BC Ferries has launched a full investigation after one of its vessels crashed into a dock on Mayne Island, in B.C.'s Gulf Island chain northeast of Victoria, injuring four passengers and one crew member.

An air ambulance was dispatched to the Village Bay terminal shortly before 8 a.m. after the Queen of Nanaimo took a hard landing and slammed into the berth.

The impact of the collision sent passengers and food supplies tumbling to the floor in the ship's cafeteria and caused motorcycles to fall over in the vehicle deck.

Coast Guard boats, aided by the Mayne Island Fire Department, rushed to the scene to assist. Local RCMP cordoned off the scene with tape and counted and interviewed passengers as they disembarked.

In Pictures: B.C. ferry crash

Of the 201 people on board the ship, five suffered non-life threatening injuries.

An elderly passenger with California licence plates on her vehicle struck her head on a pole after being thrown from her seat while having breakfast at a table in the cafeteria. She was attended to by her husband, a doctor, before being airlifted to Vancouver General Hospital with a concussion.

Another passenger was taken to the Mayne Island medical clinic for treatment. A female ferry worker was injured while she was standing on the ship deck when the vessel hit the dock.

BC Ferries Chief Operating Officer Mike Corrigan said the cause of the crash is still under investigation but the ferry had dropped its anchor before the accident, indicating a possible loss of power.

"Essentially the ship was coming in with more speed than it otherwise should have," Corrigan said. "There's a number of potential reasons for that. We really don't know what they are right now."

A ferry employee told CTV News there was a problem with the ship's reverse thrust, saying that the vessel lost pitch on its propeller when it was braking and the captain had no choice but to drop one of its anchors.

Both the berth of the vessel and the terminal were damaged on impact.

"The terminal sustained damage to the wingwalls, which are part of the berthing structure, as well as to the ramp apron," BC Ferries spokeswoman Deborah Marshall said.

Marshall said the company would use the bridge deck's voyage recorder to gain more information about the minutes leading up to the incident.

Service on the Queen of Nanaimo, which runs between Tsawwassen and the Gulf Islands, is suspended indefinitely. There is no word on how much it will cost to repair the ship. Service between Tsawwassen and the Gulf Islands is being re-routed via Swartz Bay.

The Village Bay terminal remains open because other ferries are able to dock at another location.

This isn't the first hard landing in recent years for BC Ferries.

In June 2005, the Queen of Oak Bay slammed into a nearby dock in West Vancouver after losing power while coming into Horseshoe Bay.

No one was injured but the collision damaged multiple boats moored in the bay.

BC Ferries conducts more than 182,000 sailings every year in British Columbia.

"If we have one significant event like this a year it's pretty rare," Mike Corrigan said. "So something happened and we really need to find out why."