The future of shipbuilding: a greener approach

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Sustainable materials and disruptive trends are needed to revolutionize the shipbuilding industry and make the future of shipbuilding greener. Rupert Holmes Reports

When enjoying a glorious day on the water, it’s easy to assume that sailing has to be one of the most sustainable activities on the planet. Yet in many ways the maritime industry is decades behind other sectors. Most new yachts use tons of virgin plastic that cannot be recycled – 250,000 tons of fiberglass are thrown away in Europe every year.

By contrast, more than 80% of end-of-life car materials have to be recycled since 2006. Perhaps the closest to this circular economy approach in shipbuilding is Vaan, a new Dutch brand, which has just launched its first 42-foot R4 aluminum model. . The hulls are made from over 60% recycled aluminum material and the entire boat is fully recyclable.

The Greenboats Flax 27 uses flax fibers woven under a transparent resin for its main structures.

Of course, composite structures, especially cored panels, are inherently more difficult to recycle than the stripped body of a car. A notable exception is the roto-molded hulls of small boats – RS Sailing, for example, uses a polyethylene material, which is easy to recycle, for this purpose.

Fortunately, manufacturers of raw materials such as resin and structural fibers are investing considerable sums in developing more sustainable options. Those who build boats using these development materials tend to be small, innovative companies.

Green Boats’s Flax 27 sailboat, for example, showcases structural flax fibers woven behind transparent resins, creating a unique appearance.

But Baltic Yachts have also used flax fibers in a number of projects, including for much of the recently launched 68-foot Baltic Café Racer layout.

The Baltic Café Racer is made from flax fibers

This use of natural materials and their association with bio-resins (usually made from by-products of sugar cane cultivation) is a big step forward. The carbon emissions required to produce the fibers are greatly reduced, while the resins are less harmful than standard polyester, vinyl esters or epoxies.

Volcanic potential

Basalt fiber also offers great potential: this volcanic rock can be crushed, then heated to very high temperatures and extruded through microscopic nozzles to form continuous structural fibers stronger than steel.

Despite the high temperatures involved, the process is straightforward. It uses a single raw material and only 5 kWh of electricity is needed to produce each kilogram of finished fiber, making it more durable than fiberglass.

It is the material of choice for Innovation Yachts based in Les Sables d’Olonne, which has already produced a 91-foot superyacht, an IMOCA 60-style vessel destined to break world records, and the first recyclable solar-electric boat. in the world built in composite materials. , the LBV35 catamaran.

Windelo, a new multihull shipyard in the south of France, has produced its first 50-foot and 54-foot catamarans using a composite sandwich of basalt fiber and PET foam, the latter made from recycled plastic bottles.

He says that compared to traditional fiberglass methods, it reduces carbon emissions by almost 50%. Neel Trimarans is also experimenting with many fibrous materials such as basalt and linen / linen combinations, bio-resins and PET cores, and is already incorporating these materials into the non-structural parts of its production yachts.

Use less materials

Green Boats founder Friedrich Deimann stresses that reducing the amount of material used is also an essential part of sustainable manufacturing. Green Boats helps the IMOCA 60 class produce the many small components that these boats use more sustainably.

The transom escape hatch on the new 11th Hour Racing boat, for example, is made of linen and bio-resin. More time spent on structural engineering means it meets the same structural criteria as carbon hatches, while being 20% ​​lighter. Likewise, the RS Aero dinghy weighs roughly the same as an Optimist, making it 50% lighter than many single-seaters its size.

11th hour of racing of the Fastnet Race 2021 Photo: James Tomlinson

Using half the amount of material halves the greenhouse gas emissions associated with raw materials, but can be difficult to achieve. Vacuum bagging has been used to optimize resin usage for over 25 years, to create stiffer, stronger, and lighter structures, but excess resin is effectively wasted once mixed and requires large amounts of quantities of single-use plastic.

For smaller components, Green Boats gets around this problem with a panel press that does the same job with significantly reduced waste. Dutch company Curveworks uses adaptive molds to create composite core structures that can be ‘stitched’ together into a larger shell.

The Arkema 4 Ocean 50 trimaran launched in 2020 uses recyclable Elium thermoplastic resin

Recycling

The fundamental problem with the resins currently used in shipbuilding is that they cannot be separated from the structural fibers, which makes them so difficult to recycle. Usually the only viable option is to grind the composite material to be used as a filler in the concrete.

The French company Arkema has developed a thermoplastic resin called Elium which can be used in the same way as conventional shipbuilding resins, but which can be fully recovered at end of life and used to produce a fresh material with properties identical to the resin. Virgin.

The process also makes it possible to reuse the recovered structural fibers, which is important for carbon fiber which requires a huge input of energy to create virgin fiber.

Another advantage of Elium is that unlike conventional shipbuilding resins, thermoplastics can be melted in a controlled manner, allowing the elements to be welded together.

Exo Technologies, based in the Isle of Man, has developed a patented material called DANU. It can also be recycled at the end of its life and the company describes it as a “circular composite material”. It is a combination of styrene-free resin and durable fibers that is stronger and lighter than fiberglass, but less brittle than carbon fiber. Ultimate Boats, a subsidiary of Exo Tech, is considering a 32-foot offshore racing boat that would use the DANU composite.

The Spirit 30 is the most sustainable Spirit Yacht to date: a combination of exemplary workmanship and environmentally friendly construction

Older technology is also worth mentioning in this context – cold-molded plank or strip construction where layers of wood are glued together with the grain at different angles, creating a light and stiff structure.

It has been a popular building method for low production yachts for almost 40 years and this is how Spirit Yachts continues to build. When combined with bio-resins, this can be a sustainable, low-carbon way to produce a boat.


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