Greenboats Pioneers Flax Boatbuilding

Hull infusionDieter Loibner | Professional BoatBuilder Magazine

Ready, set, go: Lucca Günther (left) and Theodor Martin monitor the infusion of a Flax 27 (8.20m) daysailer hull at Greenboats in Bremen, Germany.

Having blazed the trail for flax composites for a dozen years, Greenboats in Bremen, Germany, now leads a boat-building trend that is gathering momentum.

As the warming global climate yields increasingly severe and widespread consequences, the duration and quality of our collective future will likely depend on a combination of engineering solutions and fundamental behavioral adjustments. The lofty goal of “net-zero emissions” is popular among politicians and marketers, but so far it remains more aspirational rhetoric than attainable reality. That’s especially true for industrial enterprises that depend on resource extraction and fossil fuels for materials and manufacture. Recreational boatbuilding faces these general challenges plus the more delicate dilemma of depending on a healthy and inviting marine environment to market leisure products whose manufacture, use, and disposal contribute to its degradation.

Friedrich DeimannDieter Loibner | Professional BoatBuilder Magazine

Company founder Friedrich Deimann holds a piece of flax laminate in his office.

Even with those challenges, there are builders committed to reducing environmental impact while turning out boats customers are willing to buy. One of them is Friedrich Deimann; at a towering 67 (2.02m), he’s the founder and chief executive of the German company Greenboats. With approximately a dozen employees and scrambling to hire more, his firm specializes in constructing boats and other composite structures from flax and bio-based epoxy resins. (For previous coverage, see “The Quest for Cleaner Composites,” Professional BoatBuilder No. 188, page 54.)

Unlike fiberglass or carbon fiber, which are derived from energy-intensive petrochemical processes, flax is a plant that absorbs CO2 as it grows. When flax is processed and woven into fibers, its properties are favorable for composite construction in conjunction with various core materials. While not as lightweight and as stiff as carbon fiber, it takes less than 1% of the energy (measured in megajoules, MJ) to produce, and less than 9% of the energy required to manufacture glass fibers, according to a life cycle assessment (LCA) calculation done with the MarineShift 360 software (see below and sidebar). That LCA also ranks flax fibers and bio-based epoxy resin at the top of low-emission composite materials, close behind hemp, ahead of basalt fibers, and way ahead of glass fibers in polyester resin.

Masterpiece DeimannDieter Loibner | Professional BoatBuilder Magazine

Deimann’s masterpiece was a two-person kayak he built in 2010 that garnered lots of attention wherever it was exhibited.

About a decade ago, Deimann built his first flax boat, a two-person kayak, as his compulsory project to qualify as a master boatbuilder. “In the recent years we noticed that more people are jumping on the [flax] bandwagon,” Deimann told me during my yard visit last November. “At first, suppliers were laughing at me when I asked about bio-based materials. Back then, there was not much beyond the standard inventory they could offer. Today they are knocking on the door, but by now we have found systems that work well.” He said he works with several providers of fibers and plant-based epoxy, but Greenboats aims to become a supplier to other builders, developing proprietary biaxial prepregs, and sourcing yarn within Europe and custom weaving it in Germany.

Deimann’s journey to becoming a flax-composite guru started with his education at Fricke & Dannhus, a reputable yard near Bremen, because he “always wanted to become a wooden boat builder,” he said. “Wood is a beautiful material, and wooden boats have elegance and charisma, so you can be proud of the product. But building with wood requires considerable skill and does not figure in production boatbuilding.” Next, he went to Australia to teach students at a Montessori school how to build kit kayaks they could take out in Sydney Harbour. He returned to Germany to join the Meyer yard, which builds composite superyacht tenders with vacuum infusion. It was there that Deimann says he “learned to love and hate plastics. At some point, I lost interest in cutting and sanding fiberglass and carbon materials, and laminating made me sick. My girlfriend didn’t want to kiss me when I got home after work, because I smelled of styrene.”

While he admired the efficient production manufacture of multiple copies of a model that all came out of a single mold, he found the process and the materials wanting. Besides, he said, “it’s not just about the carbon footprint but also about a healthier work environment.” And that’s the first impression a visitor gets when walking through the door at Greenboats: no stink, no dust, no sticky floors.

