AUGUSTA — Admitting he was high on crack cocaine at the time, a homeless man pleaded guilty Tuesday to charges that he kidnapped a 52-year-old woman from a parking lot in December and robbed her.

When the woman tried to honk her horn for help after the kidnapper forced her into her car at knifepoint, he told her if she didn’t stop doing that, “I’ll gut you like a fish.”

Shawn A. Doray, 33, a transient most recently living in a basement in Augusta, then drove the woman’s car to an ATM to try to force her to withdraw money.

He became enraged and stabbed the knife into the roof of the car when she told him it wouldn’t work because she was from out of the area.

Finally, he took $180 from her and got out of the car on Mount Vernon Avenue, telling her not to call police. She drove herself to a nearby store to report the crime.

Assistant District Attorney James Mitchell Jr. described the scene from the evening of Dec. 20, 2011, to Justice Donald Marden on Tuesday in Kennebec County Superior Court shortly after Doray pleaded guilty to robbing and kidnapping the woman as well as charges of criminal threatening and criminal mischief.

Doray was sentenced to 15 years in prison, with all but eight years suspended, and three years of probation.

He also was ordered to pay $1,180 restitution, which included money to repair the interior of the car roof.

Doray had accosted the stranger in the parking lot of Walmart on Civic Center Drive, about an hour after smoking crack cocaine, he said.

“It’s a terrible affliction,” Marden said, referring to the role of drugs in the offense.

Doray told the judge he was concerned about his young son, whom he believed was living in an abusive atmosphere. He said that was resolved after the state Department of Health & Human Services stepped in.

Police received a number of tips about the suspect, and when he was arrested two weeks later, he made a full confession.

“I let them know every detail,” Doray told the judge. “It was the first time I’d done anything like this.”

“Mr. Doray is accepting this plea agreement because there were circumstances that led him to this criminal behavior,” said Doray’s attorney, Stephen Bourget. “He was very remorseful, and very forthcoming with authorities.”

Doray, who said he has worked as a marine worm-digger, also was ordered to pay up to $2,000 for any future counseling for the victim, who was terrified by the encounter.

Mitchell said the victim knew about the hearing and sentence, but did not want to speak in court Tuesday.