In-depth|regulations
First application of new steel plate
Ground-breaking corrosion-resistant steel plate for oil cargo tanks will find
its first ever application before the year is out.
F
ive years of research prove that the In current vessels, the bottom plate of the cargo oil tank due to the effects of hydrogen
material ‘JFE-Steel for Ship Inside cargo oil tank is covered with a corrosion- sulfide. As corrosion spreads, it may reduce
Protection - for Oil Tankers’ (JFE- resistant membrane, but pitting occurs when the strength of the hull structure, too.
SIPTM-OT) limits deterioration of crude oil the membrane gets chipped. It corrodes up to MOL said it believed adopting this new
cargo tanks, according to Mitsui OSK Lines, about 4mm annually and if no action is taken, corrosion-resistant material offers economic
Ltd, and the shipping line is about to apply this poses a risk to safety. General corrosion and safety benefits. In addition, ‘it helps to
the material to a ship for the first time. will occur at the rear of the upper plate in the reduce CO emissions’. NA
2
The new corrosion-resistant steel plate,
developed by MOL in collaboration with
JFE Steel Corp (JFE), is set to feature on the
bottom and upper plates of the cargo oil tanks
of an MOL-operated very large crude carrier
PROVEN RESULTS
(VLCC) to be launched in November 2008.
While the International Maritime
Organization (IMO) has been discussing
FOR RUDDER
ways to improve corrosion protection by
painting inside the cargo tanks of crude
oil tankers, Japan has promoted the use of
corrosion-resistant steel as well as painting.
BEARINGS
According to MOL, the new material
combines several particular elements,
Reliability, proven performance and superior customer service have made Thordon the logical
choice in pollution free rudder bearings for over 30 years. With over 4,000 rudder bearings
significantly reducing corrosion by slowing
installed, Thordon self lubricating SXL pintle, stock and carrier disc bearings are guaranteed for
down pitting to one fifth of the level seen
15 years in newbuilds and twice the life of the replaced bearing in conversions (to a max. of 10
with conventional steel. It shows excellent
years). Supported by a worldwide distribution network, Thordon rudder bearings, as well as steer-
corrosion-resistance, even for general
ing linkage bearings and stock seals, are recognized internationally as the proven choice for value
corrosion, which occurs on the rear side of
and guaranteed performance.
the tank’s upper plate.
The material has the same weldability and
machining performance as conventional steel
plates used in the hull structure, while at the
same time reducing maintenance work in
drydock.
Tel: +1 905 335 1440
E-mail:
feedback@thordonbearings.com
www.thordonbearings.com
Pitting corrosion mechanism of crude oil
tanker’s cargo tank bottom plate.
Visit us at
stand N-5
The Naval Architect March 2008 19
NA Mar 08 -
p19.indd 19 10/03/2008 11:59:07
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