the coating applied and the fuel consumed the company
said. The report showed that fuel consumption was re-
duced by 10 percent on the Prem Divya, 22 percent on
the Ikuna and by five percent in five container vessels
(based on all five ships carrying a comparable load). The
report stated that if similar fuel efficiency results were
realized by all tanker and bulk cargo vessels within the
commercial fleet that, “Annual fuel oil consumption
could be reduced by roughly 16 million metric tons
(MMT) per year, fuel expenditures could be reduced by
$4.4 to $8.8 billion per year, and nearly 49 million tons
of CO2 emissions could be avoided annually.”
At a more detailed level, the report stated that the
latest generation fluoropolymer foul release coating
could offer average fuel and emissions savings of up to
nine percent.
Challenge
For some, though, such claims are always open to challenge. Critics argue that, no matter which coating is applied, a ship will naturally move through the water more
smoothly if it has been blast cleaned during drydocking.
Furthermore, they argue, the linkage between hull
smoothness and reduced emissions is tenuous: traditionally, extra smoothness was more likely to lead to
some ships being driven faster, not to fuel savings.
On the face of it, seemingly persuasive such arguments could be readily countered by observing the growing propensity for owners to operate slow steaming
policies specifically in pursuit of fuel (and consequently
emissions) savings. Again, while no one would dispute
that depending upon the fouling control system employed, a newly grit blasted or hydroblasted, freshly
coated hull will perform better than a hull at the end of
its docking cycle, the point is surely to measure how
quickly hull performance deteriorates over time in the
context of the coating systems applied.
Methods of measurement
For this reason, International Paint has been explicit in
detailing the alternative methods that have been used as
the means of establishing linkage between the fouling
control system selected and potential fuel savings.
Some common methods are as follows:
1. Directly comparing the in-service vessel performance when using one fouling control system over
its full lifetime to that of another fouling control
system over its full lifetime.
2. Directly comparing a period of time in-service
prior to dry docking with one fouling control system to the same period after the dry docking and
application of a new fouling control system. Different before and after periods can be used and in
general are much less than full in-service periods,
i.e. 12 months before a dry docking compared to
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