The IMO Tier III regulations came into force on January 1, 2021, for all super yachts over 24 meters in length, while they have been in place for super yachts over 500 GT for some time. This environmentally friendly measure, while welcomed by the boating and yachting community worldwide, has led to a number of new challenges for yacht builders and yacht engine operators.

These requirements state that NOx emissions must be at least 70% below the maximum levels of the Tier II regulations. Smaller yachts are subject to space and size constraints: Simply optimizing the engine will not be sufficient in most cases, but a combination of techniques and technologies must be applied.

IMO Tier III regulations are set out in guidelines issued by the International Maritime Organization (IMO). The IMO is a United Nations agency and sets global standards for safety and environmental protection in international shipping.

How can yachts with diesel engines be brought into compliance with IMO Tier III?

Yachts emit large amounts of nitrogen oxides and volatile organic compounds. To meet the stricter Tier III requirements, NOx emissions must be reduced. This usually requires the installation of a selective catalytic reduction (SCR) system. An SCR system reduces NOx emissions by converting the harmful gases into neutral nitrogen and water vapor. Ultimately, all newly built yachts over 24 meters in length must comply with these regulations.