It has been an unusual past 100 years for Noman’s Land, that half-forgotten rock off Chilmark and Aquinnah that has occasionally reasserted its presence to Vineyarders with wafting smoke clouds and distant bomb blasts. Shrouded in mystery and explosives, it has seen rumrunners, pirates, hurricanes, and even an accidental internecine gun battle between the Coast Guard and the Navy in 1967.