Unfortunately
Practice dictates for you NOT to hail any business-related large vessel unless you have specific, information for them. They are focused on moving their craft safely through crowded waters... just get out of their way: quickly, deliberately and without fanfare. Protocol would be for you to get on Channel 13 (the bridge to bridge) VHF Channel and say, "Eastbound large tanker approaching Bouy 17, this is sailboat Alure off your port bow."Be clear and sure exactly which boat you are trying to contact. Then switch to a working channel to exchange information, just as you would for a marina or fellow recreational boater.You might try Channel 16 as well, with the same 'greeting', should that not work.My personal experience with freighters and those big gray boats around Norfolk, is that, they don't talk to anybody on the radio, unless the caller is another one of their kind: not your kind. The way they communicate is ONE WAY: long, loud warning horns to get you out of the way!Take care and stay far, far away from the shipping lanes. Joe