NAS SAILING CENTER PUNAT - #sail #learn #enjoy

Electric hybrid sailing catamaran Independent I – the brain of the electric propulsion system

Unlike a classic diesel propulsion system, an electric hybrid propulsion system is made of more components. The engine or engines, a battery, in case of a hybrid, a generator, usually a photovoltaic array, a charger. Then as an additional component, non-essential for the propulsion, is the inverter. All these systems need to be set up correctly and monitored. As our readers will probably know, one of the most esteemed world brands for electrical direct current products and inverters is Victron. We have chosen this system because of it quality, but also wide adoption and modularity. At the center of this multiple devices is the Cerbo GX, a small, dedicated computer that serves as the communication centre. The Cerbo GX has a touch screen, situated at the skippers table, that shows all the relevant parameters.

Through the screen you will be able to monitor the battery state of charge (SOC) expressed in percentages and kwH, the electricity consumption, the power generated by the solar panels, the diesel (generator) and water tank level.
The system will sound an alarm in case of some anomalies in the system, such as low SOC (state of charge), overvoltage and so on and alert us through an online platform.
The system is permanently connected to the Internet when in range of a mobile network. Four your charter trips from Punat, you will have full mobile data coverage in the entire navigation area.
The Cerbo GX has also control over the generator start-stop function, depending on battery SOC, but also on the momentary power consumption. We will have a separate blog on the generator function, when and how it is activated, whether automatically or manually.
The Cerbo GX also monitors the battery temperature, turning on a fan in the battery room to cool them if necessary.
At check-in the, the batteries will be fully charged and the tanks will be full. As in case of diesel boats, always check the state of the tanks and in our case of the battery SOC.
Follow us next week with some information on the batteries.

Electric Hybrid Catamaran INDEPENDENT I – Technical characteristics

Our new electric hybrid sailing catamaran INDEPENDENT I is tailored to assure the most appropriate characteristics for the charter guest. Follow this blog to learn more about its characteristics and the conversion process.

INDEPENDENT I will have two 10.9 kW underwater pod engines each. While fully loaded, the Lagoon 400 S2 will displace approximately 12.5 tons of water, but the engines are sufficient for boats up to 16 tons of displacement. This is due to their high torque of 56 Nm, available from 0 rpm. The engines work at 48V.

The catamaran is equipped with a 44 kWh 48 V battery bank or 920 Ah. The batteries are based on the ultra-safe LiFePo4 technology. While on shore power, on the most common 16 A marina plug, you will be able to charge from 10% to 100% in approximately 11 hours, or the time you usually spend in the marina or on berth during an overnight stay from 8:00 PM to 7:00 AM. Of course, at check-in, the catamaran will be waiting for you to be fully charged.

You will have at your disposal a powerful 13 kW DC diesel generator. The generator is situated in the engine compartment, carefully isolated. The generator is significantly more silent than the engine it replaces and transfers significantly less vibrations to the hull. We opted for DC generator, the most appropriate option for hybrid propulsion, since the generator is directly feeding the batteries with DC current.

We shall install 2.5 kW of solar panels. INDEPENDENT I will have an exceptionally powerful solar array situated above the dinghy and partly on the roof. The inox frame above the dinghy and the wide roof will allow for the installation of hard solar panels. Hard panels are much more efficient and long-lasting than flexible ones. On some spots, as parts of the roof, we will have installed flexible panels, that can be walked on if needed.

For charging the batteries and feeding the AC system on board, the boat is equipped with a 48/10000 Multiplus II Victron inverter/charger. The Multi can charge up to app 7.2 kW or 140 A when you are on a 32 A shore plug. On the other hand, it can provide up to 10 kW for the AC system, which is more than most apartments have.

The 12 V system has a powerful and long lasting 400 Ah LiFePo4 battery bank.

Follow us next week to learn more about the Venus OS and Cerbo GX, the Victron operating system and computer that coordinate the work of the electric system.

INDEPENDENT I – The new ELECTRIC HYBRID SAILING CATAMARAN at NAS Sailing Center in Punat, Croatia

NAS Sailing Center is pleased to announce a new entry in our fleet for charter season 2025, a Lagoon 400 S2 electric hybrid sailing catamaran.

Together with our new electric hybrid sailing catamaran we also announce this blog. Through this blog you will be able to follow the conversion of the boat to electric hybrid propulsion, learn the technical aspects of the boat, get to know all the advantages of maritime electric propulsion, understand how to use the new engines and electric system and many other things about this topic.

We hope you will join our community of enthusiasts, who understand that sailing, in its essence, is a bond between men and nature. If sail we must, it is our responsibility and duty to do it with the utmost respect for the environment.

The Green transition is a necessity. However, if we are talking about sailing, it is also a pleasure, due to the many advantages that marine electric propulsion offers to recreational sailors.

Take as an example the first big, immediately noticeable, difference between a diesel and an electric engine – there is no noise. Imagine a pristine summer morning. You get up a little earlier than your kids and friends on board. You take a brief swim in the crystal-clear sea. HHHHave your coffee and it is time go, maybe to catch the morning breeze. Instead of waking everybody up by starting two smoky gargling diesels, you simply give a little push to the throttle and glide in complete silence out of the anchorage. When you first try it, until you get used to it, it feels almost surreal. You only hear the water gently flowing on the hull. There are no vibrations reverberating through the saloon, no cups rattling on the table. Your friends, who are on their first sailing trip, sleeping in the back cabin, don’t have to cover their heads with pillows. They just enjoy the gentle lull of small morning waves and the sea flowing under the boat.

Silence is not important only for people, it is also important for fish and other marine creatures. Have you ever tried diving even a little, to hear the noisy hum of an engine that seemed right behind your head, just to surface and see a boat in the distance. Sound propagates through water more than four times faster than through air? What is our pleasure in summer, for the underwater world is a cacophony of hundreds of different noises. If we can help reduce that, we have done something good both for ourselves and for the environment.