By Anna Spivak

The foghorn tooted and  the  3:30 p.m. ferry  left Whitehall Station bound for the “forgotten borough” of  Staten Island  on Tuesday – with Bill de Blasio along for the ride.

But the liberal public advocate courting votes in his bid for the Democratic nomination for mayor in the city’s most conservative outpost didn’t venture any farther into the borough than the terminal on the Staten Island side, where he shook hands, answered questions and posed for photos with passengers before heading back to Manhattan.

The six-foot-five candidate, hard to miss among the commuters, got a mixed reception.

“He’s a politician, just like them all,” said Lauren, a Staten Island resident who declined to give her last name.

But other commuters were inclined to give the candidate – who sailed with wife Chirlene and daughter Chiara – to give him the benefit of the doubt.

“I like him. I think he offers a good change for the city.,” said Frank DeSantis, who has lived on the island for 27 years.  “I just hope he doesn’t forget about us as a borough.”

“The fact that he is taking public transportation shows an effort to be a man of the people, said Patrick Broderick, another Staten Island resident .

Campaign volunteer Tom Shcherbenko said, “Bill has had friends here since he was a city councilman,” and that riding the ferry would give him “the chance to see as many Staten Islanders as possible.”

The candidate recounted his day’s itinerary: “We are in our fifth borough now,.We started in Brooklyn, in Crown Heights, went up to Astoria then to Co-op City and the Upper West Side, and now we’re in Staten Island.”

Well, in the ferry terminal, anyhow.