Sound is a key biological function for most marine animals as it helps them communicate, reproduce, navigate and avoid any predators. Over the recent years there has been an increase interest in scientific research to understand the potential short and long-term negative effect that anthropogenic underwater noise might have to the already noisy ambient environment filled with natural sounds from waves, winds, and animals.
Although the research has acknowledged uncertainties and complexities regarding the potential effects of underwater sounds from ships, the International Maritime Organisation has shown an increased appreciation of this issue and has been taking a number of actions to reduce commercial vessels noise.
In 2014, the IMO adopted Guidelines that focus on propeller design and modifications to reduce cavitation, as well as hull design, onboard machinery and operational measures to reduce the add on impact of ship noise on marine life.
Most of the ship’s underwater noise is caused by propeller cavitation. Cavitation is an undesirable phenomenon on marine propellers. It impacts negatively the energy efficiency of a ship as it increases its hydrodynamic resistance, changes its flow, causes vibration, noise and erosion. Hence addressing propeller cavitation is a win-win situation as it does not only reduce underwater noise, but it also addressed climate change concerns.
The IMO has also taken into account noise through adopted ‘’ Particularly Sensitive Sea Areas’’ and ship routing measures to protect marine life from ship strikes during breeding seasons, by keeping ships away from specified areas.
Furthermore, an advanced broad collaboration and partnership amongst the industry, governments, scientist and shipbuilders to address commercial vessel noise is being currently carried within the new work plan of the IMO.
The UK Chamber of Shipping recognises shipping noise as an important marine conservation issue. As with many complex and evolving environmental issues, scientific and technical research is important to better understand and advance actions to address impacts. Therefore, the UK Chamber of Shipping is proactively collaborating with environmentalists, regulators, scientist and other industry bodies to fill the significant knowledge gaps and assist the progress made in the UK and the IMO.