A 47-year-old Greenwood man confessed to setting two yacht-style vessels adrift in the Duluth harbor last week, according to a St. Louis County District Court criminal complaint filed Thursday.

A Duluth officer remembered Gregory M. Sullwold from a previous incident in Canal Park, where he was allegedly threatening to blow up the Club Saratoga nightclub. Police then arrested Sullwold on an unrelated warrant out of Hennepin County. He was “particularly interested” in “the boats floating in the harbor. He also seemed to boast of his knowledge in boats,” the complaint said.

Sullwold was interviewed and confessed, the complaint said. He was charged with felony theft-indifferent to owner rights. He faces up to 10 years in prison and a $20,000 fine.

Sullwold is accused of setting free the Vista Star and its smaller fleetmate, the Vista Queen, shortly before sunrise in the Duluth harbor on Sept. 21. Both vessels were recovered undamaged, but the abandoned Queen was in the path of a 730-foot Canadian shipping vessel that was unable to slow down or divert course because of its size. A fast-acting crew member was able to board the Queen and guide it into the slip with a U.S. Coast Guard escort.

Police obtained a “plethora of video” from the harbor. One video shows a man unmooring the Queen and leading it out of the slip and into the harbor. That act required advanced nautical knowledge, police said.

According to surveillance, the 100-ton, 85-foot Vista Star, and the 60-ton, 65-foot Vista Queen were unmoored about 2:47 a.m.

Vista Fleet owner Justin Steinbach was alerted to the trouble just after 6 a.m. with a phone call. He and his crew rushed to the harbor to rescue the boats he uses for harbor cruises and events. The Star can accommodate 225 passengers. The Queen can carry 75.

In the past five weeks, Sullwold has been charged in a handful of incidents from domestic assault and violating a protective order to terroristic threats.