Fountaine-Pajot's Odysea 2030 Net Zero Carbon plan is bearing fruit and the company has just presented a new prototype, the Samana 59 Smart Electric x REXH2, a serial hybrid electric catamaran that abandons the diesel generator in favor of an EODEV fuel cell.

A sailboat ordered by Trade-Winds, a company organizing cabin cruises, which are satisfied with the disadvantages arising from the advantages of the propulsion of this boat.

The Samana 59 is a very large catamaran, equipped with an auxiliary electric propulsion system, whose electric motors (2x 50 kW) are powered by batteries (63 kWh) themselves recharged by an Eodev fuel cell, a diesel generator, photovoltaic panels (6 kWp) and wind turbine(s).

On this boat, the shipyard has added a hydrogen fuel cell to the diesel generator present on the Aura 51 Smart Electric.

The main interest lies in the fuel, dihydrogen, which can be produced from renewable energy, a fuel whose use in a fuel cell produces only pure water and heat. These cells have no moving parts and are known to be quiet and low vibration. Perfect for cabin cruising with a non-marine audience.

To power this battery, from Toyota (Mirai), one of the shareholders of EODEV, two tanks containing 15 kg of gas under high pressure have been installed. The battery produces 70 kWh and the 15 kg of hydrogen represent 3.5 hours of operation, or 250 kWh.

Fountaine-Pajot emphasizes several advantages of this configuration:

• The clean nature of the fuel, devoid of harmful effluents
• The silent operation of the fuel cell
• The electric-hydrogen autonomy provided at anchor (40 hours)
• And that in slow speed navigation (10 hours at 5 knots)

The choice of fuel and the EODEV fuel cell

There is a lot of talk about hydrogen fuel cells, but we must not lose sight of the fact that it still takes nearly 500 kWh to produce 200 kWh of dihydrogen. The origin of the energy used to produce dihydrogen is of great importance, or the "clean" advantage will evaporate. In addition, the batteries themselves are generators that suffer from an efficiency as low as that of diesel generators.

This fuel is difficult to store in large quantities on board, which explains the limited autonomy of this boat. Even if there is a lot of talk about hydrogen, the recharging of these tanks is done, for the moment, except in Marseille, the only national port equipped with an H2 station, by transhipment from trucks equipped with tanks.

While it does not seem impossible to move such a truck on the French Riviera or in one of the major Atlantic ports, it seems difficult to envisage the same thing from the navigation areas that these boats usually frequent (Caribbean, Adriatic, Aegean, Seychelles...). 

Trade-Winds, which will operate this boat in the Caribbean, will build its own H2 distribution station. This station could be supplied from Barbados, which is going to put into service a hydrolisation installation producing green dihydrogen, based on renewable energies.

Perhaps Tradewinds will also invest in a hydrogen manufacturing facility? We don't know at the time of writing.

A very low autonomy 

With ten short hours at 5 knots, and 63 kWh of LiFEPO4 batteries, the motor autonomy of the yacht during a one-week cruise takes a serious hit when compared to the hundreds of hours of autonomy of a diesel or hybrid diesel-electric catamaran.

But the fuel cell is also capable of powering the hotel services (electronics, air conditioning, cooking, hot water, pumps...) for 40 hours, the time of a weekend cruise...

To compensate for this very low autonomy, and to guarantee sufficient autonomy, the boat also carries a diesel generator and a dedicated diesel tank. A diesel generator which requires its own maintenance plan and which produces fumes.

A very specific use profile

Trade-Winds' sailing program in the Caribbean consists of short trips. The tour of Antigua, a cruise between St. Martin, Anguilla and St. Barts, or one in the protected archipelago of the BVI.  The navigation phases are short and the use of the engine can be very reduced.

This program is similar to the daytours, but without the night in port.

The small autonomy of the engine is then sufficient to cover the ten miles which separate, in the worst case, the boat from the safety of a shelter. 

The presence of a diesel generator highlights the weak point of this boat's autonomy.

Operated by Tradewinds, this sailboat will use its engines a few minutes per day, the time to leave or take an anchorage. If the navigation is then carried out under sail, the photovoltaic production (40-60 kW/day) and the hydrogeneration (5-20 kW?) should probably manage to recharge the propulsion batteries while ensuring the supply of the powerful consumers of the hotel services (the only air conditioning should consume between 8 and 10 kWh at full speed), without using too much the generator.

The battery is intended to provide additional autonomy to the batteries, whether for propulsion or for hotel services.

It is the very particular profile of this type of cruising, in protected areas and with a short range, that allows the main use of the battery rather than the generator.

The diesel generator is installed to keep the boat maneuverable in all cases, an imperative need for a professional operator.

The energy density of hydrogen as well as the difficulties posed by its supply considerably slow down its development on board pleasure boats, hitting them at the heart, namely their autonomy. 

The Energy Observer ship, which paved the way for these on-board hydrogen fuel cells, has a characteristic that is very difficult to transpose onto a pleasure catamaran: its ability to generate its own hydrogen, underway, in an autonomous way.

This is due to a huge photovoltaic power (34 kWp) and wind power (2 kW), capable of pumping, filtering, purifying, then hydrolysing and compressing sea water to make hydrogen. Also at stake is the energy sobriety of the Energy Observer's hotel services, two advantages that are very difficult to transpose on a prototype cruising catamaran.