Oil and Gas Industry

Annual Report 2012 61Supply Vessels• Offshore Supply Vessels deliver drilling supplies such asliquid mud, dry bulk cement, fuel, drinking water, drillpipe, casing and a variety of other supplies to drilling rigsand platform. The vessels are also referred to as PlatformSupply Vessels (PSVs). They are the same thing, althoughsome industry participants like to think of a PSV as thelarger version of an Offshore Supply Vessel. OffshoreSupply Vessels are usually specified in terms of cargocarrying capacity, measured in dwt.Anchor Handling Tug (AHT)Purpose - A special purpose vessel equipped with towingmachinery used to tow offshore rigs and equipment fromone location to another and to set anchors for drilling rigs.Usually in small size to maximize its towing power.• Most have dynamic positioning capability although it isnot an absolute requirement. Dynamic positioned vesselsuse global positioning systems and computer controlledpropulsion systems that allow the vessel to maintain anexact position, regardless of wave and wind forces. Inaddition, a vessel that is typically built today can carrymore supplies than its 25 year old peers.Offshore Supply VesselPurpose - A specialized vessel used to transport supplyand carried out limited support roles such as pipe laying,rig moorings.Anchor Handling Tug Supply (AHTS)Purpose - A special purpose vessel similar to AHT,equipped with towing winches to tow and deployoffshore rigs and moorings. In addition, AHTS, whichare characterized by longer after decks, could be usedin limited supply roles.Platform Supply Vessel (PSV)Purpose - Vessel with large carrying capacity used totransport supply from port to oil platform.