By David Cleary | ENVIRO FOCUS | JUNE 2009 |

In 2007, Associated Underwater Services (AUS) completed a detailed underwater investigation of the USS Chehalis (AOG-48), a WWII-era navel gasoline tanker resting on the bottom of Pago Pago harbor in American Samoa, and discovered a large quantity of product still aboard. Now the company wants the contract to salvage the vintage high-octane aviation fuel, but several obstacles stand in the diving company’s way.

The USS Chehalis, commissioned in 1944, was a 4,130-ton displacement, US Navy gasoline tanker ship. In October of 1949, while off-loading gasoline at Pago Pago Harbor on the Island of Tutuila, American Samoa, the 311-foot Chehalis suffered an explosion and began to burn. Because the fire could not be contained, the Chehalis was eventually towed away from the fuel terminal, at which point the USS Chehalis’ starboard anchor was deployed to hold her away from the dock facility as she continued to burn. The fire burned out of control for most of a day, at which point the ship was scuttled to extinguish the fire.

Today Chehalis, with more that 115,000 gallons of petroleum cargo and thousands of rounds of artillery shells on board, rests her starboard side in 160-feet of water approximately 310-feet offshore from the inner Pago Pago Harbor BP Oil South West Pacific Ltd. Fuel dock.

Some published narratives of the USS Chehalis burning and sinking state that the vessel was sold by the US Navy to the American Samoan Government (ASG) for $50 in 1955, but acting-director David Herdrich, of the American Samoa Historical Preservation Office, states that no completed contract or bill of sale has ever been located by the ASG, nor produced by the US Navy, to verify the sale of vessel to ASG.

Associated Underwater Services (AUS) is a Washington State-based commercial diving and underwater services company, located in Spokane and Seattle. It specialized in underwater construction, inspection and repairs on piers, piling repairs, ships, dams and other marine structures.

At the request of the American Samoa Environmental Protection Agency (ASEPA), AUS performed two inspections on the ship on 2006 and 2007. The first inspection determined the condition, orientation and structural integrity of the vessel, well as the existence of possible unexploded ordnance and the overall condition of the hull. One area of note was the cargo deck area, in relation to possible oil/gas products that may have sunk with the USS Chehalis. The vessel was found resting on its starboard side in 156 feet of water facing east. Despite having burned for 22hours before she was scuttled, her cargo deck was found to be in good condition. Eight of the ten cargo tanks were found with no visible damage.

During a 3-week period in 2007 AUS performed a second inspection, consisting of more than 65 decompression dives on the Chehalis. The diving crew consisted of five commercial divers utilizing a helmet-mounted underwater video camera. The diving platform consisted a twin engine, 38-foot workboat with surface supplied

(Left) Important components of community infrastructure sited within 300-meters of the USS Chehalis included the BP Oil South Pacific Ltd. Fuel Dock, the American Samoa Convention Center and the Pago Pago Harbor Port Facility, as well as a pre-school, the American Samoa Governor’s Residence, a hotel and restaurant and the only road connecting to the east of the island to west side of the island. (Right) After being submerged and in contact with salt water for 48-years, 155-145 octane Avgas still passes the “flame test”.

See this excellent article from Tunnelling Journal June 2010

Photos courtesy AUS.