The former lover and fellow crew member of the officer in charge of navigating the Queen of the North passenger ferry the night it sank, testified at the trial underway in B.C. Supreme Court in Vancouver on Monday.

Karen Briker told the jury Fourth Officer Karl Lilgert ordered her to switch off autopilot shortly before the ship struck an island seven years ago, but she says she didn't know how to do that.

Briker also said she later overheard Lilgert tell a senior officer that he had been attempting to avoid a fishing vessel and that poor weather had interfered with the ferry's radar system.

Lilgert, who is charged with criminal negligence causing death, was on the bridge of the Queen of the North passenger ferry with Briker when the ship struck an island and sank in March 2006.

The two had been involved in an intimate affair for several months, but Briker ended the relationship weeks earlier. At the time of the collision, they were working alone together for the first time since the affair ended, the trial has heard.

Karen Briker told the jury Karl Lilgert ordered her to switch off autopilot shortly before the ship struck an island, but she says she didn't know how to do that. (CBC)

Briker was in the role of quartermaster at the time, meaning her job when the ferry was on autopilot was to look out for any hazards outside.

She testified Lilgert ordered her to dial a course change into the autopilot system. The change seemed unusual to her, she said, but Lilgert repeated the order.

Soon after, Briker said she saw trees that were illuminated by the ferry's lights.

"I then remember hearing him say something like, 'Oh my God,' or, 'Oh no,"' Briker told the jury.

"He then ordered me to turn off the autopilot and I told him that I didn't know how."

The ship had recently returned from scheduled upgrades, including changes to its autopilot system. Briker was a casual employee, and she said she hadn't worked on the bridge of that particular ship for almost a year.

Briker said Lilgert switched the autopilot system off himself and turned the wheel, though she said she didn't feel the ship move. She then went to get the ship's captain.

Shortly after, Briker said she overheard Lilgert speaking with another officer.

"I heard him say, 'I'm sorry, I'm sorry, I was trying to go around a fishing boat. We hit a squall and the radar screen had whited out,"' recalled Briker.

Relationship theory

Lilgert was the officer in charge of navigation when the ferry missed a scheduled course correction shortly after midnight on March 22, 2006, hours after leaving Prince Rupert for Vancouver Island.

Briker had been involved in an affair with Lilgert for months. In the weeks leading up the sinking, Briker told Lilgert she had decided to stay with her common-law spouse. Lilgert also had a spouse, Briker testified.

The Crown highlighted the pair's relationship in its opening statement in January, but prosecutors have yet to say exactly how the affair and subsequent breakup fits into their theory about what happened on the bridge that night.

Briker corrected a Crown lawyer who described their relationship as a romantic one.

"I'd prefer to call it a sexual relationship," she said.

Before the ship left on its final voyage from Prince Rupert, Briker said the pair had tea in a cafeteria. Other colleagues arrived, and she showed them paint swatches she was considering for the walls of a home she had recently purchased.

Hours later, when Briker and Lilgert found themselves alone together on the bridge, Briker said the subject of the house came up again.

"He and I had a brief conversation in regards to the house; he said something to me like that he didn't know that I was buying a house and I replied something like that I had just bought it," she said. "That was about it for conversation."

Briker said Lilgert was calm and did not appear upset when he asked her about the house.

Nighttime rescue

The Crown argues Lilgert was negligent when he missed a scheduled alteration correction as the ferry entered Wright Sound, a large body of water off the North Coast of British Columbia.

That failure sent the ferry sailing toward Gil Island, and the Crown alleges Lilgert did nothing to steer the ship away from the island or even slow it down before the collision.

The defence says inadequate training, unreliable equipment and poor weather were factors in the collision.

Defence lawyers have also blamed staffing policies within BC Ferries, the former Crown corporation that operates the province's ferry service, which they say left Lilgert on the bridge without the help he needed.

The sinking set off a dramatic nighttime rescue, which saw residents from the tiny First Nations community of Hartley Bay head to the scene in their fishing boats.

The evacuation and rescue saved 99 passengers and crew, but two passengers Gerald Foisy and Shirley Rosette were never seen again and presumed drown.

Lilgert has pleaded not guilty to two counts of criminal negligence causing death. His trial is expected to last until late spring or early summer.