# CII Rating for Ships: Where Efficiency Work Lands

> A CII rating is the IMO's annual A-E grade for a ship's carbon intensity. See which efficiency work a low band triggers at the port call, and who signs it off.

URL: https://vesselreach.si/blog/cii-ratings-why-operators-buy-efficiency-help | Published: 2026-11-01 | Updated: 2026-11-02 | Guide | Topic: Carrier service and surcharge changes

## In short

A CII rating is the IMO's annual A to E grade for a ship's carbon intensity, and a low band is a buying signal for efficiency work. Operators with a poor grade spend at the port call on hull cleaning, propeller polishing, fuel planning, retrofits and monitoring hardware, approved by technical and purchasing superintendents at the managing company.

## Key takeaways

- A CII rating is annual and relative, so a ship can drop a band within a year and start buying efficiency help.
- A low band triggers hull cleaning, propeller polishing, fuel switches, retrofit installation and monitoring hardware at the port call.
- The technical superintendent owns the specification and the purchasing superintendent places the order for efficiency work.
- Efficiency work competes with cargo operations for the same hours alongside, so approach the managing company before the vessel berths.

## At a glance

- **What: What is the CII?** The Carbon Intensity Indicator is an IMO measure of a ship's carbon emissions per unit of transport work, applied annually and graded into bands, alongside the one-off EEXI design index. ([Institutional Repository Hellanicus](http://hdl.handle.net/11610/25754))
- **Who: Who is financing efficiency technology on ships?** The Global Centre for Maritime Decarbonisation, AIM Horizon Investments and Eastern Pacific Shipping financed two wind-assisted propulsion projects through the Fund for Energy Efficiency Technologies in October 2026. ([MarineLink](https://www.marinelink.com/news/fund-energy-efficiency-technologies-543793))
- **Where: Where is efficiency work being planned?** Onboard and at the port call: wind-assisted propulsion installations, hull and propeller work, and power system optimisation all require physical attendance at a port or yard. ([Seatrade Maritime News](https://www.seatrade-maritime.com/sustainability/eastern-pacific-shipping-first-to-tap-gcmd-efficiency-fund))
- **When: When did the efficiency fund make its first deployment?** The financing for the first two wind-assisted propulsion projects was announced in October 2026, marking the fund's first deployment since launch. ([MarineLink](https://www.marinelink.com/news/fund-energy-efficiency-technologies-543793))
- **Why: Why are operators optimising ship power systems?** A 2024 IEEE paper described a control strategy that optimises hybrid shipboard power while ensuring compliance with CII limits, because the annual rating constrains how a ship is operated. ([IEEE Transactions on Transportation Electrification](https://doi.org/10.1109/tte.2024.3471192))
- **How: How can a voyage be adjusted for CII compliance?** A 2025 routing framework applies dynamic programming with weather data and a cumulative compliance probability, letting a single voyage be adjusted before the annual CII score is settled. ([International Journal of Naval Architecture and Ocean Engineering (Elsevier BV)](https://doi.org/10.1016/j.ijnaoe.2025.100670))

A CII rating is an annual grade from A to E that the IMO gives a ship for its carbon intensity, and operators with low grades are actively buying efficiency help to lift them. For service providers, that grade is a buying signal you can read before the vessel reaches your port.

## What the CII rating actually measures

It measures how much carbon a ship emits per unit of transport work over a calendar year, then places it in a band against ships of similar type and size. A 2023 study lodged in the Hellanicus repository examined the two IMO indices behind this, CII (the Carbon Intensity Indicator, an annual measure of carbon emitted per unit of transport work) and EEXI (the Energy Efficiency Existing Ship Index, a one-off design check on a ship's efficiency), and the strategic response they force on shipping companies ([Hellanicus](http://hdl.handle.net/11610/25754)).

Two practical consequences follow. The grade is annual, so a ship can drift down a band within a year. And it is relative, so a vessel's rating depends partly on how its peers perform.

## Why a rating band changes what operators buy

A poor band creates pressure on the technical and commercial sides of a ship manager at the same time, and both spend money at the port call.

- **Technical managers** look at hull and propeller condition, machinery efficiency and voyage speed choices.
- **Commercial and chartering teams** care because charterers increasingly ask about ratings before fixing.
- **Owners and fleet directors** weigh retrofits against the cost of staying in a low band.

