As regulations tighten, aging yachts face a choice: Adapt with eco-friendly upgrades or risk falling behind
The push towards sustainability in yachting is prompting shipyards to rethink every component of a vessel’s design. While much of the dialogue has focused on new-builds, the aging yachts in the existing fleet stand to benefit the most from upgrades to keep pace with modern standards and regulations.
To facilitate this, many shipyards now offer comprehensive assessments to evaluate a vessel’s sustainability potential before a refit. For instance, at Pendennis Shipyard, “We perform a complete holistic review pre-refit to propose improvements that can elevate the vessel’s sustainability,” explains Stephen Hills, commercial director at Pendennis Shipyard in the UK.
David Queva, group technical officer at Monaco Marine, notes an industry shift driven by growing awareness of sustainability and regulatory pressure. “More yacht owners, captains and engineers are requesting eco-friendly solutions, and crew members are increasingly involved in the conversation.”
MB92 Group’s “Refit for the Future” survey also reflects this trend. “The survey itself is a comprehensive evaluation aimed at identifying modifications, conversions, upgrades or new installations that can enhance the yacht’s environmental performance,” says Txema Rubio, MB92 Group commercial director. By studying the vessel’s operational profile as part of a long-term optimization plan, owners receive a detailed proposal that allows for informed decision-making. “They can choose the high impact ‘quick wins’ for immediate implementation and plan for more complex upgrades in coordination with the yard,” Txema adds.
The good news is that there is a whole menu of technological upgrades and sustainable solutions available to those considering their next refit.
Repowering
The IMO Tier III emissions regulations, effective since January 1, 2021, have pushed the marine industry towards more sustainable solutions. While many new builds are adopting hybrid or electric propulsion systems, there are still opportunities for existing yachts to improve sustainability without a full propulsion overhaul.
During refit, adding energy-efficient components like advanced battery systems, or utilizing surplus energy from main engines to reduce generator use, can make a significant impact. Pendennis, for example, integrates larger alternators and battery storage into existing yachts to cut generator reliance. On the 288ft Maltese Falcon, replacing outdated generators with more efficient models and adding a new electronic management system for the mains lowered fuel consumption and reduced emissions without altering the propulsion system itself.
Exhaust
Cleaning soot deposits from the hull can be an exhausting challenge for crew. Beyond aesthetics, soot particles pose serious health risks, including cancer, and they are bad for the environment. “Soot is the unburned carbon particles from the diesel fuel,” explains Daniel van Drunen, manager of sales at Xeamos, a Netherlands-based provider of emissions-reducing solutions.
Solutions like diesel particulate filters (DPFs) effectively tackle this issue by capturing particulate matter from the generators’ exhaust gases before they exit the vessel. Xeamos’ Zero Soot (ZS) technology can reduce soot emissions by up to 97 percent. Modern DPFs such as these use an electric heating component that keeps the exhaust gases at the optimal temperature for soot regeneration even at low engine loads. Demand for DPF systems has surged in recent years. “I think 70 percent of existing yachts don’t even have a diesel particle filter,” Daniel says.
Another solution in the exhaust system is selective catalytic reduction (SCR), which addresses nitrogen oxide (NOx) emissions by injecting a urea solution into the exhaust stream. Adding an SCR system lowers NOx emissions and helps yachts comply with IMO Tier III regulations, but they can be bulky, presenting challenges for space-limited refits. However, innovations are making these systems increasingly adaptable, even for yachts with small engine rooms. Yacht exhaust specialist MarQuip recently introduced what it calls the “most compact custom system for yachts under 500GT or 50 meters.” This design was prompted by an owner building a 92ft vessel, leading MarQuip to develop a solution that combines water injection within the SCR/silencer unit, maintaining the engine room’s original dimensions. The compact system, positioned above the engines, measured 7ft 6in by 4ft 7in.
Custom installations, tailored to a yacht’s layout, are also offered by companies like DeAngelo Marine Exhaust, which is currently installing a three-DPF system for an owner refitting their vessel for charter. “We visited the yacht before their yard period and 3D-scanned the whole engine room. The engineering team then designed the exhaust layout,” explains CEO Justin Montes.
HVAC
According to the Yacht Environmental Transparency Index (YETI), up to 78 percent of a yacht’s annual energy consumption comes from its hotel load, with heating and air conditioning being the primary culprits. For yachts with older HVAC systems that operate with fixed cooling capacity, upgrading to energy-efficient models during refits can make a big difference in consumption — some can cut energy draw by 50 percent or more.
One notable technology is the variable refrigerant volume (VRV) direct expansion system, which uses variable speed compressors and smart software to provide “Capacity on Demand,” optimizing cooling capacity based on actual need. For instance, if guests gather in the salon, that area can be prioritized for air conditioning. Hunter Parker, sales manager at Termodinamica, explains, “If we’re looking at a 60-meter (197ft) yacht with a traditional chilled water system drawing 60 kilowatts, we can typically reduce that to 30 kilowatts, often achieving 60 to 70 percent greater efficiency.”
Another advantage of this system is its compact size, often freeing up space for additional equipment. “We did a refit on a large yacht, and the chief was thrilled to fit a shiny new toolbox in the space saved by replacing the compressors,” Hunter adds.
