Biofouling risk grows as more ships idle

A new study reveals the Covid pandemic and subsequent port congestion and increased vessel idling, coupled with warming waters means ships are at increased risk from biofouling.

The study from Swedish technology company I-Tech also shows the adverse effect that ship hull fouling has on vessel performance and that it gives rise to significant financial and environmental penalties for the shipping industry due to the increase in fuel consumption and carbon dioxide emissions.

The study shows over 40% of the vessels surveyed had a barnacle fouling coverage on the hull of more than 10%. This level of biofouling could be responsible for at least 110m tonnes of excess carbon emissions.

Only a few premium coatings offer guarantees based on 30 days idling and the vast majority may stop after 14 or 21 days. However, the study has proven that it is not uncommon for a vessel to be idling for more than 30 days, and in some cases even longer than 45 days.

With the industry still facing its looming IMO greenhouse gas reduction targets and the impending introduction of EEXI and CII for existing ships, these findings should serve as a reminder that a clean hull should be the first step of a fleet’s decarbonisation strategy according to I-Tech’s CEO, Philip Chaabane.

Sam Chambers

Starting out with the Informa Group in 2000 in Hong Kong, Sam Chambers became editor of Maritime Asia magazine as well as East Asia Editor for the world’s oldest newspaper, Lloyd’s List. In 2005 he pursued a freelance career and wrote for a variety of titles including taking on the role of Asia Editor at Seatrade magazine and China correspondent for Supply Chain Asia. His work has also appeared in The Economist, The New York Times, The Sunday Times and The International Herald Tribune.


  1. Most prudent ship owners and shipmanagers include underwater hull cleaning annually or bi-annually in the Preventive Planned Maintenance Software for container vessels in their fleet. This policy prevents potential speed/consumption claims from charterers.
    The underwater hull cleaning is witnessed by a Company representative and may even include a Hull Surface Roughness Report, after the hull cleaning is completed.
    So increase is in fuel consumption with corresponding drop in ship speed can be avoided with planned underwater hull cleaning.

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