This industry employs various types of vessels, referred to broadly as offshore support vessels. Offshore support vessels generally fall into seven functional classifications derived from their primary or predominant operating characteristics or capabilities. These functional classifications are:

Platform Supply Vessels ("PSVs")

Serve drilling and production facilities and support offshore construction and maintenance work. They are differentiated from other offshore support vessels by their cargo handling capabilities, particularly their large capacity and versatility. PSV's utilize space on deck and below deck and are used to transport supplies such as fuel, water, drilling fluids, equipment and provisions. PSV's range in size from 150' to 200'. We operate one PSV currently in Southeast Asia. Large PSV's ("LgPSVs")range up to 275' in length with a few vessels somewhat larger and are particularly suited for supporting large concentrations of offshore production locations because of their large, clear after deck and below deck capacities. We operate 35 LgPSV’s (26 of which are owned by us) that function primarily in this classification but are capable of service in construction support.

Anchor Handling, Towing and Supply Vessels ("AHTS")

AHTS vessels are used to set anchors for drilling rigs and tow mobile drilling rigs and equipment from one location to another. In addition, these vessels typically can be used in limited supply roles when they are not performing anchor handling and towing services. They are characterized by shorter after decks and special equipment such as towing winches. Vessels of this type with less than 10,000 brake horsepower ("BHP") are referred to as small AHTS vessels ("SmAHTS"), while AHTS vessels in excess of 10,000 BHP are referred to as large AHTS vessels ("LgAHTS"). The most powerful North Sea Class AHTS vessels have up to 25,000 BHP. We own and operate four LgAHTS vessels all currently operated out of the North Sea. In addition, we also own and operate eight SmAHTV’s in Southeast Asia and two offshore Mexico.

Construction Support Vessels

These are vessels such as pipe-laying barges or specially designed vessels, such as pipe carriers, used to transport the large cargos of material and supplies required to support the construction and installation of offshore platforms and pipelines. Our 35 LGPSV's (26 of which are owned by us) fit the definition of pipe carriers. Our North Sea fleet has the distinction of being the only significant concentration of pipe carrier capable vessels outside of Scandinavian control.

Standby Rescue Vessels ("Stby")

Perform a safety patrol function for an area and are required for all manned locations in the United Kingdom sector of the North Sea. These vessels typically remain on station to provide a safety backup to offshore rigs and production facilities and carry special equipment to rescue personnel. They are equipped to provide first aid and shelter and, in some cases, also function as supply vessels. We own two vessels of this type that operate in this capacity in the North Sea.

Crewboats ("Crew")

Transport personnel and cargo to and from production platforms and rigs. Older crewboats (early 1980s build) are typically 100' to 120' in length and are designed for speed and to transport personnel. Newer crewboat designs are generally larger, 130' to 165' in length and can be longer with greater cargo carrying capacities. They are used primarily to transport cargo on a time-sensitive basis. We do not operate any vessels in this category.

Specialty Vessels ("SpV")

Generally have special features to meet the requirements of specific jobs. The special features include large deck spaces, high electrical generating capacities, slow controlled speed and varied propulsion thruster configurations, extra berthing facilities and long-range capabilities. These vessels are primarily used to support FPSOs, diving operations, remotely operated vehicles ("ROV"), survey operations and seismic data gathering, as well as oil recovery, oil spill response and well stimulation. Six of our owned vessels frequently provide specialty functions, and one managed vessel is currently chartered for specialty functions.

Utility Vessels

These vessels are typically 90' to 150' in length and are used to provide limited crew transportation, some transportation of oil field support equipment and, in some locations, standby functions. We do not operate any vessels in this category.

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