The Oriskany, a decommissioned aircraft carrier, became the largest ship intentionally sunk as an artificial reef May 17 when it was sunk approximately 24 miles off the coast of Pensacola, Fla.
After 25 years of service to the Navy in operations in Korea, Vietnam and the Mediterranean, the Oriskany now benefits marine life, sport fishing and recreation diving off the coast of the Florida panhandle.
The 888-foot ship took about 37 minutes to sink below the surface after strategically placed explosives were detonated at 10:25 a.m. CDT. The Navy developed an engineered sink plan to place the 32,000 ton ship upright on the ocean floor in a north-south orientation at an existing artificial reef site at a depth of approximately 212 feet, as requested by the state of Florida.
The Navy has been working with the U.S. Environmental Protection Agency (EPA), Florida’s Fish and Wildlife Conservation Commission, the Escambia County Marine Resources Division and the local Pensacola area community since 2003 and has conducted several scientific studies that demonstrated that the Oriskany would create an environmentally safe artificial reef.
The Oriskany was the first ship to be environmentally prepared using the EPA’s “Best Management Practices for Preparing Vessels for Use as Artificial Reefs,” and is also the first ship to receive a risk-based Polychlorinated Biphenyl (PCB) disposal approval from the EPA based on the agency’s findings that the reefing would not pose an unreasonable risk of injury to health or the environment.
A few days before the scuttling event, a Navy Explosive Ordnance Disposal team placed explosives and detonation equipment on 22 sea chest pipes and valves inside the ship, which were armed the morning of the sinking.
Oriskany Reef Data
Location: 22.5NM 133* from Pensacola Pass. 32.7NM 236* from Destin.
GPS Coordinates: N30:02.6, W87:00.4 or 30*02'38"N Lat, 87*00'25"W Lon
Orientation: Sitting upright with bow facing South.
Flight deck at mid-island = 135 feet
Top of forward bridge = 106 feet
Tip of aft gun platform = 97 feet
Top of forward gun platform = 95 feet
Top deck level on island = 71 feet
Highest part of structure = 68 feet
Hangar Deck = 150 feet
Bottom = 212 feet
Q. When was the Oriskany sunk?
A. May 17, 2006 .
Q. Where was the Oriskany sunk?
A. Approximately 24 miles off the coast of Pensacola. The site is part of the permitted Escambia East Large Area Artificial Reef site, which is 77 square miles. The location is
30* 02' 38" N Lat
87* 00' 25" W Lon
Q. How deep is the water where the ship is located?
A. Ex-ORISKANY was sunk at a depth of 212 feet, at mean low water. This provides a 61 foot navigational clearance at mean low water above the ship if the ship settles on its keel. A 55-foot minimum navigational clearance at mean low water is required by the Army Corps of Engineers permit.
Q. Will the Navy make other ships available to be sunk? When? What ships? How does the process work?
A. Yes, the Navy has identified additional inactive ships that potentially can be donated for sinking and use as artificial reefs. These ships are designated for disposal and may be utilized for artificial reefing, Navy deep-water sink exercises or domestic dismantling based on the needs of the Navy to further reduce the size of its inactive ship inventory. Additional ships may be added to this list as active ships are decommissioned and designated for disposal, and as other inactive ships currently held in a retention status are redesignated for disposal.
The Navy is currently working with the Atlantic States and Gulf States Marine Fisheries Commissions on an improved process for transfer of ships to states once all efforts to sink ex-ORISKANY are completed and lessons learned are incorporated in the transfer process. It is the Navy’s intent to start making some of these ships available for application in the fall of 2006.
Q. How was the Oriskany sunk? What types of explosives were used?
A. The sinking was conducted in accordance with an engineered sink plan. Main sea chest piping within eight machinery spaces were breached by simultaneous detonations of small C4 explosive charges in 22 locations internal to the ship. Progressive flooding sunk the ship. A one-mile stand-off zone was established around the ship during the sinking for the protection of public observers.