Research on routing shows the rating is manageable within a year rather than fixed at the start of it. A 2025 study in the International Journal of Naval Architecture and Ocean Engineering proposed a CII-oriented routing framework built on cumulative compliance probability, integrating weather data and dynamic programming so a single voyage can be adjusted before the annual score is set ([Elsevier](https://doi.org/10.1016/j.ijnaoe.2025.100670)).

Control systems are being tuned the same way. A 2024 paper in IEEE Transactions on Transportation Electrification described a model predictive control strategy for hybrid shipboard power systems that optimises speed while ensuring compliance with CII limits ([IEEE](https://doi.org/10.1109/tte.2024.3471192)).

## Efficiency projects now have a financing route

Wind-assisted propulsion and similar hardware used to stall on payback arguments. In October 2026 the Global Centre for Maritime Decarbonisation, AIM Horizon Investments and Eastern Pacific Shipping announced financing for two wind-assisted propulsion projects through the Fund for Energy Efficiency Technologies, the fund's first deployment ([MarineLink](https://www.marinelink.com/news/fund-energy-efficiency-technologies-543793)). Seatrade Maritime reported that the fund uses measured fuel savings to determine repayments ([Seatrade Maritime News](https://www.seatrade-maritime.com/sustainability/eastern-pacific-shipping-first-to-tap-gcmd-efficiency-fund)).

That matters to suppliers because measured savings mean measured installation, commissioning and service work. A wind-assisted unit needs structural checks, deck work, cabling and periodic inspection, and those tasks land at ports and yards, not at head office.

Digital efficiency work is moving in the same direction. China Merchants Energy Shipping and RINA signed an MoU in October 2026 covering maritime safety, digitalisation, AI and emissions management ([Marine Insight](https://www.marineinsight.com/china-merchants-energy-shipping-partners-with-rina-to-explore-ai-driven-ship-operations/?utm_source=rss&utm_medium=rss&utm_campaign=china-merchants-energy-shipping-partners-with-rina-to-explore-ai-driven-ship-operations)). Operators pursuing that route still need sensors fitted, data cables run and systems commissioned alongside.

## Where the work lands for each type of provider

The rating itself is a management problem, but each band movement creates physical tasks at the port call.

ProviderWork a low CII band tends to trigger

Hull cleaning and propeller polishingFouling removal before the next reporting period, booked around scheduled calls
Bunker suppliersFuel switches, blends and stem planning tied to speed and consumption changes
Ship repair yardsRetrofit installation, structural work for wind-assisted units, machinery overhauls
Ship chandlersSpares and consumables for efficiency equipment, filters, monitoring hardware
Port agentsCoordinating contractors, permits and shore access for efficiency works during a call

The [sales playbook for hull cleaning and propeller polishing](https://vesselreach.si/blog/hull-cleaning-and-propeller-polishing-a-sales-playbook) covers [how to time that conversation](https://vesselreach.si/blog/ship-repair-yards-turn-vessel-movements-into-sales) around a port call rather than a calendar year.

## Who signs off efficiency spending

Efficiency purchases rarely sit with one person. On the ship manager's side, the technical superintendent owns the specification and the purchasing superintendent owns the order, a split covered in [who owns what at a port call](https://vesselreach.si/blog/technical-superintendent-who-owns-what-at-a-port-call). Above them, fleet and technical directors approve retrofit spend, and commercial managers weigh charterer expectations.

That means a supplier pitching efficiency work needs the right name first. Sending a hull cleaning proposal to a crewing contact wastes the call and the goodwill.

## Timing the approach before the vessel arrives

Efficiency work competes with cargo operations for the same hours alongside. Approach too late and the window has closed.

1. Identify vessels due at your ports whose operators are running efficiency programmes, using ETA (Estimated Time of Arrival, the expected time a ship reaches port) and recent port-call history.
2. Find the technical or purchasing superintendent at the managing company, not the charterer.
3. Lead with the measurable outcome the buyer is already funding, such as fouling removal or a retrofit installation slot.
4. Follow up across email, WhatsApp and phone before the arrival window narrows.

