Boat International - February 2016

Illustration – Patrick Hruby

ON BOARD

engine

room

Save fuel, money and the planet! Hybrid ’s
rallying cry is trending, with more and more
yacht builders ofering blended propulsion
options. Hybrid power isn’t new, of course.
Nearly 20 years ago, Lürssen gave us the
Jon Bannenberg-designed 96.25 metre Limitless
with diesel electric power, and the validity
of hybrid was cemented when RINA awarded
the new Hybrid Propulsion class notation
to Palumbo’s Columbus 40S in 2013. But are
all hybrid superyachts created equal?

“Hybrid itself doesn’t mean that much,” says
Ronno Schouten, design manager of Feadship’s
De Voogt Naval Architects. “The definition
is basically ‘a thing made by combining two
elements’. It’s become a trendy word that
everyone uses.” The yard took hybrid to the
next level with the 2015 launch of 83.5 metre
Savannah, featuring its Breathe propulsion
system. Here, a single medium-speed
diesel engine drives a single prop via
a gearbox, and aft of this is a large, electrically
driven azimuthing stern thruster, providing
propulsion and manoeuvring. This single shaft
set-up, which comes from commercial vessels,
increases eiciency and saves fuel. An electrical
generator/motor can also power the yacht’s
entire hotel load or drive the main propeller, and
there is a third option to run on batteries alone.
“The biggest advantage is the fuel saving, up to
30 per cent,” says Schouten.

Feadship stirred up wake when it marketed

Savannah as the first hybrid yacht, with fellow

builders pointing to their own previous

achievements. Royal Huisman’s 2009

launch of 58 metre Ethereal was ahead

of its time in the hybrid game. She

uses only a fraction of the energ y of comparable

yachts and has a focus on eiciency in everything

from thicker hull insulation to electrochromic

glass, which controls solar energ y transmittance

and thereby interior temperature.

There’s another hybrid power benefit worth

mentioning: peace and quiet. Heesen

is promoting silence as “the ultimate luxury”

on its 50 metre Project Nova, its first Fast

Displacement Hull Form yacht with hybrid

propulsion, while Wider Yachts’ diesel electric

powered 150 can be self-suicient on batteries

for eight hours. “Technology has moved a long

way since Ethereal,” says her naval architect

Ron Holland. “It’s getting better and cheaper.

As these technologies continue to improve and

develop, it will become the norm.”

Hybrid is still more expensive to install than

traditional propulsion, but “you can earn that

back in fuel savings and maintenance savings on

generators”, says Schouten. De Voogt discusses

it on all projects, with about a 50 per cent opt-in

rate. “We see hybrid power as becoming the

new standard. Next, we are looking at gas

turbine generators, which have lower emissions,

maintenance and vibrations.” Royal Huisman,

meanwhile, is devoting R&D time to an

all-electric sailing yacht, with all systems

from propulsion to sail handling

relying on electrical energ y.

The caveat for hybrid truly becoming the new

normal? Yacht owners need to be on board.

Holland says the single engine, single prop

set-up is “the best option for fuel savings”

but some clients simply don’t care. “Everything

we do is client influenced,” he says. “If the

clients aren’t enthusiastic, it’s not

going to happen.”

The hybrid hype

Is diesel electric propulsion an eco-friendly trend or the

new normal in superyacht engine rooms, asks Risa Merl

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