MARBLEHEAD – Disabled sailor Maureen McKinnon-Tucker of Marblehead and her racing partner, Nick Scandone of California, have won a gold medal for the United States at the Paralympic Games in China.The pair came in first in the SKUD class sailboat – an 18-foot skiff. Scandone, who suffers from Lou Gehrig’s disease, was at the helm. McKinnon-Tucker, 42, partially paralyzed after a fall from a seawall at age 30, handled the deck work.Last Friday, on the third day of racing, the sailors were leading the fleet in Qingdao Bay, about 450 miles from Beijing. The Paralympics got under way when the Olympics concluded. Dan Tucker, the competitor’s husband, was watching the race from a nearby spectator boat when he realized the U.S. team couldn’t lose.”They were in the zone, so far ahead of the other boats it was almost ridiculous. I was scribbling and calculating frantically on the spectator boat, when I realized that Nick and Maureen could clinch the gold medal that day,” Tucker wrote in an email.Later on Friday, Tucker followed up with another email that bore no message but contained an important attachment – a photograph of the gold medal.”As the Race Committee moved the starting line, I reached the conclusion that the U.S. SKUD team only had to place third or better, and the gold medal was theirs,” Tucker later explained. “The Australian and Canadian boats would be mathematically unable to reach their low point score.”When the wind slacked, the Race Committee postponed the competition until Saturday, when there would be time enough for only two, not three races, due to the starting time. As a result, the U.S. team captured the gold medal at that very moment, leaving the other SKUD-class boats to race Saturday in a quest for silver and bronze medals.”I pumped my fists in the air and shouted, they did it,” said Tucker, who described how he swept his 8-year-old daughter, Dana, off her feet, spun her around, and told her that her mother just won the gold medal. He then began to cry.McKinnon-Tucker and Scandone first heard the news when Brian Todd, the Canadian coach, drove by in his inflatable boat and congratulated them, although the results weren’t official until posted by the Race Committee a few hours later.Once the media learned that the U.S. boat had won the gold, the boat basin erupted into what Tucker described as “absolute bedlam” as photographers, reporters and television news crews scurried to cover the winners. “Not to mention the entire U.S. team and seemingly every sailor, official and volunteer hugging, crying and taking pictures,” said Tucker.McKinnon-Tucker, her husband and daughter are slated to return to Marblehead late Thursday, where they’ll rejoin their 2-year-old son, Trent, who has been staying with close relatives and undergoing treatment for a brain tumor.A parade in Marblehead has been scheduled in the local sailor’s honor on Saturday, starting at 1 p.m. from Old Town Hall, proceeding along State Street to Front Street, and ending at Fort Sewall.Julie Hahnke of Marblehead, the event organizer, said a ceremony and public reception at the fort park overlooking the harbor will follow the parade. Katie Kelly, Olympic Director at U.S. Sailing, is among the dignitaries expected to attend.”Maureen is the first woman to win gold in a Paralympics event worldwide, and she and Nick together are the first U.S. team to ever win a gold medal in the Paralympics,” said Hahnke. “This is very big.”