Systems-Theoretic Accident Model and Processes (STAMP) Applied to a U.S. Coast Guard Buoy Tender Integrated Control System

Abstract

The Systems-Theoretic Accident Model (STAMP) developed by MIT's Dr. Nancy Leveson was applied in this thesis to a ship navigation control system used on U.S. Coast Guard buoy tenders. The legacy system installed on the Service's 16 sea-going buoy tenders experienced numerous incidents that had potential to be hazardous to the ships and their crews. Faced with the dual needs of ensuring safety of mission execution and restoring confidence in the overall ship control system, yet faced with a limited budget, Coast Guard decision-makers elected to conduct a partial recapitalization of the system's hardware and software. This thesis explores the application of system safety methods to analyze the legacy system on the seagoing buoy tenders. An accident analysis of a particular incident was conducted using STAMP methodologies, and its results were compared/contrasted with the results of a more traditional root cause failure analysis that was contracted by the Coast Guard following the incident. Several added insights pertaining to system safety and process improvement were obtained by using STAMP. Additionally, a hazard analysis was performed on the control system using STAMP techniques. This hazard analysis yielded 92 specific design requirements that may be incorporated into future system upgrades on these or similar vessels. The thesis concludes that STAMP methodologies are appropriate to generate actionable recommendations for future control system upgrades on U.S. Coast Guard buoy tenders. It also concludes that STAMP techniques may lead to safer controls in the greater hierarchical control structure for shipboard buoy tending operations. Finally, suggestions are made for future research/application of STAMP principles in the Coast Guard's management of operational safety, asset acquisition, and cybersecurity.