Making noise about URN reduction
With underwater radiated noise reaching new levels, the shipping community is searching for practical ways to reduce its impact.
Marine pollution takes many forms, but one particular impact on ocean life remains largely unaddressed: noise. Upticks in noise levels can have adverse effects on marine life, including altering their behavior and negatively impacting their ability to communicate, forage and avoid predators. Commercial shipping has been a principal factor in underwater radiated noise (URN), which has doubled background noise levels over the last 40 years.
The road to developing URN guidelines
In April 2014, IMO released URN reduction guidelines—an important first step that provided generalized instructions to commercial shipping companies. However, these guidelines are not mandatory, and are in need of updating.
To help standardize the process of assessing and addressing URN, scientists, policy makers and class societies like Bureau Veritas, recently met for a series of workshops. The first took place in Halifax, Canada in November 2018 and was followed by a larger workshop at IMO’s London headquarters in January and February 2019.
Key paths to reducing impact
One of the main areas identified for noise reduction during workshops is ships’ propellers. Marine professionals are trying to design propellers that are quieter, but allow ships to remain fuel-efficient. Engines, auxiliaries and even ship structure are other areas of improvement, with re-designs in the early R&D stages. In the meantime, temporary URN reduction measures are possible, such as ships sailing slower to reduce noise.
Along with advising clients and developing its own URN class notations, Bureau Veritas aims to communicate the importance of URN reduction to the shipping community at large. The goal is to provide a value-added service that helps shipyards and owners by providing dedicated, predictive URN calculations at the design stage, so ships can achieve compliance and limit their environmental impact from the start.
The future of URN reduction
In addition to workshops and individually funded research, governments worldwide are beginning to take an interest in URN. A notable example is PIAQUO, a follow-up to the EU-funded AQUO project, which aims to implement methodologies and tools conceived during the AQUO project. A three-year project, PIAQUO will also involve port authorities, and work to build incentives to help shipowners reduce URN.
Some companies are also making direct pledges to reduce URN caused by their ships. In France, nine shipowners have signed onto the French government’s Sustainable Actions for Innovative and Low-Impact Shipping (SAILS) charter. Signatories have committed to reducing URN by conforming to IMO directives and earning relevant class notations from Bureau Veritas and others.