Kirby Offshore Marine is the largest United States operator of coastal tank barges and towing vessels participating in the regional distribution of refined products, black oil, and petrochemicals. Kirby's coastal fleet operates along the U.S. coastal network and calls on ports along the Atlantic, Gulf, and Pacific coasts. Kirby's offshore fleet includes approximately 23 Articulated Tug/Barge units (ATB's) which connect the tugboat and barge, enabling the tugboat to push, rather than pull the barge at sea. ATB's can operate safely and efficiently in a wider range of sea conditions than conventional tugboat and barge units, resulting in faster transit times, better fuel economy and fewer operating delays. Since 2015 Kirby has placed 6 new state-of-the-art ATB's into service with a combined tank capacity of over 800,000 barrels.