AHT (Anchor Handling Tug)

An anchor handling tug (AHT) is an offshore support vessel built to set, recover, and reposition the mooring anchors of drilling rigs, semi-submersibles, and floating production units, and to tow them between locations. The defining figure is bollard pull, often 150 to 300 tonnes on a deepwater unit, generated by twin medium-speed diesels driving controllable-pitch propellers in nozzles. Most are AHTS variants that add a flush aft cargo deck and tanks, so the same hull supplies the rig as well as handling its anchors. A wide stern roller, sharp anchor-handling winches, and a clear deck distinguish the type from a plain harbor tug.