The terrorist attacks of September 11, 2001 heightened awareness about the vulnerability to terrorist attack of all modes of transportation. Port security has emerged as a significant part of the overall debate on U.S. homeland security. The U.S. maritime system consists of more than 300 sea and river ports with more than 3,700 cargo and passenger terminals. However, a large fraction of maritime cargo is concentrated at a few major ports. Most ships calling at U.S. ports are foreign owned with foreign crews. Container ships have been the focus of much of the attention on seaport security...