The first two women to testify at the trial of former high school teacher Tom Ellison have told the court their first sexual experiences were with him aboard his boat anchored in Vancouver's False Creek.

The two say they first came into contact with Ellison while enrolled in the Quest outdoor program at the city's Prince of Wales Secondary School in the early 1980s.

Tom Ellison is facing 16 sex-related charges in Vancouver provincial court.
(CBC)

Both testified that he had taken special interest in them and that that interest eventually led to invitations to his boat.

Ellison, 63, who taught at the school in the 1970s and 1980s, is facing 16 sex-related charges in Vancouver provincial court. They include 12 charges of gross indecency, three of indecent assault and one of sexual assault.

The Crown opened its case on Tuesday by telling the court the testimony of 12 women would demonstrate a pattern.

Eleven of Ellison's alleged victims were enrolled in the Quest program. The Crown said many of them had a crush on Ellison.

Prosecutor Ralph Keefer said Ellison abused his power to "manipulate and exploit" the students, who at the time ranged in age from 15 to 18.

Keefer said that abuse included kissing, fondling and sex — and the Crown alleges that in some cases, it wasn't consensual.

Former student Laura Anderson, who asked the court to lift the ban on publication of her name, said that at 17 she went to Ellison's boat with him. She said she initiated a kiss and he fondled her.

She testified he told her to tell no one what had happened.

Anderson spoke to reporters outside court about her memory of events that happened more than 23 years ago.

"I just tried to really be solid about not answering anything that I didn't feel really clear about. And that was my focus, being as truthful as I could be," she said.

The defence hasn't begun its case yet. However, Ellison's lawyer, Bill Smart, has indicated he will argue that the charges are too vague and that Ellison's actions were not illegal at the time they occurred.

Ellison, who taught the Quest program from 1972 to 1987, now runs adventure tours along the B.C. coast.