The Transportation Safety Board and BC Ferries have launched separate investigations into a ferry that got thrashed around in violent seas earlier this week, an overnight incident that damaged several cars and left passengers shaken.

And has learned that the marine forecast that night for the Hecate Strait -- where the Northern Adventure ended up stranded for hours -- had called for winds to reach 40 to 60 knots and wave heights to reach at least five metres.

BC Ferries protocol says the Northern Adventure should not enter waters with wave heights that exceed 3.6 metres.

Yet, the ferry departed from Prince Rupert at 11 p.m. Sunday bound for Skidegate on the Queen Charlotte Islands.

As the ferry sailed through the Hecate Strait later that night, the waves grew more menacing.

According to Environment Canada, observations from a buoy in the Hecate Strait showed average high waves were 3.1 metres at midnight, 4.4 metres at 2 a.m., 5.4 metres at 3 a.m., and almost seven metres at 5 a.m.

Peak waves probably reached 12 to 14 metres, said Environment Canada meteorologist David Jones.

"The observations match the forecast very well," he said.

BC Ferries response

In an email Wednesday, Deborah Marshall, a BC Ferries spokeswoman, said the captain was aware of the storm warning before departure and knew the waves would increase after midnight. He checked wave readings from a Hecate Strait buoy, which showed waves at two metres, she said.

"Given the storm was to hit after midnight, the captain believed he could be in a position off the east side of Hecate Strait before the storm hit. He expected that after that, they would have been in a fair position to weather the storm for the remainder of the journey. The captain planned to transit to Edye Pass and observe the conditions there first hand before proceeding across Hecate Strait."

Marshall said that at 1 a.m., a buoy just past Edye Pass and at the start of Hecate Strait, showed winds at 20 to 30 knots and two-metre seas.

"The decision to continue the voyage was based on the observed conditions at the time," she wrote.

But, she said, the storm hit sooner than expected and with greater ferocity.

Damage and concerns

As a result of the wallop, some of the 42 crew members got bumps and bruises, four cars were damaged, and chairs and dishes broke, BC Ferries has said.

The ferry's bow thruster -- which helps the ferry dock -- was also temporarily knocked out of commission.

Passengers have said that at about 7 a.m. Monday -- eight hours into their trip and when the ferry should have been at or near its destination -- the captain announced they were turning around. They got back to Prince Rupert at about 1 p.m.

Two passengers later told that they questioned why the captain decided to depart in the first place.

"The captain should never have sailed in the first place. He put everyone's lives in danger," said Katrina Overton, one of the passengers, who lives in Queen Charlotte City.

The passengers also said they were angry that the captain didn't make any announcements sooner.

"(He said) nothing to calm the passengers down," said Tara Sjolund, a Masset resident, who rode out the storm with her family on a mattress on the floor.

Marshall said the captain made two announcements during the trip, though she didn't know when. The chief officer also made an announcement in the "wee hours." Crew members walked around the ship talking to passengers to keep them updated, she said.

Two investigations

Marshsall said BC Ferries has launched an internal investigation.

She declined to identify the captain, citing privacy reasons.

Kevin Hall, a labour relations officer with the BC Ferry and Marine Workers Union, said the union is taking part in the investigation and that part of the investigation will look into ways to mitigate risks in the future.

The Hecate Strait is notorious for rough seas, he said, but "this was more extreme."

The Transportation Safety Board is also investigating.

Raymond Mathew, a senior marine investigator with the TSB, said investigators plan to interview the ship's captain in the coming days to see if protocols were followed.

The decision to launch an inquiry was made because the vessel got caught in bad weather, because there was damage, and because of the media coverage, Mathew said.

"There's a public expectation," he said.