MarQuip and IMO Tier III for smaller superyachts

The IMO Tier III requirements came into force for all superyachts on 1 January 2021. While this eco-friendly measure is globally welcomed by the boating community, it has resulted in a host of new challenges for the builders and operators of yacht engines.

Thanks to our many years of experience and unrivalled expertise in yacht exhaust systems, MarQuip has responded to those challenges with a wide range of innovative solutions.

The IMO Tier III regulations regarding nitrogen oxide (NOx) emissions took effect for all large vessels with an engine output of 130 kW or more which had their keel-laying on or after 1 January 2016. They specify that NOx emissions must be at most around 70% lower than the maximum under the Tier II regulations.

Originally applicable only to vessels with a gross tonnage of more than 500, since the start of 2021 they also apply to all yachts above 24 metres, no matter their volume. Smaller boats are subject to particular constraints in terms of space and size: simply tuning the engine will not be sufficient in most cases, and a combination of techniques and technologies will have to be deployed instead.

“Basically the issue we’re dealing with is that after-treatment units are heavy and bulky, and smaller yachts have smaller engine rooms,” says Jeroen van der Matten, MarQuip’s general manager. “On larger boats, engine manufacturers are producing engines with standardised after-treatment. This has the added value of allowing producers to deal with a single supplier, and facilitates certification, servicing and warranty issues.”

Added value

“With yachts below 500 GT, however, there will often not be enough space for these standard solutions,” Jeroen points out. “This is where MarQuip can provide serious added value: we can deliver custom solutions that will fit each engine room, and we have the capability to combine a silencer and an after-treatment system in a single unit – both things that engine manufacturers cannot.”

MarQuip is especially well-placed to make a difference in this regard. The company has vast experience in a wide range of custom exhaust projects and in merging existing components with our own solutions. Whichever engine or after-treatment system a yard opts for, MarQuip knows how to combine it with our own tailor-made solutions.


“We would also like to challenge the engine manufacturers to come up with better options, better solutions,” Jeroen continues. “Normally engines and after-treatment units are delivered as big standardised boxes and that’s it – more often than not they will be slightly adapted versions of solutions originally designed for onshore applications. This may work for tankers or large commercial vessels, but is a far cry from what many owners of smaller yachts need. The industry could benefit from a more maritime-centric perspective.

“There are very few superyachts on the water with the latest after-treatment systems; they are mostly still being built. The first problems will come up – and be managed – over the coming few years. We are already seeing a lot of discussions about the best materials to use, best ways to deal with corrosion, things like that. An example of something that will become more important in the future is the smell produced by the after-treatment. These are all new topics, new problems and new challenges. In partnership with its customers and partners, MarQuip is already providing the solutions.”

Have a look at the update below on the LinkedIn page of SuperYachtTimes with regard to IMO TIER III

Have a question?

Jeroen van der Matten

General manager

Techniques we use

  • Back pressure control

  • Noise attenuation

  • Anti vibration control

  • Exhaust cooling control

  • Emission control

  • Exhaust Heat Exchanger

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Need a new exhaust system for your yacht or have a general question? Let us know and call us on +31 (0)78 681 09 75 or email us on

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