in May after the pilot and ship’s captain lost track of where the ship was going as it was leaving Pearl Harbor, an investigation into the incident released Wednesday said.

The harbor pilot on board the USNS Mercy had poor control over tugboats guiding the ship, said a report by the U.S. Military Sealift Command. This resulted in the ship unexpectedly heading toward the Arizona. It also led the pilot and the ship’s captain to lose track of where the ship was going for three minutes, leading the ship to hit the dock, the report said.

Waves generated by the propeller in the back of Mercy pushed the floating dock about 12 feet toward the memorial, the report said. This damaged the dock. The Mercy had 6 inch-long scrape marks, but no structural damage.

The Navy and the National Park Service closed the national landmark for over a week after the May 27 incident while crews repaired the dock.

The report said the chief mate’s lack of experience contributed to the incident, as did the navigator’s lack of experience and effectiveness.

The report made clear having the pilot on board to guide the ship didn’t absolve the captain, Capt. Thomas Giudice, of responsibility.

“The master’s responsibility for his ship is absolute. The master is responsible for the safe navigation of the ship,” the report said. Pilots are technical advisers or assistants, it said. The pilots at Pearl Harbor work for the Navy and are assigned to Joint Base Pearl Harbor-Hickam.

The report, which was dated July 10, recommended that leadership take “administrative or correction action” toward the captain, chief mate and navigator “as it deems appropriate.” Rear Adm. Thomas K. Shannon, the commander of the Military Sealift Command, approved the report on Sept. 3.

Administrative actions were taken regarding the captain, command spokesman Nathan Potter said in an email. Details about the administrative actions were protected under the Privacy Act, he said.

The memorial honors the 1,177 sailors and Marines on the Arizona who died when Japanese planes bombed Pearl Harbor in 1941. Most of those killed are still entombed on the battleship, which lies in the harbor.

Visitors ride boats operated by the Navy to visit the memorial, which sits atop the sunken ship.