Inconsistent Rules Create Uneven Application of Standards. (Captain) Jeff Cowan explores the how and why of the safety gap that comes as a direct result. Oil tankers and cargo vessels face a number of oil spill prevention regulations especially along the U.S. coast. Surprisingly, many of the regulations governing T-2 and T-3 sized tankers which carry between 120,000 and 146,000 barrels of oil do not apply to the new Articulated Tug Barges (ATBs) that may carry as much if not more (400,000+ barrels).