Exxon Valdez Oil Spill
The T/V Exxon Valdez
The Tanker / Vessel Exxon Valdez (EV) was a typical modern tankship of all welded steel construction. The EV was delivered to Exxon on December 11, 1986 and was the largest ship ever built on the West Coast of the United States. It was the first of two Alaska-class tankships designed and built for the Exxon Shipping Company by the National Steel and Shipbuilding Company in its San Diego shipyard. The vessel was designed to meet standards of the International Convention for the Prevention of Pollution from ships of 1978. These standards provided for protectively located ballast tanks, maximum tank compartment length, and damage stability. The EV was certified by the US Coast Guard for the transportation of crude oil products and combustible liquids Grade B or lower.
The EV measured 987 feet long, 166 feet wide, and 88 feet deep from the main deck to the flat keel. The tankship had a maximum draft (loaded draft) of 64.5 feet. At maximum draft the ship could transport about 1.48 million barrels (25238.1 gallons) of crude oil per voyage.
The ship was propelled by an eight-cylinder, reversible, slow-speed Sulzer marine diesel engine. The main engine was rated at 31,650 brake horsepower which sustained a sea speed of 16.25 knots (18.7 mph) at the engines maximum continuous rating of 79 rpm. The main engine was designed to operate on No. 2 diesel oil or heavy fuel oil. The main engine crankshaft was directly coupled to the propeller shaft driving a single, five-bladed propeller. (NTSB Marine Accident Report)
An inspection of the vessel in dry-dock at the National Steel and Shipbuilding Company shipyard in San Diego was conducted on August 29, 30, and 31 and September 1 of 1989. (see pictures at bottom) The inspection revealed that the forepeak tank was severely holed and that center cargo tanks 1, 2, 3, and 4 were ripped open over almost their entire lengths. Although holed, center cargo tank 5 sustained the least damage. Starboard tanks 1, 3, and 5 were also severely holed, as was starboard ballast tank 2. Starboard ballast tank 4 sustained minor damage, resulting in a small opening at the bottom of the forward bulkhead. The double bottom below the starboard slop tank was also ripped open. (see diagram at top)
Most of the loss of cargo from the EV occurred during the first 8 hours. Initial measurements by the chief mate (James Kunkel) about 30 minutes after the grounding indicated that 115,000 barrels of the 1,263,000 barrels loaded had been lost. These calculations were based on the gauge readings made in the cargo control room. By 0600, gauge readings indicated about 215,000 barrels had been lost. (NTSB Marine Accident Report)