PLYMOUTH – Dignitaries, seafarers and scientists were gathering in Plymouth, England, on Wednesday to mark the 400th anniversary of the departure of the Mayflower, the ship that carried a group of Puritan settlers to a new life in America.The journey would launch a new chapter of expansion and empire for Europe, and bring disaster for the Native peoples who had lived in the Americas for millennia.Adrian Vinken, chairman of Britain’s Mayflower 400 commemorations, called it “arguably the most influential sea voyage in global maritime history.”Four centuries to the day since the ship sailed out of Plymouth harbor, dignitaries from the United States, the U.K.