articulated tug-barge

An articulated tug-barge (ATB) consists of a conventional tug connected to a notched barge by a specialised articulated coupling system — proprietary designs include INTERCON, JAK, and Bludworth couplings — that locks the tug bow into a V-shaped or cylindrical notch in the barge stern. The coupling allows controlled pitch and roll articulation while preventing yaw and surge separation, so the combined unit handles like a conventional ship in open water whilst remaining divisible in port. The ATB concept offers the economic efficiency of a barge (low capital cost, no crew aboard the barge) with the seakeeping characteristics needed for coastal and nearshore ocean voyages. ATBs are widely used in the US Jones Act petroleum trade, carrying petroleum products, crude oil, or LNG along the East Coast, Gulf Coast, and Pacific Coast. Capacities typically range from 50 000 to 185 000 barrels. From a regulatory standpoint, the tug and barge are documented as separate vessels, which affects crew complement and certification requirements under STCW. The US Coast Guard (46 CFR Part 15) has issued specific guidance on manning ATBs. Where an ATB operates on international voyages, SOLAS Chapter II-1, Load Line Convention, and flag State requirements apply to both units individually. The ISM Code (SOLAS Chapter IX) applies to the operating company. See also the pusher-tug and barge entries.