Perpetual energy is impossible. Here on Earth we know our energy-giver, the Sun, will blaze out in about five billion years. But we all get by on shorter lifetimes than that, so a form of transport that can be powered by sunlight and nothing else sure looks miraculous to us.

Singapore-based solar-powered yacht-maker Azura Marine brought the dream of unlimited propulsion a little closer when it tested its Aquanima 40 vessel in the waters near Bali, Indonesia, recently.

During a four-hour sea trial, the Solar Eclipse achieved a maximum speed of more than 8.5 knots and was able to cruise continuously at 4.5 knots using less than 2kW of electricity an hour while producing more than 8kW from her 30 solar panels.

At the end of its jaunt, this meant the yacht returned to her mooring with 100% battery charge after conducting several high-speed tests and drawing charge to power navigation and domestic systems.

“The fact that the Aquanima 40, even in full spec version and fully loaded with fresh water and dive gear onboard, is able to achieve this energetic balance is the holy grail of true solar-powered vessels,” said Azura Marine CEO Julien Mélot. “Even I was surprised that we were able to immediately achieve cruise speed with such minimal power consumption.”

Quiet on the calm sea

The 13-metre, 10-tonne vessel is topped by a 10kW solar roof and carries a 60kWh battery bank. The company claims the generation and storage aboard the vessel allow unlimited continuous range, “day and night”, with no need for shore plug in or fossil fuels. 

“Customers are wanting something different and to ditch fossil fuels completely,” said commercial director Simon Turner. “These people are not interested in thrashing around at 30 knots but more in having a joyous, silent, cruising experience safe in the knowledge that they are not harming our oceans and marine life, let alone not incurring a single cent of fuel cost.”

The Aquanima hulls were developed at Harbin Engineering University, China, with research overseen by lecturer and Azura Marine cofounder Xueqian Zhou. “The new trend for modern catamarans is to move away from inefficient boxy floating apartments towards performance yachts that are far more enjoyable to use and this meets our requirement for minimal resistance through the water for an energy efficient vessel,” said Professor Zhou.

Customers can increase speed and reduce energy consumption by opting for more powerful e-motors and a mast and sails package. All yachts carry an automatically engaged emergency generator.