Solar Paneled Catamaran Makes Light with Composites

The center hull shell is made of a composite sandwich, allowing the solar-powered catamaran to remain light-weight despite its 825 panels.

After a bit of pomp and circumstance, the Tûranor Planet Solar (an Elvish name meaning “power of the sun” in the Lord of the Ring trilogy by J.R.R. Tolkien) was lifted out into the world on its first adventure. But what makes this boat so special? Sure, you may notice the usual carbon-sandwich design within the 30-meter long catamaran (the largest ever built), but for the truly unique you’ll need to look a bit higher. This high performance catamaran’s deck is covered with photovoltaic panels, 825 in all, giving it nearly 94,000 kilowatts (KW) of power.

In 2006, Raphaël Domjan, the project leader and skipper, came up with the idea to circumnavigate the globe in a boat powered solely on solar energy. Domjan recruited German-based Knierim Yachtbau to aid in his concept due to the company’s experience with individual high tech yacht construction. “In the design, we started with a blank slate,” says Yactbau’s CEO Steffan Muller. “We soon realized that in order to give the boat enough surface space to accommodate the solar panels, the catamaran most likely needed to be a multihull design. A multihull would provide a large surface area and create less drag through the water.” However, the team needed help determining if the best multihull would be a catamaran or a trimaran. After speaking with various designers, they chose Craig Loomes Design, based in Auckland, New Zealand, to design a wave-piercing catamaran.

From the beginning, Muller says it was clear that the boat needed to be as light as possible in order to effectively use the energy generated from the panels. “On the other hand, however, we knew it needed to be strong enough to survive any storm or large waves that occur in the ocean. The only solution was to implement composite technology using a carbon fiber sandwich,” he says. “We ran various computer simulations and predictive programming to identify how each section of the boat should be constructed.” Eventually the team created tank testing with a 1:20 scale model for safety requirements, which was monitored by Germanischer Lloyd (GL).Manuevers in a catamaran of this kind had never been done, so the team needed to understand the behavior of the materials in different conditions to know how much power is needed to run at various speeds. This process took approximately nine months then moved on to another 16 months in manufacturing.

The hull itself is made from a light carbon-sandwich design and epoxy resin with structural foam of various densities to increase strength and stiffness of the structure at minimum weight. “Composites play an important role in this vessel. We believe this catamaran could not have been possible if it were to be built out of any other material, such as aluminum or steel,” says Muller. “These particular composite materials were chosen because we felt they provide the best relation between weight and durability and stiffness. But in some crucial areas like the beams connecting the demi hulls and the main hull, which provides the connection between the main hull and the swimmers, we decided to use plain carbon fiber layers—not sandwich—because the impact given by waves can be so strong.”

Despite their triumphant completion of a strong catamaran, Muller admits it could easily be dead in the water. “One fallback to a solar-powered catamaran is power source. The battery power is limited to three days or so. If the sun doesn’t shine for a long period of time, you’re out of luck. Therefore one of the biggest challenges will be to find a route with enough sunshine along with favorable winds and currents that will bring it back to its Mediterranean starting point,” he says.