Green BenteDieter Loibner | Professional BoatBuilder Magazine

One of the early copies of the popular 24′ Bente was built with flax fibers

To get to this sanctuary, Deimann worked through infusion hell in an unheated shed in Poland in the winter of 2015. There, he and some buddies were trying to infuse the hull of the first Green Bente, a special edition of a popular 24 (7.32m) trailer-cruiser designed by Judel/Vrolijk & Co. Design + Engineering (Bremerhaven, Germany). Living, as they say, on the bleeding edge, Deimann learned from failed infusions that highly reactive and viscous resins were unsuitable for large parts. “The tests hadn’t taken into account important aspects, like the moisture contained in natural fibers,” he said. “We were working in freezing temperatures while buckets were going off with smoke explosions. The resin was getting too thick, so we quickly had to lay new leads—not what you’d call a smooth infusion. There were air bubbles and pinholes, which required a lot of detailing afterwards. We took enormous risks, working day and night, but the boat was exhibited at the Düsseldorf show, in clear high-gloss coating.”

Düsseldorf was a big stage for this then-obscure building material, but it struck a chord with environmentally engaged attendees. Compared to the visitor dwell time on the fiberglass versions of the boat, guests who ventured into the cabin of the Green Bente 24 stayed much longer, Deimann observed. “It had a cork core that dampens sound and vibrations, and it smelled much nicer. Flax fibers emulate wood, and that’s better if you like to spend more time on a boat.” And at least one customer did. He bought the flax Bente and liked it so much that he asked Deimann to build garden furniture and a bathroom interior from flax composites.

Flax 27 upwindCourtesy Greenboats

The elegant Flax 27 daysailer during test sails in Northern Germany

This initial success led to the Flax 27 (8.20m), a spiffy daysailer priced at €149,500, or $165,000 (including 19% VAT). Built entirely from flax composite with recycled-polyethylene-terephthalate (PET) core, it has a lifting keel and a smooth exterior layer of cork on deck. Designed by Judel/Vrolijk, the first copy was launched in 2019, garnering attention for its elegant proportions, good performance, and the high-tech optics of flax under a glossy polyurethane-based clear coat. According to the spec sheet, the boat should displace 1,350 kg (3,000 lbs) but came in 150 kg (330 lbs) lighter, as Deimann proudly noted. “Our goal is to produce 10 of these boats at about two units per year,” he said. “We are looking to add larger versions, all with classic design, of course, because timeless lines don’t go out of fashion, which is important for a sustainable product.”

Infusing and Pressing

Press controlsDieter Loibner | Professional BoatBuilder Magazine

Electronic controls were added later to the vintage 1960s press.

During my visit, some of Deimann’s crew were readying the second Flax 27 hull for infusion. “Today we’re doing the inner skin,” said Theodor Martin, a cousin of Deimann and the lead on the job. “There are multiple layers of flax, consisting of uni[directional] and biax[ial], plus extra patches at the maststep, the keel attachment area, the rudder installation, and stiffening the bulkheads.” Because of the higher exothermal reaction of bio-based resins, he instructed the crew not to fill the buckets all the way. They used Sicomin’s InfuGreen 810, an epoxy the company says is produced with about 38% of carbon from plant origin contained in the molecule. According to the spec sheet, it was “specially formulated for resin transfer processes, such as injection or infusion.” (Sicomin claims to have the carbon content independently certified by the Carbon 14 method.) At 20°C (68°F), the air temperature in the shop was ideal for the job, and the vacuum pump was set to –1,000 mb. The crew prepared 80 kg (176 lbs) of resin, of which 60 kg–70 kg (132 lbs–154 lbs) were infused into the fabric and 15 kg (33 lbs) into the recycled PET core. Martin said, “Infusing the hull there’s more excitement, because there’s more riding on it than on small parts, which can be redone, if needed. We tried different resin systems, but it was a learning curve, e.g., [with] air inclusions.”

Composite PressDieter Loibner | Professional BoatBuilder Magazine

Greenboats upgraded this vintage 1960s press with digital controls to manage pressure, which can reach 6 bar, or kp/cm2 (87 lbs/sq in), and temperatures up to 200°C (392°F).

