BELMAR - From home plate at Memorial Field you can see the American flag fluttering in the distance, beyond the center field fence and across Main Street. Beneath the flag, at the corner of 13th Avenue, is the borough’s post office. It’s a long, long way from the batter’s box. You wonder: Did a man really hit a baseball that far? “If you walk it off, it has to be one of the longest home runs hit anywhere, anytime,” said Spencer Heulitt, president of the Belmar Historical Society. The hitter was Josh Gibson, a legendary slugger of the 1930s and 1940s known as “the Black Babe Ruth.” With Major League Baseball played by whites only, Gibson starred in the Negro leagues and on barnstorming tours. His Pittsburgh Crawfords team paid multiple visits to Memorial Field, which was part-time home to the rival New York Cubans and full-time home to the semipro Belmar Braves.