ABSTRACT
Shortly after midnight on March 24, 1989, the Exxon Valdez went aground in Prince William Sound. This paper presents the reconstruction of the ship’s path and control inputs for the half hour preceding its grounding. Additionally, this paper presents engineering analyses of the grounding which quantify vessel damage, and interpret this damage to determine how the vessel encountered the reef.
The quantitative analysis of the ship’s path and control inputs includes an analysis of the ship position, time of position, speed, heading, and rudder setting. The analysis is based on interpretation of evidence such as reef survey data, printouts from the vessel’s instrumentation, and witness statements, and includes a numerical simulation using a hydrodynamic model for the Exxon Valdez, calibrated from sea trials. The ship track analysis predicted the rudder position required to produce the observed vessel responses.
The engineering analysis of the grounding began with a quantitative inspection of the vessel in dry dock, prior to any repairs. Analyses of inspection data showed that vessel damage occurred in three separate phases, only the first two of which contributed to energy dissipation which brought the vessel to rest; the third phase was caused by tidal variation and wave action.
