Electric propulsion 10hp motor consumes 1000W/H at 4.3 knots. This performance data is based on a 12-foot aluminum boat on a calm lake water, with one person aboard. I do not know for a 25-foot cruising boat of 2500Kg, like the Django 770, it would perhaps consume 10% more, but lets just use that data.

In a single day your solar panel (140W, the largest a Django 770 can carry) would give you around 60A/12H at most, often less. It should be the double for your wind turbine (if able to turn at max speed during 24H). This most optimistic performance would give your battery roughly 2000W/day, in which case you will theoretically have 2 hours of autonomy (8.6 nautical miles).

Then again, considering the energy consumption of an autopilot and a computer, which need 3.5A/H (1000W/day), you would in reality only have 1 hour of autonomy (4.3 nautical miles). Another issue is the apparent wind, never really enough, and so a wind turbine will not give you more than 60A/24H. Talking about averages, the solar panel on most days can give you just 40A, which means you will have only 200W in excess for your electric propulsion, which equals to 12 minutes (1600 metres)!

On a weight-for-weight basis, the energy of petrol is much more powerful than the electric energy, which is also why the world can not sustain its actual consumption of energy only relying on fair and renewable energy, we have to change our life style! Living aboard and sailing is one way to do it, especially on a small boat!

Hope this helps. Good luck with everything! Kind regards, Christophe

Version (augmentée) en français dans la FAQ :
http://www.intothewind.fr/faq/

Quelques photos du tableau arrière dans cet article : Mise à l’eau !

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