Anyone who has visited La Rochelle over the past 25 years will have seen the electric ferries with huge solar arrays that transport locals and visitors alike between the town centre and the giant Port des Minimes marina on the opposite shore.

These systems were created by local company Alternative Energies, which has expanded over the years and has now fitted its equipment to almost 100 mostly commercial vessels that have collectively notched up a million hours of operation. The firm is now part of the Fountaine-Pajot/Dufour group and a joint offshoot named JOOOL has developed a fully integrated, turnkey hybrid system aimed at a wide range of 35-65ft monohulls and multihulls.

It encompasses all aspects of the management, storage and production of energy on board, covering both propulsion and domestic systems, including refrigeration, cooking and, where fitted, air conditioning. It can also supply the power for electric tender motors, eliminating the need to carry different fuels.

JOOOL Hybrid energy and propulsion system overview

• What is it? Complete turn-key hybrid system for cruising yachts, encompassing propulsion, high capacity batteries and multiple charging sources, including range-extending generators
• Who’s it for? Those seeking a yacht with quiet, efficient operation and a huge battery bank powering on board appliances and creature comforts, combined with long-range autonomy

JOOOL’s turnkey hybrid power and propulsion system is aimed at 35-65ft yachts

Power generation

As with the solar-powered ferries, a key aspect is that it’s possible to generate significant amounts of power on board via large solar arrays, plus hydrogeneration when sailing. This is significant as it reduces dependency on diesel generators for powering the considerable domestic loads of today’s yachts. These multiple charge sources also represent built-in redundancy – if one element fails it’s still possible to keep the batteries topped up.

A further advantage is that the electric propulsion is far quieter than a diesel engine, with less vibration, and can be used for an ultra-efficient extra push when motor-sailing.

A soundproofed diesel generator offers back-up for domestic power, for instance when at anchor in cloudy weather for several days, and extends motoring range. There’s also a powerful shorepower charger system for use in port.

Solar panel-covered lounge deck of a new Fountaine Pajot 41 catamaran

Integrated system

At the heart of the system is what JOOOL calls its OneBox. This compact energy management and conversion unit integrates all energy sources and outputs, including solar, wind, hydrogeneration, gensets, and shore power.

Although the JOOOL Hybrid system has only just been formally announced, the advent of the Smart Electric version of the Fountaine-Pajot Aura 51 in 2022 marked an important milestone. I also sailed a Dufour 470 from this period fitted with a pre-production system. A stand-out aspect is that massively heavy-duty and cumbersome wiring isn’t needed, nor is a complex water cooling system for the motor.

The key to this lies in the relatively high DC voltages used, which exponentially reduce the electrical current needed to drive the motor. Reliability and safety are of course key requirements for such systems. JOOOL can point to the long and successful track record Alternative Energies has in commercial passenger vessels.

JOOOL will operate as a separate business, supplying hybrid propulsion and energy systems to boatbuilders around the world. Leopard is an early client, and exhibited its new 46ft catamaran with twin 25kW POD motors, a 54kWh battery bank and32kW diesel generator at this year’s International Multihull Show in La Grande Motte.

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