How a model can help you comply with CII

We are only a few short months away from the implementation of IMO2023.  IMO2023 goes into effect on 1 January 2023 and will impact the operations of all oceangoing vessels above 400GT.

What's IM02023?

IMO2023 will require vessels to comply with regulations imposing an Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII).  

The EEXI measures CO2 emissions taking into account the vessel’s design characteristics. Vessel operators are required to assess vessel energy consumption and CO2 emissions against energy efficiency standards for the vessel type.  The CII calculates the ratio of CO2 emissions against the distance and cargo carrying load of a vessel over a year.

When a vessel is not efficient, ship owners may need to implement technical measures to adjust their vessels’ emissions to the required level.

There are several ways in which a vessel owner or operator can come into compliance with the requirements of IMO2023.  The easiest and most cost-effective method is to control the vessel’s energy consumption. This can be done in two ways:

First is by sailing the vessel at an optimal speed which will minimize vessel bunker consumption.

The second is to make sure the vessel is in a good shape. Issues like marine growth (fouling) or hull degradation will increase the resistance of the hull, and therefore negatively impact consumption.

How a model can help

We4Sea can provide you with a speed optimisation solution that minimizes bunker consumption and reduce CO2 emissions.  The We4Sea Speed Advisor module will allow you to simulate various settings like ETA, charter rate and fuel price to determine the most optimal bunker consumption for the voyage, reducing CO2 emissions and bringing the vessel into compliance.

During the voyage, the We4Sea Digital Twin model enables you to monitor the vessel speed on a current voyage and adjust the speed as necessary, considering the weather (winds and waves) and ocean currents and find the optimal speed which minimizes vessel consumption thus improving energy efficiency and resulting CII rating.

To make sure the vessel is in agood technical shape, we use our Digital Twin-based benchmarking.

In our approach, the Digital Twin represents a clean and perfectly running vessel. We continuously compare the vessel-reported consumption (which gives the Actual Performance) with the Digital Twin (which represents the Achievable Performance). As the Digital Twin already takes into account wind, waves, ocean currents, speed, and draught, any deviation can be spotted directly as inefficiencies and fuel waste.

After an intervention, such as a hull cleaning, we can directly see the effect as the Actual Performance and Achievable Performance will have a better match. Over time, the difference will start to grow as fouling and aging is a continuous process, accelerated by idling and seawater temperature. This means continuous monitoring is essential.

Are you ready for CII?

Many Shipowners seem to focus only on the reporting side of CII, where the biggest challenge may be to control the CII over time and improve it where possible.

By using We4Sea, you can not only report CII, but also control and improve a vessel's CII rating.

Also, we support in comparing similar vessel’s in your fleet to determine which vessels are meeting the IMO2023 requirements and which vessels may require remedial action such as optimising speed, as well as engine maintenance or hull cleaning to bring the vessel into compliance.

Want to know more? Just get in touch with us or send an email to, happy to answer any questions.