Throughout the world wherever oil and gas is discovered, a support industry will develop and evolve with the needs of industry and government regulation. In the Gulf of Mexico, a large variety of marine vessels transport goods and provide services to exploration, development and production activity, and play an important role in the economic and ecological impacts across communities. The spatial and temporal dynamics of the logistics network is complex and dynamic and closely related to the magnitude, duration, type, and sequence of offshore workflows and activities. The purpose of this paper is to develop a methodological framework to quantify the number of offshore supply vessel and crew boat departures by activity across the Gulfs coastal regions in support of the oil and gas industry. The logistics network is modeled as a linear time-invariant deterministic system and implemented using an input-output model. We provide a methodological framework to quantify the magnitude and distribution of service vessel trips to forecast port activity. This is the first integrated modeling study on service vessel trips in the Gulf of Mexico and special attention is paid to the analytic framework, model assumptions, and limitations of the analysis. Generic examples illustrate the model implementation. (C) 2010 Elsevier Ltd. All rights reserved.