Evaluation of Tug Escort Schemes Using Simulation of Drifting Tankers

The ability of tug escort vessels to save oil-laden tankers that become disabled in Prince William Sound, Alaska, is tested using a simulation of the drift path of the tankers. Tug escort schemes are intended to save tankers that have lost steering or propulsion by attaching a line and either holding the tanker from running aground until a repair can be made or towing the tanker to port. The ability of an escort tug to save disabled tankers depends on its position at the time of the accident, the location, speed and direction of the tanker at the time of the failure and the wind and current conditions that changed dynamically during a save attempt. To accurately test the save capability of a proposed escort scheme, a simulation of the Prince William Sound is created that models dynamic changes in environmental conditions and thus the movement of the tanker. The simulation is used to test a new escort scheme that had been proposed for Prince William Sound.