THE hulls of the first two ships of CMA CGM's US$1.2
billion order for nine 22,500 TEU liquefied natural gas-powered containerships will be the first to feature a vertical stem design for
their "bulbless" bows as the French carrier commits its future to
slow-steaming.
These giant ships that are under
construction at Hudong Zhonghua Shipyard in China will be among the world's
largest box ships afloat and the first to extend to 24 containers across the
weather deck.
For decades containerships have
featured a protruding bulb shape at the bow but the new tugboat-like design
could become the new norm on liner trades where lower unit costs have won out
over fast transit times, reported The Loadstar, UK.
The bulbous bow works by creating an
artificial wave, modifying the water flow around the hull, which reduces drag
and raises speed and fuel efficiency. Studies have put the fuel efficiency gain
at up to 15 per cent at near full speed.
However, consultant Alphaliner
notes that the advantages of a bulbous bow containership - more complex and
therefore more expensive - have waned with the advent of slow-steaming in the
past decade, causing the fuel efficiency percentage gain to decrease
significantly.
Moreover, vessels that sail at less
than full draught - with backloads of empty containers, for example - also see
the advantages of a bulbous bow eroded.
This has prompted the retrofitting
of replacement bows, designed specifically to be more efficient at slower
speeds, to a number of container vessels over the past few years.
Source : HKSG.
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