ENGINES GOING GREEN
BY JOHN ADEY
RUN SILENT, RUN GREEN
The electric/hybrid boat market is heating up with new models as
well as repower options. Should your next boat be a hybrid?
The Greenline Hybrid is equipped with both a VW diesel and electric motor, so it can run silently up to 6 knots, or up to 15 knots on diesel power.
THE PHRASES ARE FAMILIAR NOW, and promising: “green, smaller carbon footprint, hybrid,” and so on. We’ve seen the growing success of hybrids in the automotive market, and we’re starting to see the same trend when it comes to boats. So what are the things a potential buyer should know? Could
a hybrid fit the way you boat?
The concept of hybrids at sea isn’t new. WWI submarines used a diesel engine by night
to charge batteries for electric propulsion underwater by day. Hybrid means anything that
supplements a traditional combustion engine, be it gasoline or diesel. The supplement can
be done in one of two ways: parallel or serial. Let’s look at the distinctions:
SERIAL HYBRID — The prime mover is an electric motor supplied by a substantial
battery bank of any type. A generator is optimized purely to charge the battery bank. The
generator control can be automatic; starting and operating based on need without the captain’s intervention, or manual where the captain decides when he or she would like to begin
the charge cycle. These installations typically also include provisions for charging with shore,
solar, or wind power.
PARALLEL HYBRID — The prime mover can be a combustion engine or an electric
motor. Both drive the same prop shaft(s). Generally the installation will look like a traditional
combustion engine but include an electric
motor component between the engine and
transmission. The key to this technology is
the clutch system. You may be able to shift
on the fly, seamlessly changing from com-
bustion to electric with
the touch of a button
— though some require
the engine to come to a
complete stop before switching to electric.
Charging batteries is carried out by the
engine through advanced controllers and in
some installations is supplemented by large
WHERE DO I START?
Let’s imagine for a moment how the move to
a hybrid boat would change your approach
to boating. Consider a typical cruising day,
leaving the dock and navigating through the
mooring field and buoyed channels under
electric power only, silently, without having
to yell over the drone of the engines. Once
out in the open, you’d switch to the combustion engine for higher speeds and battery
recharging. Arrival at your anchorage allows
you to switch to electric to find the perfect
spot and set the hook. The evening never
requires the use of the generator, because the
combustion engine charges the battery bank
during the trip. In the morning, depending on the battery bank and usage, electric
UNLIKE CARS, WHERE THE HYBRID VERSION CAN COST UP TO 50% MORE THAN THE BASE MODEL, UPGRADING
TO AN ELECTRIC MOTOR ON A HUNTER 36 ONLY ADDS AROUND 2% TO THE COST OF THE BOAT.