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battery pack, sooner or later the system will need
an external energy source, and charging methods
and times are at present the only Achilles' heel of
this propulsion type.
In basins of the most environmentally-aware are-
as, such as Lake Como in Italy, a fair number of
charging stations have already been installed to
facilitate the shift to electricity; on Lake Garda,
not far from Lake Como, Repower has prepared
some automotive-type chargers with charging
power up to 22 kW in alternating current, a clear
sign of the tendency to find automotive-derived
solutions for electric-powered boats, both on bo-
ard and on the quay.
Recharging at sea
Of course things get complicated at sea, but the-
re are some viable solutions.
For a rough estimate, let's consider for example
a 38-foot sailboat (about 11.58 m) for cruise use,
with a 14 kW electric motor, suitable for a sailboat
that weighs about 7 tons.
At sea, the minimum power required is 2 kW per
displacement tonne for sailboats and 4 kW/t for
displacement powerboats; in lake areas, the po-
wer requirement is halved.
On top, a Focus 800 green: as the name implies
it is a green boat, i.e. powered by an electric
system, in this case manufactured by Oceanvolt
(the video is in Italian). Here above, a range of
motors made by the Austrian company Kräutler,
one of the leading manufacturers of marine elec-
tric motors. Here below, Bracciano lake, where
motorized sailing is forbidden.