In-depth | Sail-aSSiSted propulSion
Cargo ships sail into the 21st Century
Concerns over climate change and fuel security suggest that ships propelled
by wind might once again be needed. 21st Century sailing ships are likely
to have motors too; they will either be motor-assisted sailing ships or wind-
assisted motor ships, George Marsh reports.
D
avid Surplus is a proponent of
the former. He fervently believes
that sailing cargo ships will stage
a comeback and is managing director of a
firm, B9 Shipping Ltd, dedicated to making
it happen.
The ships envisaged are 3000tonnes
deadweight steel-hulled cargo vessels
sized to serve islands and island states that
require regular service, but whose cargo
volumes are too low to interest conventional
shippers. Surplus says the ships will rely
on conventional soft sails for 60% of their
motive power and, for the other 40%, on
engines powered by biogas derived from
waste by anaerobic digestion. He envisages
scores of such craft trading by 2050, replacing
some of the ten thousand coastal ships of this Historical image of Flettner’s rotor ship (Credit: uS library of Congress).
size currently operating around the world,
thereby helping to reduce shipping sector
emissions, which are greater than those of superstructure are located aft. strains and gear wear. General cargo or up
aviation but have so far escaped the same The project benefits from funding to 16 containers were carried in the main
level of critical scrutiny. under the low-carbon shipping research hold, a forward hold was refrigerated and
B9 Shipping, an offshoot of independent programme ‘Low Carbon Shipping - a passengers were accommodated aft.
wind farm operator B9 Energy, has attracted Systems Approach’, which has received £1.7 Subsequently operating for a further
formidable working partners including: million (US$2.6 million) from the UK’s year as a feeder vessel between West Indian
Rolls-Royce for the methane-burning Engineering and Physical Sciences Research islands, Atlantic Clipper altogether clocked
engines; Corus to supply the vessel’s steel Council (EPSRC). A demonstrator vessel up some 100,000nm and carried thousands
plates, recycled from steel scrap and should be launched in 2012, at about the of tonnes of cargo. Allen, who believes that
delivered as flat-pack constructional kits by time a number of UK biomass power stations modern materials have transformed the
Jim Moore Steel Kits; and naval architect are due to open. This is significant because prospects for sailing ships, has since advised
Humphreys Yacht Design (HYD), which one of the cargoes proposed for the ships is B9 in developing its own sailing concept.
was largely responsible for Dame Ellen imported biomass.
MacArthur’s record breaking Open 60 A precursor to B9’s concept was Atlantic revolutionary approach
Kingfisher and a Global Challenge fleet of Clipper, a 32.3m loa steel-hulled motor/sail Within the ‘wind assist’ school, a more
12 identical steel-hulled yachts. HYD has craft that marine engineer Jeff Allen built revolutionary approach, literally, is to exploit
drawn an easily driven hull carrying three and traded with for two years during the the effect whereby a vertically mounted
masts of equal height, each having four 1980s between the UK and the Caribbean. cylinder, when rapidly rotated, exerts a force
sails on yards which can be angled so that Making the journey every six weeks, winter at approximately right angles to the wind. On
the ship can sail with the wind anywhere and summer, the 400tonnes craft averaged the side of the cylinder moving against the
from dead aft to forward of the beam. To 8.5kts, saving an estimated £11,000 in wind, the air piles up and exerts pressure. On
minimise crewing requirements, spars are operating costs every trip compared with the opposite side, suction is created, exerting
moved and sails furled electrically, though an all-motor vessel. The fore and aft rig a pull. Suction accounts for about seven
without the complex automation seen in set on twin 30.48m masts provided the eighths of the total motive force, pressure for
high-tech sailing superyachts such as Tom main propulsion and helped stabilise vessel the remaining one eighth.
Perkins’ Maltese Falcon. A deckhouse and motion in a seaway, reducing structural This phenomenon, dubbed ‘the Magnus
20 Ship & Boat International March/April 2010
Leaves others in its wake
SBI_MarApr10_p20-21-22.indd 20 26/02/2010 12:21:12
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