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The Coast Guard is responsible for establishing, maintaining and operating aids to navigation (ATON) in the nation's waterways. Recent strategic reviews have identified a need to evolve the nation's ATON system towards greater reliance on electronic-based navigation systems, and away from physical aids and their supporting infrastructure. The current ATON system is comprised of numerous buoys, lights, cans, channel markers and other physical navigation aids. The number of visual aids has remained relatively constant over the past 30 years, without much consideration being paid to the technological advances of today’s state-of-the-market navigation equipment. Maintaining the current ATON system is a labor-intensive and costly expense for the Coast Guard and nation. Technology advances may also increase safety, with a corresponding reduction of accidents, by providing for even more accurate ship navigation.


The outcome of this project is the prototype Comparative Deep Draft Maintained Waterway Transit Risk Model. It compares ATON related collision, allision and grounding (CAG) and the risk of delaying ATON system alternatives. In addition, an approach is presented for using these risk results to compare the benefits of various ATON systems for a defined set of decision factors which include: CAG risk, delay risk and operational and safety costs. The model was vetted by Coast Guard, industry and government stakeholders, and discussions were held with operators from the Ambrose Channel, the main shipping channel for the Ports of New York and New Jersey.

In the initial exercising of the model with the Ambrose Channel, substantial differences in CAG risk were indicated between the current design and recommended updates. ATON evaluators determined the differences as being worthwhile in discerning meaningful comparisons between a waterway’s current design and modernization alternatives.

Before broadly applying the model to deep draft maintained waterways, it will need to undergo review, validation and benchmark development for selected waterway types. This will help to ensure the model is useful in predicting CAG and delay risk levels, and efficient in application to a specific waterway. As the model is applied to more ATON systems in deep draft maintained waterways, the results and conclusions are likely to become increasingly predictable.