VANCOUVER -- The crew at the helm of an ill-fated B.C. ferry missed at least 12 minutes worth of crucial checks, something an expert mariner told a criminal negligence causing death trial was a "catastrophic dereliction" of duty.

Andrew Flotre has 23 years of experience piloting large ships up and down the province's coast and testified Thursday at the jury trial of former BC Ferries navigation officer Karl Lilgert.

Based on the evidence Crown counsel presented, Flotre said the officer in control of the Queen of the North failed to perform some of the most basic safety measures and checks.

"The fact that no action was taken substantially to get back onto its proper course -- in my professional opinion -- is an extreme, catastrophic dereliction of your duty," Flotre said.

Lilgert was charged after the Queen of the North ran aground on Gil Island and sank in March 2006 but has pleaded not guilty to two counts of criminal negligence causing death.

Ninety-nine passengers and crew were evacuated from the ship as it went down, leaving two passengers -- Gerald Foisy and Shirley Rosette -- missing and presumed drowned.

Flotre told the court that any officer who assumes control of the ship is responsible for navigation and safety, despite his or her experience.

Lilgert failed his duty as officer when he missed a scheduled course alteration, Crown counsel alleges.

The trial already heard that Lilgert was alone on the bridge with his former lover Karen Briker on the night of the sinking. It was the pair's first night working together since they had ended an affair weeks earlier.

Briker told the jury earlier that she and Lilgert had been talking about a recent house purchase with her common-law spouse just before the ferry struck land.

The defence has argued poor weather, faulty equipment and inadequate training were to blame.

His lawyers have also suggested Lilgert was off course because he was attempting to avoid crashing into a fishing boat -- all points Flotre refuted in court.

While errors can happen at night or in inclement weather when officers lose visibility, Flotre said the officer in charge should have reduced the ship's speed and conducted checks every two minutes to ensure the vessel stayed its correct route.

"I don't see any ... indication that he had taken any action," Flotre told the court.

The ferry was travelling at a speed of 17 to 18 knots for at least 12 minutes after it went off its planned course.

"In my opinion, 12 minutes is an extraordinary amount of time hurtling through the night ... without making sure and taking action," Flotre said.

Strong winds and heavy rains were unlikely to have put the ship off course, he said, adding the ferry should have slowed down if officers faced poor conditions.

Furthermore, Flotre said he couldn't see abnormalities in winds or currents during the time of the incident, around midnight on March 22, 2006.

Radar would have made it clear the ship was steering towards Gil Island at least 12 minutes before the vessel reached the point of no return, Flotre said, yet he could see no evidence that Lilgert was engaged in what he called meaningful navigation.

"He failed to monitor and use the information given to him," he said.

"If he was experiencing heavy weather, it would have indicated that he should have been taking actions. If he had restricted visibility, he would have been required by the regulations ... to reduce the speed of the ship."

Flotre also disputed the defence's claim that Lilgert had insufficient training -- he said there was sufficient evidence on the officer's record to indicate Lilgert knew how to operate radar controls and adjust the direction of the ferry.

The jury heard the ship had the necessary equipment Lilgert needed to do his job -- various radar systems, global positioning systems that rely on satellite, as well as magnetic and "true North" compasses.

All steering systems were operating correctly, the court heard, and Lilgert had no pre-existing medical conditions that would have impaired his ability to navigate the ship.

In any case, a senior officer was 30 seconds away if Lilgert had needed assistance with the ferry's controls, Flotre said, yet he made no calls to the second officer.

The mariner said damage to the ship's hull indicated no attempt had been made to change the direction of the rudder. Had there been changes, the damage would have occurred along the side of the ship.