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August 12, 2002
MOL Will Use Corrosion-Resistant NAC5 Steel
on Upper Deck of Very Large Crude oil Carriers
TOKYO -- Mitsui O.S.K. Lines, Ltd. (President,
Kunio Suzuki) today announced that its newest
crude oil tankers, to be launched in 2003,
will feature NKK Anti-Corrosion No.5 (NAC5)
steel on their upper deck. The new material,
developed by NKK Corp., will ensure longer
life for the tankersf upper decks and protect the marine environment
by reducing the risk of oil leakage
even
after many years of service.
The undersides of crude oil tankersf upper
decks are highly susceptible to corrosion caused by
high temperatures and humidity. As a result,
tankers made of conventional steel have a
service life of only about 20 years. MOL
and NKK estimate that the use of NAC5 will
extend the service life of the vessels by about five years, thanks to the materialfs
improved corrosion resistance.
The International Maritime Organization (IMO)
and other groups have shown growing concern
about corrosion on the undersides of upper
decks of crude oil tankers, and there have
been calls for more stringent inspection
of these areas of the vessels. Whatfs more,
in recent years there have been several incidents
in which aging tankers have leaked oil into
Japanfs coastal waters. To address the corrosion
problem, Nippon Kaiji Kyokai (NK) has established a stricter
inspection program including measurement
of steel plate thickness. If excessive
corrosion
is found to have reduced the strength
of
the hull, ship owners will have to
reinforce
the weakened plates.
In addition to the use of NAC5, two new crude
oil tankers under construction at NKK will
also use the AX-BOW bow design applied to
the Cape-size bulk carrier Kohyohsan, which was awarded Ship of the Year for 2001 by The
Society of Naval Architects of Japan. The
AX-BOW design improves ship propulsion in
heavy seas and reduces fuel consumption.
Further, the ships will have aerodynamically designed superstructures
to reduce wind resistance.
MOL ensures vessel safety and enhances protection
of the environment.
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