Page 34 - 2022 - Q4 - Minerva in Focus

MARINE TECHNOLOGY Water Ballast Tank Coatings:
Challenges, requirements
& maintenance
“ Ballast water tanks are used to maintain
The most efficient way to
preserve the corrosion
prevention system of water
ballast tanks is to repair
any defects found during
in-service inspections.
” Discussions about the need for improved
by Christos Marougas,
Technical Services and Support Manager,
Jotun Hellas Ltd.
34 MINERVA IN FOCUS – ISSUE 22 / Q4 2022
Tailor-made protection
not an easy task. Good pretreatment and for optimum hull efficiency
the stability of a vessel and are a major
achieving even coating application at the
contributor to its strength. A ship can
correct film thickness are often tricky be-
only be at load and sailing when it is suf-
cause access is not easy, the conditions are
ficiently sturdy and stable, which is also humid, and the light is poor. As the work is
required for the ship to be able to with-
costly and the conditions are challenging
stand certain types of damage. When the and dirty, there is perhaps a tendency to
ship is safe, so are its cargo, passengers, “forget” the ballast tanks - “out of sight is out
and the marine environment around it
of mind.” It is, therefore, not usual for vessels
because there will be no pollution (such that are well protected on the outside to be
as oil or other liquid cargo leakages) candidates for the rapid progression of heavy
from a damaged (or sunken) ship.
corrosion inside. If surface preparation is
the building stage or left unattended during
poor or the steel is insufficiently protected at
service, corrosion will start at the recognized
safety at sea and better environmental pro-
weak spots, especially the sharp edges and
tection led to the adoption of MSC.215(82),
welding seams, which are areas subjected
the IMO’s PSPC regulation for ballast water
to intermittent wet and dry
cycles of aerated water. This
places extreme demands on
corrosion control methods. If
corrosion is allowed to take
hold, the steel will have to
be renewed, or if beyond
repair, the vessel will then be
scrapped.
Remedial work in any area
of a vessel can be expensive
and time consuming. Ballast
tanks are of high structural
importance to the vessel but
can be enormously costly to
repair, primarily because of
their difficult access. As a rule,
tanks. All coatings applied to ballast water putting a ship into a repair shipyard to recoat Improved fuel efficiency Reliable performance Environmentally conscious
tanks of new ships over 500 gross tons (GT) its ballast tanks to their original standard will
contracted after 1 July 2008 must comply cost at least twice as much as installing a sol- Three silyl methacrylate formulations, with microZone™ technology, each one tailored to your operational profile.
with this regulation. The objective of this id system on a newbuilding. The newbuilding
standard is to ensure that the coating sys- stage offers the ideal opportunity to invest in Maximise fuel efficiency and ROI while minimizing VOC content and GHG emissions.
tem of ballast tanks has a service life of at the long-term protection of ballast tanks and
least 15 years. avoid the high cost of eventual remedial work
The tanks are highly humid and often reach caused by poor preparation and ineffective
high temperatures, and as they are partial- coating protection. Maintaining the corrosion
ly filled with seawater, sacrificial anodes prevention system should be included in the
cannot assist in corrosion prevention in overall ship’s maintenance scheme.
not immersed areas. These compartments The most efficient way to preserve the cor- Bring your average speed loss down to just 2% *
could simply be described as “corrosion rosion prevention system of water ballast
chambers,” and there is no tougher testing tanks is to repair any defects found during
ground for paint. in-service inspections.
Repairing ballast tanks is undoubtedly
* expected on average over a 60-month service interval, based on ISO 19030
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