HANSA 02-2023

SCHIFFSTECHNIK | SHIP TECHNOLOGY
Weather routing can be used to extend a ships »life« at certain score before downgrading
going to be successful in terms of CII,«
says research and innovation manager
Roberto Vettor.
The sailing speed and CII are also only
weakly correlated, since reduced speed
means reduced power and consumption,
but also reduced distance covered. A
much stronger correlation can be found
when looking at the sailing time. So, not
an efficient hull, but an efficient voyage
and not slow steaming as standalone
measure but integrated in a wider plan,
eliminating the wasted time, can lead to a
better score, according to Vettor’s data.
»A unidirectional approach may not
lead to the desired result. It is a combination
of factors, efficiency of hull and
propulsion system, sailing speed, time
spent in port or at anchorage, consumption
for boilers and auxiliaries,«
says Roberto Vettor, Senior R&I Manager,
Napa. He also stresses that crew and
operator must be proactive. »They have
to plan the schedule and the route, monitor
the voyage and reduce idling time.«
Napa also looked at the impact of
weather routing on the CII. The company
analyzed over 1,400 voyages of 90 bulk
carriers (30 Handysize, 30 Panamax, 30
Capesize) in 2021. The routes were analyzed
and CIIs for the vessels calculated
accordingly. The routes were then optimized
keeping the same arrival time and
using the forecast data that would have
been available to the vessels at the time.
The average CII improvement is 6.1 % for
Handysize vessels that conduct relatively
short voyages, 5.7 % for Panamax ships
and 7.5 % for Capesize vessels that
usually sail longer distances where the
impact of weather routing is higher.
»We found that by using weather routing,
a ships life in one CII grade could be
extended by two to three years before being
downgraded. This can help to postpone
more expensive interventions to improve
the technical performance of the ship,«
says Vettor. One could say that bad weather
and idling are both poison for the CII.
Predicting the CII
So, is a vessel’s CII score predictable after
all? »If you are aware, you are halfway to
the solution,« says Vettor. »If we know
what the score will be at the end of the
year, we can plan the right actions or – if
we are already in a good position – enjoy
more flexibility in the operations.«
Predicting and managing the CII is especially
important in charter parties
where the owner responsible for his
vessels’ rating is not operating them himself.
He has to rely on the charterer to operate
his assets as efficient as possible to
maintain a good score.
Bimco, the world’s largest shipping association,
has therefore adopted a standard
»CII clause« for charter parties to
help the industry implement the requirements
set by the IMO. The key point is
that the clause transfers the responsibility
for compliance with the CII Regulations
from the owner to the charterer. The
charterer has to operate and employ the
vessel in a manner consistent with the CII
regulations. And he has to operate and
employ the vessel in a manner which will
not permit the »C/P Attained CII« – i.e.
the vessel’s CII attained at the start of the
year or the delivery date if this was in the
middle of a year – to exceed the »Agreed
CII«. (i.e. the CII value which the parties
agree in the clause will be met).
»The CII agreed between owner and
charterer is measured in gCO 2
/dwt*nm.
The projected CII is an extrapolated
value until the end of the year or the
charter period. This means that an accurate
and easy tool for projection is
needed«, says sales manager Ossi Mettälä.
It is recommended that the agreed CII
is less than the one required by IMO,
middle level or a rating grade C, getting
stricter every year. If the projected CII
deviates from the agreed CII, the owner
can ask the charterer to provide a plan to
improve performance. Overall, cooperation
between parties is encouraged to
identify potential improvement areas.
Bimco also mentions voyage optimization
and active voyage monitoring to
help the parties.
»Vessels operate in a complex multidomain
environment interfacing with
sea and weather, business aspects and
technical aspects. The common nominator
for all these parameters is the
vessel,« says Mettälä. »Understanding
the ship helps to draw conclusions between
costs and efforts. At the core of the
continuous improvement cycle is reviewing
the impact of decisions made. The
same applies to CII.«
Cooperation between the owner and
the charterer requires a common and reliable
platform to predict the performance
until the end of the year or charter
period. Napa’s CII Simulator was developed
to assist the parties for keeping the
vessel’s carbon intensity under the agreed
level. All known future voyages can be included
as well as dates for underwater
hull cleaning to calculate the CII at the
end of the year.
»Routing should be more than just
safety. Weather routing is an integral part
of reducing emissions. Taking weather
routing from good to great requires more
than human experience. The amount of
parameters is countless, most affecting
the voyage KPIs differently. Optimizing
for profit, CII or fuel consumption might
yield very different results. Understanding
the sensitivity of the outcome to
the different decisions is valuable,« says
Mettälä.
What to do now? All vessels should be
monitored for their fuel performance
voyage by voyage, the experts agree. Before
applying the CII clauses for charter
parties, the owner needs to know the
realistic CII rating for a particular vessel
to be compliant. »And then you need to
focus on energy efficient operations now
immediately,« says Mettälä.
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HANSA – International Maritime Journal 02 | 2023
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