Meanwhile, others including Roman Urban, a composite technician who built rotor blades for giant wind turbines, were placing the first layers of flax fibers into the deck mold. This boat was not an exact copy of the first one. The cockpit was enlarged to include benches for sitting inside, a more comfortable and leisurely style of sailing. In addition to a 3-axis CNC machine in its own room to keep down dust pollution, Greenboats uses a vintage 1968 press to produce panels, bulkheads, and other flat composite structures. They upgraded this press with digital controls to manage pressure, which can reach 6 bar, or kp/cm² (87 lbs/sq in), and temperatures up to 200°C (392°F). The press is also employed for composite planks in the MB9, a 30 (9m) custom racer-cruiser commissioned for private use by Matthias Bröker, a designer at JV who worked on the popular Dehler 30 OD. “We made sheets in the press that consisted of flax, balsa, and larch wood,” Deimann said. “Those sheets were cut into battens we then scarfed into 10m [33] planks that conform nicely to the mold.”

Flax dry layupDieter Loibner | Professional BoatBuilder Magazine

Composite technician Roman Urban is layering flax fiber into the deck mold

Bröker said the unique feature of the MB9 is using flax fibers to lower the carbon footprint in construction. “We wanted to gain experience [with flax fibers], and Greenboats was almost the only option since they already built boats and parts from it.” They settled on strip-planking with balsa-cored battens that have wood on the outside and uni flax on the inside as the most economical method to build a one-off.

“Strength and E-module [of flax] are not as good as with glass, but the density is lower, so the [structure] is roughly 10% heavier,” Bröker said. Important mechanical properties for the fibers are longitudinal and compressive strength, while the core needs shear strength and density. “With core materials it’s not yet apparent if balsa remains a good alternative or if recycled foams are friendlier to the environment,” he said. Building with flax is, he added, “still too expensive for high-volume production, but the yards are paying close attention to position themselves for the future.”

Composite planks MB9Courtesy Matthias Bröker

The composite planks with flax, larch and balsa wood after being glued up in Greenboat’s press.

The bigger goal, Deimann said, is to start producing sheet goods made from natural fibers and bio-based resins to be sold to other builders at competitive rates. He hinted that he is working with a partner to develop a plant-based polyester resin. Moving into a supplier role is the next step for Greenboats, requiring different expertise and logistics than running a small custom shop with a diverse product portfolio including power and sailing skiffs, kite boards, standup paddleboards (SUPs), and flax components for racing yachts. Other projects include the camper shell for pickup trucks, the nacelle for a 180 (54.8m) wind turbine installation in The Netherlands, the body of a food truck, sleeping pods for camping, a bamboo bike, skateboards, a ROV, a GPS train tracker, and park benches.

Foodtruck body flaxCourtesy Greenboats

Greenboats has built a diverse portfolio of non-marine projects made of flax-fiber composite parts, including this food truck.

Data and Know-how

While Greenboats is not set up for industrial-scale production, the company is guarding the intellectual property it has accumulated over a decade-plus through building, testing, using and breaking stuff, matching materials and applications, finding the best processing techniques, and keeping a lid on cost. “Somehow you have to survive the price war, which is difficult if you start with material costs that exceed what others sell the final product for,” Deimann said. To convince the market, Greenboats also had to prove that flax isn’t just green but strong and safe as well. To that end, the company has been working with bionic scientists at the City University of Applied Sciences in Bremen and the Fraunhofer Gesellschaft (a global research organization). With traction and bending machines they test reference samples of composite panels and solid laminates made with flax fibers for breaking and shear strength. Evidence of this empirical research is displayed on the conference table in Deimann’s office in laminate samples with different core materials: twill with balsa or recycled-cork core, CSM with bio foam, biax with recycled PET core, and oak veneer alongside a stack of different core samples from Nomex honey­comb to resin-impregnated paper.

Core samplesDieter Loibner | Professional BoatBuilder Magazine

Various core samples with different skins were on display on Deimann’s conference table.

