Turanor Planet Solar, an all-solar powered ship, will navigate out of Mediterranean Sea and into the vast Atlantic Ocean later today, just over a week after it embarked on a journey around the globe.

The boat, which set sail Sept. 27 from Monaco, is a multi-hulled vessel almost 100 feet long. Covered in almost 5,800 square feet of photovoltaic solar panels, it’s the largest solar-powered boat ever built.

The Turanor crew’s goal is to circumnavigate the globe in about eight months, maintaining a speed of 7.5 knots while using only the sun for power.

After a week at sea, the crew say the journey is going well. Patrick Marchesseau, the boat’s captain and Raphael Domjam, Planet Solar project founder, have been keeping a brief daily journal of their adventure on their web site planetsolar.org.

They’ve been watching the dolphins and admiring the sea life this last week. Domjam also broke a tooth on a dive and has had to fly home to Switzerland to get it fixed. But even with that, there have been no major surprises.

“Since we have expected the project to be a real expedition right from the beginning, we do not speak about ‘unexpected challenges,’” Marchesseau wrote in an e-mail to Clean Energy Authority.

Marchesseau is a French boat captain with decades of experience at the helms of a number of different kinds of sea vessels. He’s sailed the world. But this is the first time he’s navigated a solar ship, he wrote.

“The difference between the solar ship Turanor Planetsolar and a regular motor vessel is in the energy management, of course,” Marchesseau wrote. “With a motor vessel, you know how many nautical miles you can sail through according to your bunker capacity. With a solar boat like Turanor Planetsolar, we have approximately up to three days of energy available from our batteries. So we have to adapt our consumption, which means our speed, according to the weather, in order to always maintain a minimum level of energy for safety reasons.”

The crew’s mission is to show the world the existing solar technology is viable and functional, Domjam wrote.

He learned through working with solar that it was a simpler solution than people believed and that it was accessible.

“I strongly felt the wish to find something in order to demonstrate that solutions do exist, and that solar energy in general is functional,” Domjam wrote. “I was thinking of a world tour.”

He considered various types of mobile technologies—cars, planes. Others were already working on such tours.

“I thought that a boat was an excellent conveyance to get into the heart of cities, to get close to people, to take politicians and industrials on board and let them experience solar energy,” Domjam wrote. “At the same time, with a boat, we could demonstrate the functionality and economic efficiency today, and not in some hypothetical future.”

Follow the boats progress at planetsolar.org

Pictured: Turano departs Monaco on Sept. 27.