(This is Part II of a two-part series on the Articulated Tug Barge from Robert P. Hill. Why The ATB? The ATB, or "Articulated Tug/Barge" unit is designed to combine the economics of tugboat and barge operation with the speed and weather-reliability of a ship. A hallmark of this concept that makes it different from the ITB or "Integrated Tug/Barge" is the fact that both the tug and the barge are truly independent vessels able to operate successfully even if not together. The tug is a full ABS or internationally-classed ocean tug, capable of meeting all SOLAS regulations where required. It can be made capable of towing and other traditional tug missions.