Because composite structures are only as good as the glue that holds the layers together, I asked Deimann about his preferred resins. “The ones with the highest bio content,” he replied. “Working in the press, I obviously use a different type of resin than for hand lamination or vacuum infusion. In the press we use a hot-curing product with approximately 80% of bio content with a long processing time that hardens quickly when temperature is increased.”

To see how Greenboats assesses the variables that determine material choices, I stopped at the desk of research and development engineer Paul Riesen. He is the keeper of the material database the company has built over the years. “Clients in general like performance, but not all want to go with the lowest price or the highest level of sustainability,” Riesen told me. To find the sweet spot, he plays with parameters imagined in a three-dimensional coordinate system with an axis each for price, performance, and sustainability. “Unless the customer demands the highest level, we don’t need to offer the most sustainable product,” Riesen said. “Sometimes it’s sufficient to take small steps. If sustainability is the top priority and performance ranks low, we might recommend building it from wood.”

MatrixCourtesy Greenboats

Greenboats’ sustainability-cost-performance matrix

The precise methods of construction are determined by materials data, finite element analysis, LCA, and the man-hours of required labor, tempered by hands-on experience and boatbuilding know-how. It’s not always necessary to go for maximum strength, Riesen said, pointing to the analysis and feedback from outsourced laminate and panel tests. “We make carbon fiber parts for keel and forestay attachments, for instance, but that’s less than 1% by weight of the entire boat, depending on application.” If material properties and indices are accurately documented, it’s a matter of running the numbers. Theoretically, those parts could also be made from flax laminate, he said, but if weight or emissions don’t pencil out due to higher epoxy resin consumption, what’s the point?

Growing Flax Business

On the topic of LCA: Greenboats is one of the pilot customers of MarineShift360, an LCA tool backed by 11th Hour Racing, a nonprofit concerned with sustainability and ocean health that sponsors an IMOCA racing team of the same name (see the sidebar). And because a rule in the IMOCA class now incentivizes building nonstructural parts from natural fibers with a weight credit as high as 100 kg (220 lbs)—1.25% of the displacement of approximately 8 tons—Greenboats seized the opportunity. The firm now produces flax-based components such as hatches, pipe berths, cockpit seats, electric panels, and floorboards for 11th Hour Racing and the German team of Boris Herrmann Racing, which is aligned with the Yacht Club of Monaco and supports the United Nations Sustainability Goals. Those parts require deft engineering, including mechanical analysis in Ansys, a simulation software that calculates stresses and deformations of the composite with its different materials and related properties.

IMOCA partsCourtesy Greenboats

Some hatches that Greenboats built for 11th Hour Racing Team’s IMOCA 60 and their use on board.

This relatively new business opportunity bringing visibility to the Green­boats brand is managed by Hendrik Plate, a young engineer with a Bachelor of Science in Engineering from Bremen University and a thesis on comparative simulation of the stability response for yacht rigs, and a master’s degree in Maritime Engineering Science from the University of Southampton, focusing on yachts and small craft, with a thesis on manufacturing and testing small-scale composite hydrofoils. He then worked as a technical specialist for World Sailing, helping with regulation and quality control of class equipment. “The French understand carbon prepregs very well, but they asked us about making flax components,” Plate told me. “We can build as strong as carbon fiber but a tad heavier, or we can build to the same weight, but then we are bit more flexible.”

While the parts might be small and nonstructural, they still require careful engineering. Across the hallway, Riesen opened the Ansys program on his screen and pulled up the statistical-mechanical analysis for an escape hatch installed on the stern of an IMOCA 60. The software calculates the areas of deformation and displays them in color code. The goal is to build these parts to withstand the same loads as carbon parts do, without increasing their weight by more than 20%. Because the IMOCA rule left room for interpretation of what counts as sustainable, Greenboats sticks to biologically grown materials.

Ansys analysisDieter Loibner | Professional BoatBuilder Magazine

Applying mechanical analysis in the Ansys software to the IMOCA escape hatch.

