They helped to storm the beaches of Normandy on D-Day, but they won't be cruising the streets of Manhattan.That is if an environmental group gets its way. The organization Transportation Alternatives is going to court to keep duck boats out of the Big Apple. The ducks are amphibious trucks developed for the Army during World War Two.Port Imperial Duck Charterers wants to provide sightseeing trips in the water and through the streets of New York. The environmentalists charge the ducks would increase noise and pollution and cause safety problems.Duck boats already carry tourists in a number of waterfront cities including Baltimore, Philadelphia, Boston and Seattle.