Q. Was the public able to see the sinking?
A. A stand-off zone was established around the perimeter of the ship during the sinking. The public was able to witness the sinking of the ship outside of this stand-off zone.
Q. How long did it take to sink the vessel?
A. From the time of the explosive charges until the vessel was no longer visible took approximately 40 minutes.
Q.Was the ship open to the public at any time prior to the sinking?
A. No, the ship was not prepared for general public tours. While the ship was accessible by a trained workforce conducting environmental and scuttling preparations, several fall and trip hazards existed which made the ship unsuitable for touring by the general public.
Q. Was a memorial held?
A. The Pensacola Bay Area Chamber of Commerce and the Naval Aviation Museum Foundation conducted a memorial service at the National Museum of Naval Aviation on May 13, 2006 .
Q. Have there been any modifications for diver safety?
A. Yes, FWC requested several modifications of the superstructure area that will be accessible to recreational divers. These modifications included removal of protrusions on bulkheads and the removal of glass from windows. No safety modifications were made below the flight deck.
Q. Will the Navy/State put mooring points on the ship to provide tie ups for diving?
A. This was considered by the State of Florida during its inspections of ex-ORISKANY. The state determined that there were adequate existing features of the ship that will facilitate anchoring points for dive boats.
Q. What was special about the process to prepare the ex-ORISKANY as an artificial reef?
A. The reefing of the Oriskany is the start of a completely new program for the Navy. It is the first vessel that the Navy will sink intentionally to form an artificial reef. The authority was recently granted in the FY 04 National Defense Authorization Bill (HR 1588 Sec 1013), which permits decommissioned ships stricken from the Naval Vessel Register to be transferred to States for use as artificial reefs.
This was also the first time the Navy was using the Draft National Guidance to prepare a vessel for reefing and the first time the Navy was seeking, for the reefing of the vessel, a risk based disposal approval under 40 CFR 761.62(c).
Q. How did the Navy clean the vessel?
A. The new national cleanup guidance identifies materials of concern that may be found aboard vessels, likely areas where they may be found, and cleanup goals. Using survey information, the Navy removed oil and fuel, asbestos, certain paints, and loose debris as recommended by the guidance. We also identified and removed all liquid
Q. What sort of remediation has been done to the vessel?
A. The environmental remediation actions are defined in the EPA’s BMP document. The Navy’s contract with Resolve Marine Group/ESCO Marine Joint Venture, awarded in Sep 03, was based on the draft EPA BMP document. The scope of work to prepare Oriskany for sinking as an artificial reef included removal/disposal of liquid hydrocarbons (fuels and oils) throughout the ship so that the ship is essentially petroleum free; removal/disposal of any loose or detached friable asbestos containing material; removal/ disposal of all capacitors, transformers or other liquid PCB containing components; removal and disposal of all loose paint accumulated on deck surfaces, bulkheads and overhead areas; removal/disposal of trash, loose debris, cleaning materials, and any floatable materials not permanently attached to the ship or that could be transported in the water column during sinking; removal/disposal of batteries, halon, mercury, antifreeze, coolants, fire extinguishing agents, black and gray water, and chromated ballast water. Most of this work was completed in December 2004, with final cleaning completed in Beaumont , TX , while the ship awaited tow in February and March 2006.
Q. Why did the Oriskany require special approval from the EPA to sink the vessel?
A. There are solid PCB containing materials onboard the ex-ORISKANY, typical of virtually all other ships built before the 1980s. After cleaning, some of these solid PCB containing materials still remain onboard the ex-ORISKANY. EPA has granted a risk-based disposal approval to allow solid PCB containing materials to remain onboard, based on the Navy’s demonstration that the risks to people using the reef, and plants and animals living and feeding on the reef, are acceptable. Navy was issued the risk-based Polychlorinated Biphenyl (PCB) disposal approval from the Environmental Protection Agency (EPA) Region IV on February 15, 2006 . The risk-based PCB disposal approval was issued pursuant to EPA regulations and is based on EPA’s findings that the disposal action will not pose an unreasonable risk of injury to health or the environment.