water fronlt could be hurt. >> 2015, boston harbor. a 1,000-foot tanker carrying lng sails at five knots into boston harbor, nearby downtown and logan airport, all densely populated. as is normal when an lng tanker approaches the harbor, no other traffic is allowed on the water. security is tight. >> helicopters are overhead. the roads are closed on the side. bridges are closed. there is a moving security cordon on either side of the vessel. >> but the massive security presence is looking the wrong way.