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Discussion:
Is Electric Drive right for you?
1. Electric motoring does not produce noise or vibration.
Daysailing is a dream, you never have to turn the diesel or gasoline
motor on. Your sailing experience is peaceful and quiet from the
moment you get to the boat to the moment you return.
2. Batteries can be recharged from solar, wind, hydro, shorepower, or
generator. Generators can be sized to look after all necessary house
loads as well.
3. An electric motor can turn the propellor down to 30 rpm. A
diesel motor idling at 600 rpm through a 2:1 reduction gear has a
minimum speed of 300 rpm. The sailor has far greater control over
the sailboat during docking and maneuvering.
4. An electric motor has more power than its comparable diesel
motor for faster acceleration and braking to avoid collisions.
Electric motors do not need to be started prior to use and propulsion
power is always available on demand. Electric motors can produce
enormous amounts of power, 2 or more times their continuous ratings
for intermittent use.
6. Motor sailing with an electric motor is quiet and pollution
free. Just a small amount of power on the propeller creates
apparent wind on the sailplan, allowing a sailboat to sail through
low wind conditions.
7. Diesel DC gensets can be located out of living spaces and can
be mounted in locations that help balance the boat.
8. Electric sailboats can use their motors for maneuvering under
sail. Changing course in heavy wind conditions can be helped with
the addition of electric power. Tacking under power helps
eliminate becoming stuck in irons.
9. The large battery bank can be used for house loads. The large
battery bank allows for minimization of genset run time on
anchorage. Depending on the battery size, an electric boat could spend a
week or more on anchorage without running the genset.
10. Electric motors are more reliable than diesel motors.
Electric installations are built of several different components, all
of which a boat owner can keep spares and easily change if necessary.
11. Diesel DC gensets always work at peak operating efficiency and
specific rpms. They are always loaded properly and consequently the
diesel engines on a DC genset last longer and are more reliable than
a diesel propulsion motor.
12. The alternator on a typical diesel motor uses from 2 to 5
horsepower. This could be between 5 to 25% of the engines rated
output. Alternators are about 50% efficient. Recharging batteries
at anchorage is therefore 2.5 to 12 percent efficient. By contrast
a diesel DC genset by Polar Power is 85% efficient. Keep in mind
that inefficiency is heat, so a very inefficient system is a large
producer of heat – the last thing you want on your boat unless
cruising the polar ice caps.
13. Diesel Electric drives are more expensive than traditional
diesel.
14. Traditional Diesel has a longer motor only range than an
diesel electric if motoring at the most efficient rpm of the diesel.
COST COMPARISON
1. ATW electric drives are less money and easier to install
than diesel motors.
2. Diesel Electric Drives cost more money than a
traditional diesel motor.
3. A Diesel Electric Drive with an inverter is comparable
in cost to traditional diesel motor with an AC diesel genset.
CONCLUSION
If you are a Daysailor, an ell-electric drive
is better in every regard and is now less expensive than a diesel.
If you are a Sailor, and sail because you like
the zen of it all, then an all-electric drive is right for you.
The higher initial investment for Cruisers
buying diesel electric starts paying off right away with convenience,
cleanliness, reliability, and enhanced quality of life aboard.
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Above the Waterline
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