The New Black
MOVE OVER, AEROSPACE AND AUTOMOTIVE DESIGNERS. YACHT-BUILDERS ARE LEADING THE WAY ON CARBON-FIBER INNOVATION.
Carbon fiber is light, strong and in vogue.
The distinctive black diamond weave of carbon fiber has crept into everyday items from watches and wallets to toilet seats and champagne bottles. But these primarily decorative functions belie the mechanical properties of carbon fiber, which, from exotic beginnings in aerospace, is fast becoming a mainstream yacht building material.
At first glance, the reasons are obvious. Compared with steel, aluminum or fiberglass, carbon composites are lighter, stronger and stiffer. Add their low thermal expansion and high corrosion and chemical resistance, and it’s no wonder that carbon fiber is widely regarded as a miracle material for boatbuilding.
“There have been two distinct developments in carbonfiber technology,” says Damon Roberts, engineering director at Britain’s Magma Structures, which built the self-supporting masts aboard the 289-foot (88-meter) Perini Navi Maltese Falcon, the 350-foot (106.7-meter) Oceanco Black Pearl and the 468-foot (142.8-meter) Nobiskrug sailing yacht A. “Firstly, where it improves on conventional materials, and secondly, where it makes completely new solutions possible. In the latter case, it is an enabling technology as opposed to just an incremental improvement.”
Sailing yacht A, designed by Philippe Starck with a radical rig by Dykstra Naval Architects, is technically a sail-assisted motoryacht with three unstayed, rotating, carbon-fiber masts. The main mast stands taller than London’s Big Ben above the waterline.
Metal spars that size cannot withstand loads that, under sail, may be more than double those on the wing of a Boeing Dreamliner. Instead, each mast was built in sections of epoxy pre-pregs—resin-impregnated, carbon-fiber cloth—in female molds, and then cured for three days. Even the Doyle sails are a mix of carbon and Technora, a synthetic polymer used for the parachute cords that kept a NASA Mars rover safe as it entered that planet’s atmosphere.
“There is much more understanding and acceptance of carbon composites since the days of Maltese Falcon,”
Roberts says. “In the early years, people didn’t appreciate that there are many different types of carbon fiber, and their performance differs. Nowadays, it is well known that you choose a high-strength or high-resistance fiber depending on the job, or indeed a blend of the two.”
With additional insights from software that can predict stresses, and from load sensors embedded into the structures, it is this greater understanding that has launched carbon fiber into mainstream boatbuilding. On the Baltic 175 (53.9-meter) Pink Gin, the world’s largest all-carbon sloop, the builder and composite consultants Gurit used finite element analysis to predict the curing of the topsides and hull, since even minimal deformation would have been disastrous when it came to joining the two together.
Just as there are different types of carbon fiber, there are different layup processes, from vacuum infusion and autoclaved pre-preg systems to carbon-reinforced thermoplastics that can be melted and fused. Understanding which is the most appropriate method to use is as important as selecting the right kind of carbon fiber in the first place.
“There is no ideal construction technology,” says Stefan Falcon, manager of the lamination department at Southern Wind Shipyard, whose semi-custom sailing yachts are built using infused sandwich techniques for the hull and pre-preg laminates for the deck. “The shipyard that chooses the right technology in the most efficient way is guaranteed a product of excellent quality suited to the type of use it has been designed for.”
For motoryachts, building in carbon fiber allows an increase in speed and range with less power. An extreme example is the 140-foot (42.6-meter) McConaughy Adastra. Launched in 2012, the power trimaran is a combination of carbon fiber, Nomex, E-glass and Kevlar. Powered by a single 1,000-horsepower Caterpillar engine, she burns just 26 gallons of fuel an hour at 17 knots, for a range of 4,000 nautical miles. At 10.5 knots, her range racks up to 10,000 nautical miles.
Unlike custom projects with budgets decided by their owners, production boats are built to strict financial margins. But even here carbon fiber is making inroads as the demand for lighter and faster boats pushes changes in materials and construction methods.
Azimut launched its Carbon Tech generation of yachts in 2015 with the Azimut 72, which has a carbon composite
superstructure atop an infused fiberglass hull. Carbon composite hardtops and superstructures have since been introduced across the builder’s range, the latest being the Azimut S7, which also has a carbon fiber swim platform.
“Because we can use less material with the same mechanical strength of traditional fiberglass, carbon composites provide a lower center of gravity for better dynamic stability, but also more interior volume on our flybridge and deckhouse models,” says Federico Lantero, Azimut brand manager.
Princess has teamed up with BAR technologies— whose design knowledge and technical skills stem from Land Rover BAR’s involvement in the America’s Cup— on a fully carbon 35-foot (10.6-meter) runabout. The Hinckley Company has been building its Picnic Boats from carbon and Kevlar for years, and recently introduced two 40-foot (12.2-meter) outboard models in a Sport Boat line with an updated infusion process.
“Earlier this year, we announced that we’re upgrading the vacuum-infused resin and using epoxy across our lineup, which brings increased strength and durability,” says Peter Saladino, chief marketing officer at Hinckley. “We’ve made substantial investments in
our facility in Maine to enable this approach. For the Sport Boats, we’re bringing this advanced boatbuilding approach to production performance boats.”
Still, there are downsides to carbon fiber. First, carbon fiber is costly. Prices have tumbled with increased consumption, but the material is still several times more expensive than aluminum—though it requires almost zero maintenance, so the material costs are allayed over time. Second, unlike fiberglass, it conducts electricity (Thomas Edison used carbonized cotton filaments in his early light bulbs) so electrical components must be carefully isolated.
Third, carbon fiber’s stiffness can be uncomfortable and “boomy” in certain sea states, requiring extra insulation to dampen hull noise that may add weight.
“If the objective is pure speed, then carbon fiber makes sense, but that’s not what Perini Navi is about,” says Fabrizio Sgariglia, sales director of the Italian builder of aluminum superyachts. “We build bluewater sailing yachts where the emphasis is on comfort as well as performance. It’s a question of whether you want a cruiser-racer or a racer-cruiser.”
One reason for higher costs is that carbon composites are difficult to recycle. Once they are fixed within a glue-like resin and cured at high temperature, the tough polymers have to be burned off or chemically dissolved
to reclaim the valuable carbon fibers. Boatbuilding is just one industry under pressure to adopt more sustainable work practices, and innovations such as recyclable epoxy resins may help. Studies are also underway to develop eco-friendly polymers that may be stronger than Kevlar or carbon fiber, perhaps using cellulose nanocrystals. Yacht owner Pierluigi Loro Piana used resin-impregnated linen fibers for the overhead and sole panels aboard his 130-foot (39.6-meter) Baltic My Song.
The future lies more in advanced manufacturing techniques than the materials themselves. Today’s robotic technology, for example, can replace the laborintensive process of laying up complex or one-off shapes in female molds. Magma Structures has already invested in automated processes for pre-preg tape laying that saves time and, potentially, money.
In the past, such technological advances originated in the aerospace or automotive sectors, but in the case of carbon composites, yachtbuilders are leading the way.
“In general, yachting has been able to push forward certain innovations that might be perceived as risky in other sectors,” Roberts says. “Partly that’s because we work in quite small teams on projects that require a multidisciplinary approach, but also because we’re lucky to have a few individual owners who are ready to move forward with the technology.”