HE, if get inside 1/2 a mile of one that's 1/2 mile long, unless boat turns NINETY degrees. have it be towing a ski-doo, wearing your scuba. Get that close, detonator on nose of boat, cut loose the ski-doo, dive overboard. What they gonna do about it, hmm? Have a cutter on each side of each tanker, the last 50 miles? ANY impact means that the tanker either explodes or is set-afire. what you think THAT will mean to the price of gas and diesel, hmm? Stay below water until impact tells you if at risk on the surface, then take off. Not that hard to blow the pipelines between off-loading point and shore, either.