What is an ATB?

(click photo to enlarge)

Crowley's Articulated Tug Barges (ATB) consist of a tank vessel (barge) and a large, powerful tug that is positioned in a notch in the stern of the barge. The tug propels and maneuvers the barge. Unlike an ITB (Integrated Tug/Barge) where the tug and barge are locked together in a rigid connection and became for practical purposes one unit, the ATB has an articulated or "hinged" connection system between the tug and barge, which allows movement in one axis, or plane in the critical area of fore and aft pitch. No such movement is possible with an ITB unit. Crowley's ATB's make use of the Intercon Coupler System to mate the tug with the barge.