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Techno-Economic Assessment of Hull-mounted Sonar for Oil-spill Risk Control

Despite continuous efforts to improve shipping safety, groundings are still the prime cause of large scale oil pollution of the marine environment. As the bridge operator remains the most important part of navigation, the provision of tools which promote his understanding of the threats which lie ahead of the ship has become a permanent challenge. In this work, the use of a hull-mounted forward-looking sonar as a navigational aid for grounding avoidance and ultimately as an associated oil-spill risk control option for oil tankers is examined according to the Formal Safety Assessment (FSA) approach. In this context, the sonar's oil-spill risk reduction potential and its overall cost were estimated and assessed against the Cost of Averting a Ton of oil Spilled (CATS) criterion. It was found that the currently available sonar technology has a maximum detection range which is adequate for the avoidance of powered groundings in the case of small-sized oil tankers only. However, for this ship size category, the attained oil-spill risk reduction was found to be low and sonar use was proved to be cost ineffective. However, it was found that sonar technology will offer sizable oil-spill risk reduction in large-sized oil tankers and their requirement for longer sonar detection range can be easily met cost-effectively as an oil-spill risk control option for ships of this size.