MarQuip, a Dutch company that designs and produces superyacht exhaust systems, is keenly aware of the new International Maritime Organization’s (IMO) emissions regulations that went into effect on January 1, 2016. The adoption of IMO Tier III rules for yachts less than 500 gross tons and more than 24m (79‘) of waterline length was delayed for five years. Finally going into effect January 1, 2021, the rules require a 74% reduction in nitrogen oxide (NOx) emissions compared to Tier II levels. The engines in vessels for which the keel was laid on or after January 1, 2016, must be compliant with IMO Tier III to travel in so-called NOx Emission Control Areas (NECAs), which currently cover the coast of North America and the Caribbean island territories of the U.S. and, starting January 1, 2021, also the North and Baltic seas.
MarQuip says that according to marine engine manufacturers, “The new IMO Tier III regulations cannot be fulfilled solely through adaptations within the engines themselves, so posttreatment of exhaust gases has to provide at least part of the answer.” To achieve lower NOx emission levels, yachts that exceed the prescribed length and tonnage limits now need exhaust aftertreatment, aka Selective Catalytic Reduction (SCR). While the technology is readily available, often the space to fit it in is not. On new builds the engineroom(s) can be designed for the required components, but it’s a different story if an existing vessel has to be retrofitted for Tier III compliance. That job requires planning and clever solutions to minimize the need for structural surgery (see “Fitting It In,” PBB No. 186).
MarQuip addresses this challenge with a new bypass diesel particle filter (DPF) that has a purported soot-reduction capacity >97%. Called the Clean Navigator, it is an extension of the SCR needed to comply with IMO Tier III emission regulations while operating in NECAs. “We have developed this unit with [an] integrated bypass soot filter within almost the same dimensions as the most common SCR units,” said sales manager Daniël van Drunen. “When a yard buys engines, aftertreatment, silencer, water injection, and piping in separate components, yes, it needs a lot of space. But if you integrate the silencer in the SCR and the water injection in the SCR box, you can achieve really good results.”
When maneuvering close to shore in tight quarters such as marinas, a yacht engine operates in part-throttle mode, and the exhaust system emits gases above the waterline via bypass. This releases particulates into the air and onto the hull, and increases noise levels. So aside from reducing soot, MarQuip’s Clean Navigator also lessens above-the-waterline exhaust noise by approximately 10 dB, according to the company. The DPF is fitted with a smart control unit that acts on parameters such as back-pressure, speed, and rpm. Because the amount of exhaust gases when maneuvering—usually at a maximum of 20% throttle—is significantly less than at full speed, the unit can be compact. It can be integrated in new builds and refits alike or combined with custom third-party SCR installations.
Regarding the challenge of fitting more equipment into existing enginerooms for Tier III compliance, which is a challenge many yards and owners will face when refitting existing vessels, he did not mince words: “[You] can fit in all required equipment, but you need …[a] smart plan and a good system integrator.”
MarQuip B.V. Nieuwland Parc 10n, 2952 DA Alblasserdam, The Netherlands, tel. +31 (0)78 681 09 75,