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The Drill Down, Issue #9: Evolution of the Offshore Supply Vessel

Graphic of a drill stringIntroduction

The creation of the Offshore Supply Vessel (OSV) came about from a necessity to support the offshore oil and gas industry on the Outer Continental Shelf of the United States.  This vessel type originated in the Gulf of Mexico but can now be found operating throughout the world. 

In this Drill Down, we will briefly explore the advent and evolution of the OSV throughout the years.  Future Drill Down issues will explore each of these categorical time frames of the OSV and their relation to regulatory requirements in greater detail.

What is an OSV?

Public Law 96-378 (signed October 6, 1980) formally defined an Offshore Supply Vessel as:

“...a vessel that regularly carries goods, supplies, or equipment in support of exploration, exploitation, or production of offshore mineral and energy resources.”

Prior to this, vessels of all types, including towing, fishing, cargo, passenger vessels as well as purpose built vessels, were engaged in the support of the offshore oil and gas industry.  As the industry pushed farther offshore and into deeper water, OSVs have evolved and now include relatively large, highly capable and technologically advanced vessels that conduct various operations.Photo of pre-PL 96-378 vessel (BOTRUC)

The evolution of the OSV can be better understood if examined from three different events in time:
1. Public Law 96-378 - October 6, 1980
2. 46 Code of Federal Regulations (CFR), Subchapter L - March 15, 1996
3. Multiple Service Certification - July 5, 2001

1. Public Law 96-378

Prior to Public Law 96-378 formally recognizing OSVs, various vessel types were utilized in the offshore oil and gas industry for the purposes of transporting supplies offshore.  In the early years, most offshore work was found relatively close to shore, allowing for smaller vessels to provide adequate service. An example of a pre-Public Law 96-378 vessel (Image (1), right).

Photo of a typical post-46 CFR Subchapter L vessel2. 46 CFR, Subchapter L

Over time the size, complexity, and capability of OSVs increased to meet the needs of the offshore oil and gas industry, including larger deck and liquid cargo capacities, specialization, and “purpose” built vessels.  Also, these vessels started seeking compliance with international standards to work offshore in foreign waters.  A typical post-46 CFR, Subchapter L vessel (Image (2), right).

3. Multiple Service Certification

The Eighth Coast Guard District, responsible for regulating Outer Continental Shelf Activities in the Gulf of Mexico, published a letter dated July 5, 2001, that established policy for certificating vessels for both OSV service under Subchapter L and another service under Subchapter I (Cargo and Miscellaneous Vessels).  This allowed Multiple Service Certification OSVs to engage in work beyond just the offshore oil and gas industry. An increase in the number of purpose built vessels also occurred, including anchor handling towing supply, commercial diving, well fracture/stimulation, subsea construction, and accommodation service, to name a few.  Typical vessels certificated for Multiple Service and their identified services are as follows:

Photo of a Liftboat
Self-Elevating Vessel (Liftboat)

Photo of a Commercial Dive Vessel (Saturation Diving)
Commercial Dive Vessel (Saturation Diving)

Photo of an Accommodation Service Vessel
Accommodation Service Vessel

Photo of a vessel multi-certificated as a Tank Vessel, OSV and Misc. Vessel
Tank Vessel, Offshore Supply Vessel, and Miscellaneous Vessel

Photo of a Subsea Construction Vessel
Sub-Sea Construction Vessel

Photo of a Well Fracture/Stimulation Vessel
Sub-Sea or Surface Well Fracture/Stimulation Vessel

Image Source Credits: 
(1) Offshore Magazine; (2) ECORD/IODP; (3) Montco Offshore; (4) Otto Candies; (5) Hornbeck Offshore; (6) Hornbeck Offshore; (7) Oceaneering; (8) Edison Chouest Offshore