There is some irony in the practice of putting a few flax parts on boats that are designed to maximize performance and consequently must be built from high-modulus virgin carbon with its attendant waste and large carbon footprint. There is also the undeniable publicity effect of a Vendée Globe or Ocean Race that helps build awareness of the problem and possible solutions. “We network a lot,” Plate said. “Sailors claim an affinity to nature, love of the sport, and are interested in the environment but don’t have a clue how damaging the products are they are sailing on. So, we need to build confidence [in natural-fiber composites] and help change class rules that define what materials are legal to use in construction.”

Recycling Revisited

The idea that a Flax 27 could be recycled after 30 or 40 years and turned into garden compost is compelling, but Deimann remains skeptical. He claimed it’s possible to build a boat with 95% bio content, but he won’t do it until he can guarantee the materials’ life span. To him, longevity is a form of sustainability, so he asks, if it’s built to come apart easily, how long will its useful life be? “Recycling is the hot question and an important point, but it’s a tough topic,” he said. “We don’t deal with a single-use plastic cup but with boats that we build to last a long time.”

Deimann is concerned about breaking a thermoset matrix without excessive energy use, toxic solvents, or acids while protecting flax fibers from injury so they retain value for other applications. “What do you do with the fibers? If they are contaminated by acid, you have to clean them completely to make them adhere to resin again. I don’t see that path.” Carbon fibers are more robust than flax, so recycling them makes more sense to Deimann. However, as new technologies become available, he might change his view if they are practical and cost-efficient. One of them could be high-performance discontinuous fiber (HiPerDif), a technology that uses waterjets to align recycled chopped strand fiber in sufficient quality to be reused as feedstock for automated fiber placement, tape laying, or fused-filament fabrication in 3D printing. HiPerDif, developed by the University of Bristol in the U.K., could open new possibilities for the afterlife of various fibers processed with thermoplastics or thermoset resins. But for now, Deimann is content to say, “All right, we have a material that can be thermically recycled in CO2-neutral fashion and without residue while harvesting energy, which can be used for the manufacture of new products.”

When contemplating end-of-life options of flax fibers, the fundamental decision is about the resin, according to Paolo Dassi, marine and industry manager at flax fiber manufacturer BComp. The company makes and markets Amplitex, as either dry flax fiber or prepreg for thermoplastic and thermosetting applications. “It’s quite interesting to see how well the resin passes from the natural fiber after one cycle of washing out in a chemical bath,” Dassi said, referring to tests with thermoplastic resin. “If you do the same with the glass fiber, you see that some resin is still entrapped in the glass, and you need to do at least a couple of turns [in the bath]. I’ve seen some samples of Amplitex and Arkema Elium resin after the split, and it’s quite remarkable, because the fiber is completely neat, with no particles of plastic attached to it.” Could these fibers be reused? “Theoretically, yes,” Dassi replied, “but I’m not sure it’s viable from the practical point of view.”He added that once separated from the resin, a plant-based natural fiber like flax becomes biodegradable.

  • Flax fiber transparent
    Cork decking and the clear-coated flax fiber laminate of the Flax 27 daysailer

It’s different for composites made with thermosetting resins, where the industry still has to find an efficient and economical way of separating fibers from resin. “There are some ways of reusing the fibers, which means chopping them down and using them as a reinforcement in concrete or things like that,” Dassi said. “Because mechanical properties are knocked down by a factor of 60 to 70%, [the fibers] can’t operate in the same task that they were fulfilling before.” But even with incineration, Dassi added, construction with Amplitex produces substantially fewer emissions than glass or carbon parts, according to the company’s LCA. “This is why yards are now interested in using Ampli­tex for molds, because they typically are used for a short time but still use a lot of material.”

Joining the Party

While Greenboats forges ahead to produce more boats and sheet goods from flax for other boatbuilders and manufacturers in other fields, flax is making inroads in racing yachts and luxury yacht applications such as Baltic Yachts’ Café Racer 68 (see PBB No. 190, page 10). In North America, the trend is gathering momentum too, albeit behind closed doors. The Brunswick Corporation announced a partnership with Arkema “to develop a fully recyclable fiberglass boat” using the Elium thermoplastic resin in composite parts, a small step toward more sustainable boat construction. While large producers keep watching, the bulk of the R&D work, e.g., experimenting with materials and developing suitable construction methods, remains in the domain of small shops like Greenboats or Northern Light Composites in Italy. The latter outfit builds youth dinghies from flax fibers and Elium resin, and recently added a 7.69m (25) performance keelboat (see “Fiberglass Disposal, Part 2: Vanishing Acts,” PBB No. 190, page 46).

