(www.MaritimeCyprus.com) Noise on ships
|Continuous noise onboard ships can have an adverse impact on human health. IMO adopted, in 2012, a regulation in the International Convention for the Safety of Life at Sea (SOLAS) to require ships to be constructed to reduce on-board noise and to protect personnel from noise, in accordance with the Code on noise levels on board ships. The Code sets out mandatory maximum noise level limits for machinery spaces, control rooms, workshops, accommodation and other spaces on board ships.|
The International Labour Organization’s Maritime Labour Convention (MLC 2006) also has requirements with respect to preventing the risk of exposure to hazardous levels of noise on board ships.
Underwater noise and impact on marine mammals
|Studies have shown that underwater-radiated noise from commercial ships may have both short and long-term negative consequences on marine life, especially marine mammals. The issue of underwater noise and impact on marine mammals was first raised at IMO in 2004. It was noted that continuous anthropogenic noise in the ocean was primarily generated by shipping. Since ships routinely cross international boundaries, management of such noise required a coordinated international response.|
In 2008, the IMO Marine Environment Protection Committee (MEPC) agreed to develop non-mandatory technical guidelines to minimize the introduction of incidental noise from commercial shipping operations into the marine environment to reduce potential adverse impacts on marine life.
Guidance on reducing underwater noise
|In 2014, IMO approved guidelines on reducing underwater noise from commercial shipping, to address adverse impacts on marine life. Given the complexities associated with ship design and construction, the Guidelines focus on primary sources of underwater noise, namely on propellers, hull form, on-board machinery, and various operational and maintenance recommendations such as hull cleaning.|
Much, if not most, of the underwater noise is caused by propeller cavitation (the formation and implosion of water vapour cavities caused by the decrease and increase in pressure as water moves across a propeller blade - cavitation causes broadband noise and discrete peaks at harmonics of the blade passage frequency in the underwater noise spectrum). On-board machinery and operational modification issues are also relevant.
The Guidelines also include definitions and underwater noise measurement standards.
When adopting the Guidelines, it was noted that there were still significant knowledge gaps, and that sound levels in the marine environment and the contribution from various sources was a complex issue, so setting future targets for underwater sound levels emanating from ships was premature and more research was needed, in particular on the measurement and reporting of underwater sound radiating from ships. The Committee invited interested Member Governments to submit proposals to a future session.