City police were patrolling the river near Penn's Landing around 7 p.m. when a member of a sailing club flagged them down about a stolen vessel, the department said.
A Philadelphia police boat cruised south and spotted the sailboat near the Walt Whitman Bridge, where a Coast Guard unit was already in pursuit, authorities said.
The thief stopped the boat, identified himself as a federal agent, and told the Coast Guard team he was armed, according to police.
He was arrested and identified as 31-year-old Roger Pojar. He has been charged with theft and illegal gun possession among other counts, PPD said. Investigators believe the gun he had was also stolen.
Court records show Pojar was arraigned early on Thursday, Aug. 17, where his bail was set at 10 percent of $150,000. He is scheduled to appear in a Philadelphia court on Aug. 31.
Click here to follow Daily Voice York and receive free news updates.