CROSSING THE STREAM

0615 hours, Sunday Dec 7, 2014, Great Bahama Bank.  We passed between Great Isacca with it's unlit lighthouse and Hens and Chicken two small islands at the north west corner of the Great Bahama Bank.  It was a busy crossing during the night we saw at least 40 AIS markers most all ships heading north or south. One, a Carnival Cruise Liner had to be contacted by radio, who reluctantly  changed course to avoid a collision with us.  We had the right of way and we were maintaining course and speed as required.  In a second close encounter with a large cargo ship where we were burdened and to changed course.   A third near encounter occurred when we passed very close to a 150' super yacht towing a 30' tender a couple of hundred yards or more behind.  Although the tender was lit  the super yacht did not carry the two mast head lights required which provide warning of a towed vessel behind.  After carefully studying the movement of the radar signals for both vessels we concluded the second one was being towed.