Under Washington State law, tankers and cargo ships transiting through Puget Sound require a tug escort east of Port Angeles.
Pilots board each vessel shortly after tug escorts arrive.
This scenario entails a collision in the precautionary area northwest of Port Angeles and the pilot boarding area. The precautionary area is a convergence zone where inbound and outbound vessels come into close proximity to one another as they transition from one shipping lane to another. It is an area of high risk and great concern to state regulatory agencies who monitor traffic in the Sound. The current model corresponds to tide patterns on that day while the circumstances of the collision are based on actual near misses reported to Department of Ecology. Other assumptions include a 10 hour delay before containment of the spill occurs and a draining of 300,000 gallons of Alaska originated, crude oil.