The new Fountaine-Pajot Aura 51 catamaran is certainly a beautiful boat. Sleek, relatively low on the water, with generous windows and a high-performance rig. It is also a comfortable and easy-to-live-with boat.

The Smart Electric version that we were able to try out adds a hybrid electric motor that allows the boat to be sailed under engine in calm conditions, a configuration that greatly limits the boat's carbon emissions.

The Aura 51, volume, space and comfort

With a lenght of 16 metres and over 8 metres wide, the Aura 51 is a large boat. The five-cabin version, which we tried out, has a very large aft cabin on the port side, with an armchair and a large dressing room, its own shower room with separate WC and an acceptable forward cabin with an island bed and shower room.

The starboard hull has three cabins. Two are accessible from the nacelle and each has an island bed and en suite shower room, while the last has separate access from the aft cockpit.

The nacelle has a vast galley with a central island to port and a saloon with a coffee table to starboard. There is no chart table, but two navigation screens, one in the nacelle and one on the flying bridge.

The aft cockpit has a large table, which can be folded out to seat two additional guests on the aft cockpit bench. On either side of the table are two loungers, ideal for siestas.

At the stern, a practical Tenderlift makes launching the serious tender supplied with the boat ultra-easy. Raising the tender is a breeze.

A truly powerful sailboat

Once you're at the helm, you'll be delighted to see that the boom is always at an accessible height from the flying bridge. With a 95m2 mainsail, it's great to be able to act directly on it when reefing or lowering the sail, all from the flyingbridge.

The gaff mainsail and the beautiful matching genoa (59m2) deliver a definite power under sail to this boat, which reaches 10 knots effortlessly in 20 knots of wind. Not bad for a 25-tonne loaded yacht! The two electric winches are welcome to help with manoeuvring, as is the presence of a strong crew member to help hoist the sails from the foot of the mast.

The boat is fitted with three reefs, the first of which is automatic, and all the controls are positioned in front of the helmsman on the flexible photovoltaic panels covering the coachroof.

At the helm, even if you don't feel like you're at the helm, the feeling of power is there, especially in the chop, where the boat cuts its course with sovereignty.

The roof itself houses a large U-shaped flybridge saloon where everyone can find their place.

Aura 51, powered by Smart Electric

The 75 HP diesel engines of the base model and its 11 kW generator have been replaced on this boat by two 400 V electric propulsion systems, each consisting of an outboard pod motor (26 kW), an LFP lithium battery and a set of power electronics. These two systems are independent, as on a conventional catamaran, and the boat can rely on one if the other should fail.

In port, the batteries of these two systems (2x27 kWh) will be able to draw their energy from the shore chargers, which can be recharged overnight. When sailing, stopped electric motors are driven by the water and, when set in motion, they produce current. This hydro generation, which can be improved, delivers around 1 kWh per hour of sailing. When the boat hydro-generates, it produces a perceptible noise, but it's bearable because you know you're putting up with it for the right reason, to generate power...

The most powerful charging system on board is a 32 kW generator, which starts automatically when the SOC (state of charge) of the batteries falls below 80% and is capable of recharging the batteries in a few hours. More importantly, this generator is capable of keeping the yacht running at a speed of between 6 and 7 knots, even if the batteries are flat, until the 1000 litres of diesel run out.

When the boat is running on full batteries, it has a range of three to four hours at around five knots. Faced with wind and waves, the power required to maintain engine speed increases while range decreases.

With the electric motor alone, a slight noise is still perceptible, but it's nothing like the racket orchestrated by two diesels in operation. It's particularly noticeable inside the rear cabins.

When the generator starts up, it is fitted with an insulating cocoon and placed in a soundproof hold, and is remarkably discreet. It makes no more noise than the smaller generators we're used to.

The management and understanding of the displays, apart from a few display and conversion bugs, works well and makes it easy to understand how the yacht's energy system works.

The batteries of the propulsion systems can be pooled with the (too) small service batteries to recharge them, which ensures that you can tackle the night with full service batteries.

Finally, in terms of fuel consumption, replacing the two diesel propulsion engines and the service generator with a single powerful generator drastically reduces fuel consumption by more than 50%. On the scale of a cruise, that's 100 to 200 litres of diesel saved, and just as many fewer emissions and particles. Over the life of the boat, this means tens of thousands of litres of diesel will not be consumed.