In-water cleaning guidance finalised by the IMO’s Pollution Prevention and Response Sub-Committee  

The guidelines are intended, in part, to support the global availability of safe and environmentally responsible in-water cleaning service we look forward to supporting our members in putting this guidance into practice and aim to facilitate the sharing of experience.   

The guidance on in-water cleaning of ships' biofouling finalised by the IMO’s Pollution Prevention and Response Sub-Committee is designed to help to shipowners, charterers, operators, crews and in-water cleaning service providers to safely plan and conducting in-water cleaning operations while addressing risks to the environment and ship coatings, including the conduct of pre-cleaning and post-cleaning inspections, as well as record-keeping and reporting. The guidance also provides information to many other stakeholders involved in the process of cleaning - such as authorities wishing to approve cleaning in waters under their jurisdiction.  

The guidance covers both in-water cleaning that may be conducted proactively (ie removing microfouling from a ship's hull and niche areas periodically to prevent or minimise attachment of macrofouling) or reactively (ie removing micro- and macrofouling from a ship's hull and niche areas as a corrective action). It covers the wide range of cleaning systems in use as well as anticipating future new technologies.  It includes guidance on the use of both diver-operated or remotely operated vehicles (ie cleaning carts) that remove biofouling from the ship – for example, the hull and the niche areas 

Critically the guidance looks at the capture of waste substances, which may be used for both proactive and reactive cleaning and is intended to protect the environment from the release of coating substances and non-native organisms in removed biofouling in accordance with the 2023 Biofouling Guidelines.  

Whilst the guidance is relatively comprehensive there is still work to be done. This includes developing a methodology for testing the compatibility between cleaning systems and various coating types and developing methods for assessing the minimum performance standard after systems enter into service. How to conduct in-water inspections to determine if in-water cleaning is needed also remains an outstanding issue which is likely to be of importance to our members.  

The guidance is expected to be approved by the IMO’s Marine Environment Protection Committee (MEPC) in April this year and will be made available to members shortly afterwards. We welcome feedback from members on the application of this guidance and the 2023 Biofouling Guidelines to ensure they are fit for purpose- particularly in light of the proposal to consider a legally binding framework for the control and management of ships' biofouling to minimize the transfer of invasive aquatic species that will also be considered at MEPC.