Leaving Bremen, I was impressed by the determination of the Greenboats crew, who are enthusiastically working to build better boats from more sustainable materials every day, even if the vision of reaching the lofty “net-zero” goal for emissions in an industrial process still seems utopian. Best to focus on progress, not perfection. What Deimann started a dozen years ago might have been perceived as a little kooky at the time, but he stuck with it, and as the impacts of climate change become too obvious to ignore, consumer sentiment is shifting in his favor. While switching to more sustainable materials and building practices alone won’t be enough to arrest climate change, it’s a necessary step if boatbuilding is to reduce its carbon footprint. And it also looks like a prudent hedge for the future of the business.

Dieter Loibner is editor-at-large of Professional BoatBuilder.

Sidebar: Measuring Impact with Life Cycle Assessment

In the name of optimization, humankind frantically collects and analyzes data about everything from voter attitudes to portfolio performance, step count, heart rate, and calorie burn. So, it’s no surprise that we extend this practice to quantifying the environmental impact of manufacturing processes in a life cycle assessment (LCA)—already a common practice in many industries—that could be coming to a boatyard near you.

© Amory Ross / 11th Hour Racing

Blazing the trail is the 11th Hour Racing Team, a professional sailing squad with ties to Newport, Rhode Island. It will compete in singlehanded and crewed ocean races on Mālama, a new IMOCA 60 racing yacht it built at CDK, a yard in Port la Forêt, France. The team analyzed the environmental impact of materials and services related to the construction with MarineShift360, the LCA tool developed for marine applications with the help of more than a dozen partner companies serving as beta testers and sources of input. The tool is backed by 11th Hour Racing, an organization that focuses on sustainability, education, and ocean health and also sponsors the IMOCA sailing team by the same name. The website states: 11th Hour Racing is part of the Eric and Wendy Schmidt Network including Schmidt Futures, Schmidt Marine Technology Partners, Schmidt Ocean Institute, The 11th Hour Project, The Schmidt Family Foundation, and Remain Nantucket.

IMOCA constructionLou-Kévin Roquais / 11th Hour Racing

11th Hour Racing Team’s new IMOCA under construction at the French CDK yard

The team published the findings and numerous recommendations in a 128-page report available for download. According to the report, the construction of a latest-generation IMOCA 60 produced 553 metric tons (1,220,000 lbs) of CO2 emissions, used 34 mt (75,000 lbs) of materials, generated 25 mt (55,000 lbs) of waste, and consumed 15,900,000 MJ of energy, the equivalent of 370 U.S. homes’ energy use for one year, and 7,500m³ (1,981,290 gal) of water. By comparison, the construction of Kairos, a vintage 2010 nonfoiling IMOCA, emitted an estimated 343 mt of CO2—less than two-thirds. “The overall design and build process has created more complicated deck, hull, mold, and components,” the report stated. “This has had an impact on material choices, energy used, and build time, which has more than doubled: 2010: 20,000-man hours; 2021: 40,000–45,000-man hours. It is in these last points that the team found the main reasons for such an increase in greenhouse gas emissions for an IMOCA build, and one of the key reasons for doing the comparison in the first place.”

Damian FoxallCourtesy 11th Hour Racing

Damian Foxall, 11th Hour
Racing Team’s sustainability

Because few yards are engaged in this sort of project, I asked Damian Foxall, 52, a veteran of six Volvo Ocean Race campaigns and now the sustainability program manager of 11th Hour Racing Team, what conventional boatbuilding outfits could do to reduce their environmental impact. “Embedding sustainability into a modern organization is no longer the kind of corporate social responsibility where at the end of the year the CEO would choose a couple of feel-good programs to tack on,” Foxall said and suggested five “buckets” of opportunity:

1. Sustainable Sourcing. “As a client, we have a lot of leverage to ask questions,” he said, “so we implemented a sustainable sourcing code and protocol across the full campaign. For every service provider, we have an internal system which tracks the process of engagement. We also sit down with them to understand their internal resources, philosophy, and practices, getting the okay to do an infrastructure audit in terms of material utilities, environmental safety, health, and safety standards.”