Stabilization
Following HVAC, the second-highest energy consumer on most vessels is the stabilization system. Historically operated through hydraulic power, many are now switching to electric systems for greater efficiency. Monaco Marine recently replaced the gyroscopic stabilizers on a 138ft Palmer Johnson with four zero-speed electric stabilizers.
In late 2023, Quantum Marine Stabilizers launched the F45 Integrated Hybrid Power System, combining hydraulic and electric technology to enhance sustainability. Unlike traditional hydraulic systems, which can draw up to 40 percent of their maximum power even when not in use, the F45 consumes less than 1kW in standby mode and utilizes the proprietary MESS (Mass Energy Storage System) for energy storage and recovery. The recently introduced e-FIN system also improves energy efficiency by capturing and reusing excess energy generated during fin movement, with nearly 80 percent of the energy used to move the fin being recoverable, depending on sea conditions. “At zero or slow speeds, it is 60 percent more efficient than a traditional hydraulic system,” says Katie Ross, business development manager at Quantum. She adds that the company recorded up to an 80 percent recovery rate in underway mode when the fins are coming back on.
Water
On modern yachts, every type of water — black, gray or potable — can be repurposed for sustainable use. Plastic bottles have been standard for drinking water, resulting in waste — up to 54,000 bottles and 2,000kg of plastic yearly on a 50-crew yacht. Filtration systems like SpotZero’s double-pass watermakers now turn seawater into ultra-pure drinking water – which also means no more heaving cases of bottled water up the passerelle. Water Without Waste also offers plastic-free systems, and AquaTru even adds boiling, chilled, ambient and sparkling options.
Black water is also getting an upgrade. MARPOL regulations set discharge standards, but 196ft S/Y Sarissa surpasses them with its ACT2 reclamation system, invented by a NASA engineer and a former superyacht captain. While the crew isn’t drinking it (yet), add a nano filter and the water would be fit for consumption — all while leaving zero sludge behind.
Then there’s gray water. Companies like ECOmar filter gray water through multi-stage processes, including micro-filtration and UV sterilization, making it safe for washdowns. And for laundry runoff brimming with microplastics, yachts can install PlanetCare’s microfiber filters to trap particles before they make it overboard. Feadship is also working on advanced scuppers to keep washdown water contained.
Coatings
Many refit projects include repainting, and thanks to advances in the marine coatings industry, there are now more sustainable options available, driven by standards set by the IMO regarding VOCs (volatile organic compounds) found in paints, varnishes, waxes and cleaning supplies that leach chemicals into the environment.
AkzoNobel recently introduced Awlgrip HDT, a high-performance topcoat. “It is the first yacht topcoat that is VOC-compliant, using lower VOCs than traditional options,” said Matthew Anzardo of AkzoNobel’s global yacht management. “It’s also repairable and durable, which means you can extend the time between dry docks.”
Another emerging technology is LSA (low solar absorption). These coatings “contain unique pigments that help reduce infrared heat being absorbed. You can have that darker color look without the extra hotel load,” Matthew adds.
Windows
UV film enhances yacht efficiency by reducing the interior heat load. “By mitigating the influx of solar heat into the yacht, the HVAC system operates with reduced effort to maintain a comfortable temperature,” says Ryan Tounsley, director of marine at XPEL, which installs films on homes, automobiles and boats. “This leads to lower energy consumption, resulting in fuel savings, and decreased wear and tear on the HVAC.” Additionally, these films protect the interiors by blocking up to 99 percent of UV radiation, which contribute to fading of fabrics, leather and wood interiors. Designed to selectively filter specific wavelengths of light, UV films can allow visible light in while blocking heat-producing rays, so cabins stay naturally bright, reducing the need for artificial lighting and further conserving energy.
Materials
Sustainable material choices are essential when considering the full picture of a yacht’s environmental footprint. Teak, long considered the gold standard for decking, now faces scrutiny. Alternatives like laminated teak from reforested sources and carbon-negative cork decking, offered by Teakdecking Systems, are gaining favor, with recent refits such as Monaco Marine’s 154ft Mangusta adopting them. (For more on innovative decking products, see our feature on page 30.)
Interiors are also evolving. Destry Darr Pethtel of Destry Darr Designs, who led the refit of the 112ft Westport Emilia, integrated “low-impact materials such as low VOC and recycled wall coverings, Cambria quartz surfaces, and wool carpeting,” proving that “luxury and sustainability can coexist harmoniously.”
Other sustainable innovations include EcoSylk by SYLKA, which turns discarded fishing nets and plastic bottles into silk-like carpets; Nature Squared reimagines waste materials by using natural elements like eggshells and bamboo for wall panels and furniture; and Merritt in Ohio crafts cabinetry and beams from reclaimed “sinker” logs — submerged in rivers since the 1800s — as seen in the refit of the 281ft Cakewalk, now Aquila.
“Many small moves equal a large sum of ecological care,” says Destry. “Making a difference is about consistent, thoughtful efforts rather than grand, singular gestures.”
Whether it’s a full sustainable overhaul or a few targeted upgrades, refitting a yacht is sustainability in action. As Balk Shipyard CEO Evan Kortmann aptly puts it, “Rebuilding is a study in upcycling,” a chance to revive, while sidestepping the environmental cost of a new-build.
While captains and crew may not always hold the final say, their insight is invaluable, particularly into eco-friendly choices that not only benefit the owner’s wallet but also make life on board smoother. Understanding sustainable options isn’t just good stewardship; it’s a way to shape a greener, more efficient future on the water.