Dual solar sailing projects eye circumnavigation

Anne L. Fischer, Senior Editor, anne.fischer@laurin.com

Sailing under wind power has always been green, but two solar boat projects bring the concept to a new level. Both boats are catamarans and plan to circle the globe powered solely by the sun.

Currently under construction in Kiel, Germany, is a double-hulled boat being built by PlanetSolar, complete with 38,000 monocrystalline polysilicon solar cells that will cover more than 470 sq m on the deck. The cells, from SunPower Corp. of San Jose, Calif., will have an efficiency of 22 percent. The boat will be 30 m long, will weigh 10 tons and will have a 15-m beam.

The PlanetSolar catamaran will have 470 sq m of solar cells on deck to power it around the world next year.

The goal is to circle the world in 2010 in 140 days at an average speed of 8 knots. The boat will carry two sailors for the voyage but will be able to accommodate as many as 50 visitors who may tour the boat at each stop.

In conjunction with the boat project, a PlanetSolar village was opened in Yverdon-les-Bains, Switzerland, where visitors can see demonstrations of renewable energy sources as well as learn about the solar boat. The project is being led by Raphael Domjan, who founded Planet-Solar and who will skipper the boat. Financing is provided by Rivendell Holding AG of Zug, Switzerland, a firm that invests in renewable energy.

In another project, a boat called the Solar Circumnavigator is being built under the guidance of Anthony Howarth, a designer/sailor who had the idea more than 20 years ago. At that time, however, he could find little backing. But, today, financing is a different story, as the undertaking recently received funding from the Peoples Projects Foundation, a nonprofit organization based in the Netherlands that is dedicated to advancing the use of alternative energies. If all goes as planned, the boat will embark on two voyages in 2011.

The Solar Circumnavigator’s photovoltaic cells will have an efficiency of 30 percent, and their ability to self-orient toward the sun will make them, on average, from 25 to 50 percent more efficient than a fixed solar array. DC motors will be driven directly by the solar energy, excess daylight energy being accumulated in lithium ion batteries to maintain speed throughout the night. Two large-diameter, slow-speed cruising propellers have been designed for sustainable speeds of ~12 knots; they are effective between 8 and 16 knots. A second pair of propellers can be lowered into the water for bursts of higher speeds, and a third pair can be lowered for slow-speed maneuvering in ports and while docking.

The 20-m catamaran, with a 10-m beam, will have a maximum speed of more than 30 knots and will be capable of carrying up to 12 people for short cruises. Also onboard will be a fully solar-powered dinghy as well as two solar-powered vehicles for use in ports of call.

During the first 100-day trip around the world, the crew members hope to demonstrate the potential of solar power in transport and how it might be used for shipping. They also will be making a feature film of the voyage to promote the important role that solar plays in the mix of energy generation.