Foxall cited the energy audit at CDK. The yard uses electricity generated by renewable energy (as opposed to gas, coal, or nuclear power), which yields appreciable benefits in reducing the manufacturing carbon footprint. Selecting suppliers that offer renewable options, Foxall said, is a good option in mature energy markets such as the U.S. or Europe.

2. Avoid the Molds. The LCA numbers show that molds caused 32% of greenhouse gas emissions, followed by hull and deck with 30%, and appendages with 23.6%. Using molds for multiple builds or considering alternative construction techniques are viable solutions as is the choice of materials. “Removing 20% of nonstructural parts and replacing them with flax or recycled carbon fiber already equates a 17%–20% reduction [of emissions],” Foxall said, pointing to the new IMOCA rule that encourages the teams to build nonstructural parts from natural fibers for a weight credit.

Carbon and glass fibers last a long time but are energy hogs in production. Virgin carbon needs 355,000 MJ of energy per ton, according to the report, or 10 times more than fiberglass, which in turn requires about 10 times more energy than natural fibers like flax or hemp. “In terms of [virgin] versus recycled carbon fiber, we’re talking 5 to 20% of the footprint, depending on the modulus,” Foxall noted.

Prepreg cardboards© Lou-Kévin Roquais / 11th Hour Racing

The CDK yard returned cardboard packaging from prepregs to Gurit in Spain for recycling and reuse.

3. Circularity, Longevity, and Reuse: Mixing and matching materials is another path forward, but don’t discount a product’s long service life. “Around circularity, we need to think in terms of components and materials with end-of-life in mind,” Foxall said. “Some of the best materials and products we have today may not be the most environmentally [sound] upfront, but due to their longevity, they deliver a product that is unequalled.” For example, old Volvo 60s or ocean racing catamarans such as TAG/ENZA or PlayStation, built decades ago, still survive and find new uses today.

The report also includes a study of returning prepreg cardboards from the CDK to Gurit’s operation in Spain. A CO2-storage material, cardboard can be reused multiple times. Despite the emissions for the road transport, the calculation showed a reduction of carbon emissions and a welcome collateral benefit of savings in excess of €4,000 ($4,400).

4. Raison d’Etre: Answering the question about the purpose of boat ownership also can help with reducing the impact of boats on the environment. If leisure is the primary reason to go boating, why worry about speed? “We need a paradigm shift. We need to move beyond performance at all costs,” Foxall said. Pivoting from performance-centric innovation to more sustainable materials also needs rules like those requiring a strong one-design bent and clever engineering for a product that performs well, lasts a long time, and can be dismantled and recycled after the end of its service life. “It’s about finding other reasons to build, sell, and buy boats, and we need to do that in a conscious way,” Foxall said.

5. Rules and Legislation: How this might work is on display on European finger lakes (in Germany, Austria, and Switzerland) that teem with electric boats, not just because buyers ask for them, but because legislative incentives brought innovation and helped create the market. By that token, ditching record chases in favor of first-to-finish and one-design class rules that mandate the use of sustainable materials would rein in the costly and emissions-intensive arms race. High-end builders already incorporate flax in the material mix of new construction, not just for its desirable properties but also because of customer demand.

Power Ribs BComp© Ben Bireau / 11th Hour Racing

Another non-structural part of 11th Hour Racing’s IMOCA built with flax fibers and BComp’s Power Ribs to take advantage of a rule incentive.

Putting a threshold on carbon emissions and/or mandating LCA for future builds, as IMOCA does, are other options to increase sustainability in boatbuilding, Foxall said. Limiting CO2 emissions, he added, could be “part of the criteria builders and designers work with. Thinking about carbon accounts and greenhouse gas emissions, we need to put a number on that. We need to measure those impacts, understand what can be changed and be responsible for the outcome.”

Since the print issue went to press, the Marineshift 360 tool was launched. Click here to get free access to a starter version and to create the necessary account.