Ship noise


Ship noise can have negative impacts – on both humans and marine life.

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.

Guidance on reducing underwater noise

The Marine Environemnt Protection Committee (MEPC 80) in 2023 The MEPC approved revised Guidelines for the reduction of underwater noise from commercial shipping to address adverse impacts on marine life.

The guidelines, issued as a circular, recognize that commercial shipping is one of the main contributors to underwater radiated noise (URN) which has adverse effects on critical life functions for a wide range of marine life, including marine mammals, fish and invertebrate species, upon which many coastal Indigenous communities depend for their food, livelihoods and cultures.

They include updated technical knowledge, including reference to international measurement standards, recommendations and classification society rules. They also provide sample templates to assist shipowners with the development of an underwater radiated noise management plan.

They provide an overview of approaches applicable to designers, shipbuilders and ship operators to reduce the underwater radiated noise of any given ship. They are intended to assist relevant stakeholders in establishing mechanisms and programmes through which noise reduction efforts can be realized. The previous guidelines were issued in 2014.

The MEPC approved the dissemination of an MEPC circular on Guidelines for underwater radiated noise reduction in Inuit Nunaat and the Arctic, developed by the Inuit Circumpolar Council (ICC). The guidelines recognize that Inuit Nunaat is a unique environment and adverse impacts to marine wildlife in this area from shipping noise may be significantly increased as a result. Sound levels throughout Inuit Nunaat are lower than elsewhere, making it more vulnerable to increases from industrial activity.

Implementing the guidelines

Following instruction from the MEPC, the IMO Sub-Committee on Ship Design and Construction (SDC) has agreed a work plan which envisages, among other things, identifying ways to implement the Revised Guidelines and to increase awareness and uptake; organizing an expert workshop on potential co-benefits and trade-offs that may exist between the reduction of underwater radiated noise from ships and energy efficiency; and developing a plan of action for further work.

Global Partnership for Mitigation of Underwater Noise from Shipping

IMO is currently designing a new project, the GloNoise Partnership project, which aims to address the issue of underwater noise from shipping. The project is currently in a preparatory phase and is expected to launch in mid-2023, subject to approval and funding by the United Nations Development Programme (UNDP) and the Global Environment Facility (GEF). If approved, the project is expected to receive $2 million in funding under the GEF International Waters focal area, and will be executed by IMO over a period of two years.  

The GloNoise Partnership will focus on building capacity in developing countries to implement the Guidelines for the reduction of underwater noise from commercial shipping to address adverse impacts on marine life.

Read more here: GloNoise-Partnership

Particularly Sensitive Sea areas and routeing measures

The issue of underwater noise and its effects on marine life is also taken into account through IMO adopted “Particularly Sensitive Sea Areas” (PSSAs). These are areas considered to deserve special protection, due to their recognized ecological or socio-economic or scientific significance, and which may be vulnerable to damage by ships. Ship routeing measures can be proposed for adoption in connection with a PSSA, to protect marine life.

IMO has also adopted a series of routeing measures to protect whales and other cetaceans from ship strikes during breeding seasons, by keeping ships away from specified areas. So these measures may also have a positive effect in terms of reducing the impacts of underwater noise. (Click for the article: Routing for Whales.)

Noise from dredging

Noise has also been discussed in the context of the work of the London Convention and Protocol on the protection of the marine environment from pollution from dumping of wastes and other matter. Dredging activities – dredged material is the main source of permitted wastes dumped at sea under these treaties - are also a source of anthropogenic noise.

The World Dredging Association (WODA) has submitted technical guidance on underwater sound in relation to dredging activities to the London Convention and Protocol Scientific Groups, providing advice to decision-makers, stakeholders and scientists on how to manage impacts of underwater sound, primarily from dredging.

Energy efficiency and underwater noise from ships 

An expert workshop was held on 18-19 September 2023 to examine growing opportunities to tackle Greenhouse Gas emissions and harmful underwater radiated noise in tandem. Co-chaired by Canada, France and the United States of America, it covered several themes: 

  • Reducing GHG and noise emissions
  • Energy efficiency by design and related new systems
  • Energy transition, operational optimizations and related solutions
  • Bridging the gaps and going to scale

A summary of the workshop discussions and presentations is available here

Read more