VANCOUVER -- The only two people who know what really happened on the bridge of the doomed Queen of the North passenger ferry in the minutes before it struck a remote island off British Columbia are liars who colluded to fabricate a story to cover up what really happened, a prosecutor told a jury Friday.

Navigating officer Karl Lilgert, now on trial for criminal negligence causing death, and his former lover, Karen Briker, each told the jury Lilgert was attempting to navigate the ferry through rough weather when, out of nowhere, an island appeared and pierced through the ship's hull. Lilgert insisted he was off course because he was attempting to avoid two small boats.

But those stories were nothing more than lies, the Crown prosecutor told the jury, dreamed up to hide the reality that Lilgert wasn't paying attention as the ferry sailed into the night on a deadly collision course.

"The explanation offered by the accused is completely unbelievable," said Crown counsel Robert Wright, as he delivered his final submissions to a B.C. Supreme Court jury.

"It has been fabricated and concocted with Ms. Briker to disguise the fact that he wasn't navigating the Queen of the North at the crucial time."

Lilgert has been on trial since January for the deaths of passengers Gerald Foisy and Shirley Rosette, who haven't been seen since the ferry collided with an island and sank in the early morning of March 22, 2006.

Lilgert was alone on the bridge with Briker, a quartermaster, in the half-hour leading to the collision. Their six-month sexual affair had ended just weeks earlier, after each of their spouses caught wind of the relationship, but both insisted there were no hard feelings and the breakup played no part in what happened.

Lilgert testified in his own defence, telling the jury he was keeping a close eye on his radar while attempting to navigate the ship as it entered a large body of water known as Wright Sound.

He said he delayed a scheduled turn in order to stay clear of a tug boat he believed might be in the area, and then ordered at least two course corrections, in part to avoid a second boat and also because the wind was pushing the ferry sideways through the water.

But Wright pointed the jury to GPS information retrieved from the ship's navigation system after the sinking. It depicts a straight line from when the Queen of the North entered Wright Sound, where the ferry should have made a routine left turn, until it collided with the island.

In fact, Wright said the ship ended up hitting the island in precisely the same point it would have if there had been no changes in course.

"Either this is a remarkable coincidence, or, as we say is the case, there never was an alteration," said Wright.

Wright also said Lilgert knew the tug boat was no where near the Queen of the North, and the second boat, which Wright described as "the fake boat," never existed. He also reminded the jury that many of the survivors who testified at the trial said the weather was relatively calm before and after the collision.

A day earlier, Lilgert's lawyer, Glen Orris, said Lilgert made honest mistakes and shouldn't be turned into a criminal because of them. He also launched a scathing attack on BC Ferries, the former Crown corporation that operates the province's ferry system, accusing the company of cutting corners on equipment and staffing to save money.

Wright said Lilgert's lawyer was correct in asserting that honest mistakes aren't crimes, but he said that's not the case here.

"You know what happens when mistakes are dishonest? They need to be examined," said Wright.

"We are dealing with dishonesty here with the accused's testimony and with what happened that night. It's not an honest mistake."

During Lilgert's cross-examination, a Crown lawyer suggested Lilgert was distracted because he was either having sex with Briker or arguing with her, which he denied.

On Friday, the affair between Lilgert and Briker didn't factor heavily into Wright's final submissions, though he repeatedly told the jury Lilgert was distracted.

Lilgert's lawyer also suggested there was no concrete evidence Foisy and Rosette died in the sinking, noting several witnesses said they may have spotted them in Hartley Bay, the small First Nations community where many of the survivors were taken.

Wright said no one recalled seeing the couple in life boats or life rafts after the ferry was evacuated, and he suggested survivors who thought they may have seen them in Hartley Bay were simply mistaken.

If Foisy and Rosette had made it off the ferry, Wright told the jury, someone would have heard from them.

"We're not talking about some wealthy billionaires disappearing and they're in Mexico hanging out with Elvis," said Wright.

"That's what you'd have to believe to believe these two unfortunate people are not dead. It's incomprehensible. They disappeared from loving family. They left orphaned children."

The final stage of the trial begins Monday, when the judge hearing the case is scheduled to deliver her instructions to the jury, which will then retire to deliberate its verdict.

Lilgert was charged with two counts of criminal negligence causing death. It will also be open to the jury to consider the lesser charge of dangerous operation of a vessel.