A NEW TAKE
ON ANCIENT TECH
In the last few years, the maritime media has been full of articles about the rise of robot
ships. But the future face of the shipping industry could be very different, with sail power
staging a remarkable comeback…
FINLANDS SJÖFART J SUOMEN MERENKULKU 77
As shipowners struggle to comply with increas-ingly
strict environmental requirements, a
growing number of operators are embracing the
use of wind propulsion technology to cut their
carbon footprint.
The progress was recognised last month with the
classifi cation society DNV GL giving its fi rst design type
approval certifi cate for an auxiliary wind propulsion
system: Norsepower’s 30m by 5m Rotor Sail, two of which
have been installed onboard the 109,640 dwt oil LR2
product tanker Maersk Pelican in a trial backed by the UK
government.
The Norsepower Rotor Sail is a modernised version of
the Flettner rotor, a spinning cylinder that uses the
Magnus effect to generate an aerodynamic force to propel
ships. First trialled on a ship in the 1920s, the system can
deliver fuel and emissions savings ranging between 7% and
20%. The system has also been installed on the 57,565gt
Finnish-fl agged ferry Viking Grace.
There are now six vessels with commercial rotor
installations, including the 63,233dwt geared bulker Afros,
with four moveable Anemoi rotors, the ro-ro Estraden
retrofi tted with two rotors and in regular operation
between Rotterdam and Hull, and the general cargoship
Fehn Pollux, with a single bow-mounted rotor.
These fi ve vessels follow in the footsteps of the fi rst
modern Flettner rotor-fi tted vessel, Enercon’s E-ship 1,
which has been in operation since 2009.
The Rotor Sail, or Fletter rotor, is just one of an
increasingly wide range of systems coming onto the
market. Other technologies include:
A
• soft sail – both traditional sail and new designs, such as
DynaRig, originally developed in the 1960s
• hard sail – wingsails and foils. Some rigs have solar
panels for added ancillary power generation
• suction wings (Ventifoil, Turbosail) – non-rotating wing
with vents and internal fan (or other device) that use
boundary layer suction for maximum effect
• kites – dynamic or passive kites off the bow of the vessel
to assist propulsion or to generate a mixture of thrust and
electrical energy
• turbines – using marine adapted wind turbines to either
generate electrical energy or a combination of electrical
energy and thrust
• hull form – the redesign of ship’s hulls to capture the
power of the wind to generate thrust
The technological advances, coupled with the environmen-tal,
economic and regulatory pressures, are leading a
growing number of shipping operators to consider their
use.
E Two Norsepower Rotor Sails are being
trialled by Maersk Pelican.
G The bulk carrier Afros has been fi tted
with Anemoi’s Flettner Rotor system.
The
Ecoliner
wind-powered
cargoship
concept.