Revised regulations to reduce superyacht NOx emissions

The International Maritime Organisation (IMO), an agency of the United Nations, announced that the revised IMO Tier III emission regulation will come into action from 1st January 2016.

The 66th meeting of the IMO’s Marine Environment Protection Committee (MEPC66) agreed a revised course to regulate NOx emissions from shipping. To summarise, the IMO Tier III, will mean severe reductions in NOx emissions, approximately a 74% decrease compared with Tier II, and applies to yachts traveling in North American NOx Emission Control Areas (NECA) and the United States Caribbean Sea NECA. When these yachts travel outside of NOx ECAs, IMO Tier II regulations remain.

The IMO Tier III NOx regulation will be applicable to marine diesel engines installed on yachts constructed on or after 1st January 2016, when:

  • Length over 24 metre
  • GT  above 500
  • Intended solely for recreational purposes (check with Flagstate)
  • Engines over 130 kW  & not intended for emergency applications

From 1st of January 2021 all yachts above 24m and less than 500 GT travelling inside NOx ECAs also require compliance with IMO Tier III.

IMO stated, “The control of diesel engine NOx emissions is achieved through the survey and certification requirements leading to the issue of an Engine International Air Pollution Prevention (EIAPP) Certificate and the subsequent demonstration of in-service compliance in accordance with the requirements of the mandatory regulations 13.8 and 5.3.2.”

When speaking to Yachting Pages, Peter van der Heijden, managing director from NPS Diesel and her brand Zenoro explained, “Legislations like these are trying to align all emission regulations worldwide.  Many technologies already comply with PM (soot) and NOx regulations, and the marine industry has fallen behind, it is the last in the row.

“These enforcements will require investments from both manufacturers and consumers but in all, it will result in cleaner, more environmentally friendly generators. At Zenoro, we have noticed a lack of knowledge at superyacht shipyards in terms of the IMO Tier III regulation; many require more information on how they can become compliant. The required space for this additional exhaust after treatment will require optimisation and re-design of the engine room. At Zenoro we can assist the superyacht shipyards with this challenge.

“I predict that next year many new NECA’s will come in force, for example in the Mediterranean, so that all yacht propulsion engines and generators will have to be low in NOx emissions, as cars and trucks are today.

“As well as this, we have seen a recent trend in no-smell and no-soot filters that reduce the diesel smell and particulates given out by diesel engines, with over 50% of quotation requests involving treatment solutions. These filters have been used on cars and trucks for many years, yet are still not on all marine engines. Even the cheapest of cars are equipped with these particulate filters, so why would owners of such luxury assets as superyachts not want this benefit when enjoying their stay on their superyacht?”

Superyacht businesses such as Zenoro now have to invest time and money into their services to become IMO compliant, ensuring all NOx emissions are reduced as well as informing clients of these important updates.

NPS Diesel specialises in marine engines, premium and hybrid generators for superyachts, remote diagnostics and exhaust after-treatment solutions, and are working with Yachting Pages, a superyacht media group, to showcase their services to the industry.  

For more information, visit IMO.

To find out about Zenoro, visit

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