A ferry crewman unintentionally punched a hole in the hull of the M/V Walla Walla as the vessel was being cleaned on Saturday, March 15 at the Washington State Ferries’ Eagle Harbor Maintenance Facility on Bainbridge Island, state officials reported Monday.

The punctured hull means the Walla Walla won’t return to service this week as planned, and the ferry won’t be put back into service until vessel engineers can make permanent repairs.

The ferry Walla Walla, which has a capacity of 188 cars, was at the Bainbridge yard for annual maintenance at the time of the incident.

The work included cleaning out the bilges with soap and pressurized water, and was being done by the Walla Walla crew. Eagle Harbor Maintenance Facility workers were not involved in the incident that damaged the vessel.

Crews from the ferry drilled holes into the bilge deck to drain dirty water and paint chips resulting from the cleaning, officials said.

Ferry workers successfully drilled one 1.75-inch drain hole, but the second drain hole went through the hull and left seawater leaking into the vessel.

Crews used a temporary clamp to plug the leak from inside the vessel. Divers then repaired the external side of the vessel with a durable pressurized patch.

WSF will develop a full repair plan this week.

An investigation into the incident has been launched, officials said.