Oil Spill Risks From Tank Vessel Lightering (1998) / Chapter Skim
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2 Lightering Primer
2 Lightering Primer
Pages 28-49
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From page 28... ...
Most of this crude oil is imported from the Arabian Gulf, West Africa, the North Sea, and the Caribbean Basin (see Table 2-1~. In addition, some refined petroleum products are imported from the Caribbean, Canada, and Europe and lightered (along with refined products from the U.S.
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From page 29... ...
Accordingly, the committee anticipates only small increases in lightering of crude oil on the East Coast in the near term. Trends on the West Coast are expected to have little impact on overall
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From page 30... ...
Notes: Offshore lightering of imported crude oil for the years 1986 to 1994 are from MARAD Office of Statistical Analysis. More than 95 percent of these offshore imports are lightered in the Gulf of Mexico.
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From page 31... ...
The STBLs that supply the East Coast refineries are typically Suezmax vessels of 120,000 to 165,000 DWT (approximately 1 million barrels) or, in some cases, Aframax vessels of 80,000 to 105,000 DWT (approximately 650,000 barrels)
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From page 32... ...
Lightering companies usually supplement the crews by placing an experienced lightering master aboard the service vessel and, frequently, an assistant lightering master aboard the STBL. Workboats / Support Vessels Many companies conducting offshore lightering operations enlist the assistance of a workboat, especially when using nondedicated service vessels.
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From page 33... ...
Mariners who often navigate these waters have come to expect lightering operations in the traditional areas and can be expected to take appropriate precautions when approaching or transiting known lightering areas. The USCG was authorized by OPA 90 to create designated lightering zones, where single-hull vessels are permitted to operate for a period of time.
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From page 35... ...
These are the only lightering zones currently designated by national regulation, although other regulated areas can be (and are) designated at the USCG district level.6 Lightering on the East Coast Most lightering along the East Coast takes place in protected and semiprotected coastal areas, primarily Big Stone Anchorage in Delaware Bay and, to 5Single-hull tank vessels contracted for after June 30, 1990, are prohibited from conducting lightering operations anywhere (other than the designated zones)
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From page 36... ...
Offshore lightering is conducted off Montauk Point, New York; Cape Henlopen, Delaware; Cape Henry, Virginia; and Great Issacs, Bahamas. Lightering is conducted off Great Issacs when an STBL carries cargo that needs to be delivered at both East Coast and Gulf Coast refineries or when the weather off Cape Henry is not conducive to lightering operations.
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From page 37... ...
The lightering activity off San Diego began in 1996. Chevron Shipping Company, the only company now operating in this region, uses lightering to bring crude oil from the Middle East and the Far East to refineries in the Los Angeles and San Francisco areas.~° The typical STBL is a VLCC of about 300,000 DWT that lighters into service vessels of about 150,000 DWT, which then deliver crude oil to Chevron refineries.
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From page 38... ...
California officials and local environmental groups monitor West Coast lightering operations, and, impressed by the good safety record to date and by industry's cooperation in information sharing, they did not express serious concerns about the risk of spills from lightering. In the future, lightering activity levels are expected to remain stable unless and until there are major changes in the Alaskan oil supply.
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From page 39... ...
Coast Guard Control of Lightering Operations Geographical Area Designator Location Type of Control Designated lightering zones Traditional lightering areas Lightering anchorages Regulated navigation areas Outside U.S. Exclusive Economic Zone (EEZ)
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From page 40... ...
issued by the Coast Guard. All vessels must comply with all USCG regulations covering the operation of tank vessels.
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From page 41... ...
ITOL is a mechanism for the consensus-based development of industry standards, and among its accomplishments, is the publication of a supplement to the international guidelines on lightering operations (ITOL, 1990~. In addition, some major oil companies and independent oil transport companies have established
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From page 42... ...
In certain areas (e.g., the designated lightering zones) , the approach distances, wave heights, weather conditions, and other factors are i4A light, sweet crude of]
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From page 43... ...
(The personnel involved in lightering operations are described in Box 2-3.) By tradition and custom, everyone involved in the approach phase must agree that the conditions, vessels, equipment, and personnel are prepared and adequate for a safe operation; otherwise, the process comes to a halt until the problems are resolved.
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From page 44... ...
44 OIL SPILL RISKS FROM TANK VESSEL LIGHTERING During lightering operations, the service vessel is usually moored to the starboard side of the STBL. Before the vessels begin to maneuver to come alongside, a string of four fenders is rigged on either the starboard side of the STBL or on the service vessel (the industry-recommended approach)
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From page 45... ...
Inshore Operations Using a Tug-Barge Unit as the Service Vessel The approach phase of an inshore lightering operation, in which a tug-barge unit is typically used as the service vessel, differs in certain respects from the initial phase of an offshore operation. First, the STBLis always at anchor when lightering takes place.
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From page 46... ...
Many companies that operate service vessels employ a lightering coordinator, who is stationed on the STBL. This individual's role is similar to the role of an assistant mooring master.
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From page 47... ...
As with offshore lightering a DOI must be completed prior to any petroleum transfer within the territorial sea. Post-Transfer Phase Offshore Operations Cargo inspection, or gauging, is either performed while the hoses are being drained and disconnected or is delayed until the service vessel reaches its destination.
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From page 48... ...
The STBL then proceeds either to the next load port or to a destination port to discharge the remaining cargo. Cargo Delivery to Shore Facilities Following the lightering operation, the service vessel proceeds to a crude oil terminal ashore.
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From page 49... ...
Inshore Operations Using a Tug-Barge Unit as the Service Vessel The post-transfer phase for inshore lightering differs in two fundamental respects from the process for offshore lightering. First, cargo gauging of the service vessel is typically done after the barge reaches the discharge dock.
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