A boozed-up, off-duty NYPD cop was charged with vehicular manslaughter for fatally ramming into a St. George Ferry Terminal dock worker Friday morning, police said.

William Hemphill, 51, was at Simonson Avenue and Richmond Terrace at around 6:20 a.m. getting a cup of coffee moments before he was fatally struck, according to sources.

Officer Joseph McClean, 29, who joined the force in 2005, was driving a 2010 Ford Escape when he propelled the victim into the air and onto the windshield, the sources added.

McClean fled the scene but returned 30 minutes later, where he blew a .07 on a Breathalyzer before being taken into custody, the sources said.

Cops asked him if he had been drinking, but McClean said, “I’m not talking about that without my [union] rep,” a law-enforcement source said.

Hemphill was pronounced dead at Richmond University Medical Center.

The cop was also charged with DWI, according to the District Attorney’s office. Bail was set at $50,000.