Frequently Asked Questions
Supertanker Technology Evaluation
Has the Unified Command considered using supertankers to help clean up the oil spill in the Gulf?
The Alternative Response Technology (ARTs) team, assisted by BP Shipping and the U.S. Coast Guard, has evaluated the potential use of supertankers in cleaning up the oil spill. The study resulted in several significant technical concerns, including timing, stability and effectiveness, hazardous materials handling/explosion risk; and fluid handling.
The ART team, BP Shipping and USCG concluded that the use of supertankers was not deemed technically feasible or safe for our spill response efforts.
What sort of evaluation was done?
The team has evaluated the feasibility of converting a supertanker into a vessel that could suction off the oil spillage, separate and decant it, then transport it to a refinery for further processing. The team modeled a vessel which was a 319,000 deadweight tons (DWT), double hull dry and liquid carrier, with a 2-million barrel capacity.
The team studied the use of a supertanker for our spill response operations where we have dispersed oil thinly spread out across large areas.
People are offering their tankers now—why isn’t the Unified Command using them immediately?
The supertanker would need time to be initially designed and engineered and then reviewed by regulators for this type of potential use in the GoM oil spill. The vessel will also need time for detailed engineering, fabrication and installation after its arrival in the GoM. The vessel will then need Flag Administration and Classification Society approval of the modifications.
Aren’t the tankers safe to use, since they’re already used to transport goods?
The team has significant concern about a supertanker’s stability and effectiveness in its modified state. We will be unable to load the supertanker any deeper than the ballast load line (generally 33% of summer DWT); tankers are now diesel-powered with a relatively high minimum speed (5-7 knots); any speed over 0.75 knots will cause booms to be ineffective; and the overall maneuverability of a supertanker—due to depth/draft issues—is compromised, especially in confined waters.
Hydraulic power units will need to meet hazardous areas requirements; wing ballast tanks will need proper design to carry recovered oil; and tank venting and hazardous area requirements also require more detailed evaluation.
With large volumes of recovered liquids, efforts will need to be made to lighten the supertanker to get rid of the liquids—currently all of the disposal sites are located at shallow draft sites (10-14 feet).
June 6, 2010