Waiting for the ship to berth leaves no time to scope, quote and get approval. Reading [why days before port matter](https://vesselreach.si/blog/vessel-arrival-timing-why-days-before-port-matter) explains the lead time in more detail.

## How VesselReach helps

VesselReach turns vessel movements at your chosen ports into conversations with the people who approve efficiency work.

- **Vessel intelligence** shows ships near your ports and those scheduled or expected to arrive, which means you can approach a technical superintendent before the vessel berths and the window closes.
- **AI company targeting and decision-maker discovery** identify the managing company behind each vessel and the operations, technical, procurement and fleet roles that sign off efficiency spend, so your proposal reaches the buyer rather than a general inbox.
- **Staged outreach across email, WhatsApp and phone, with automated follow-ups**, keeps the conversation moving through the weeks before arrival.

Book a VesselReach demo to see the workflow on your own ports.

## Frequently asked questions

### What is a CII rating in shipping?

A CII rating is an annual grade from A to E that the IMO gives a ship for its carbon intensity. It measures how much carbon a ship emits per unit of transport work over a calendar year, then places the ship in a band against vessels of similar type and size. ([Institutional Repository Hellanicus](http://hdl.handle.net/11610/25754))

### What is a good CII rating for a ship?

Ratings run from A to E, and A to C is generally treated as compliant while D or E signals a ship that needs improvement. The grade is annual and relative to similar ships, so a vessel can move bands within a year. ([Institutional Repository Hellanicus](http://hdl.handle.net/11610/25754))

### How is the CII rating calculated?

The CII rating compares carbon emitted per unit of transport work over a calendar year against ships of similar type and size. Because the band is relative, a vessel's grade depends partly on how its peers perform, and it is reset annually rather than fixed per voyage. ([Institutional Repository Hellanicus](http://hdl.handle.net/11610/25754))

### Can a ship improve its CII rating within a single year?

Yes. A 2025 study in the International Journal of Naval Architecture and Ocean Engineering proposed CII-oriented routing that adjusts individual voyages using weather data and cumulative compliance probability, because the indicator is annual rather than fixed per voyage. ([International Journal of Naval Architecture and Ocean Engineering (Elsevier BV)](https://doi.org/10.1016/j.ijnaoe.2025.100670))

### How do efficiency retrofits get financed now?

In October 2026 the Fund for Energy Efficiency Technologies financed its first two wind-assisted propulsion projects with Eastern Pacific Shipping. Seatrade Maritime reported that repayments are determined by measured fuel savings, which ties finance to verified performance. ([Seatrade Maritime News](https://www.seatrade-maritime.com/sustainability/eastern-pacific-shipping-first-to-tap-gcmd-efficiency-fund))

### Who should a supplier contact about efficiency work on a vessel?

Start with the technical superintendent at the managing company, who owns the specification, and the purchasing superintendent, who places the order. Fleet and technical directors approve larger retrofit spend. The charterer is usually not the buyer.

## Sources

1. [A Model Predictive Control-Based Energy Management Strategy for Secure Operations in Shipboard Power Systems](https://doi.org/10.1109/tte.2024.3471192), IEEE Transactions on Transportation Electrification, 2024-09-30
2. [Εκτίμηση επιπτώσεων και διαμόρφωση στρατηγικής ναυτιλιακών εταιρειών από την εφαρμογή των energy efficiency existing ship index και carbon intensity indicator](http://hdl.handle.net/11610/25754), Institutional Repository Hellanicus, 2023-01-01
3. [A CII-oriented ship routing framework based on probabilistic decarbonization compliance](https://doi.org/10.1016/j.ijnaoe.2025.100670), International Journal of Naval Architecture and Ocean Engineering (Elsevier BV), 2025-01-01
4. [China Merchants Energy Shipping Partners With RINA To Explore AI-Driven Ship Operations](https://www.marineinsight.com/china-merchants-energy-shipping-partners-with-rina-to-explore-ai-driven-ship-operations/?utm_source=rss&utm_medium=rss&utm_campaign=china-merchants-energy-shipping-partners-with-rina-to-explore-ai-driven-ship-operations), Marine Insight, 2026-10-13
5. [Eastern Pacific Shipping first to tap GCMD efficiency fund](https://www.seatrade-maritime.com/sustainability/eastern-pacific-shipping-first-to-tap-gcmd-efficiency-fund), Seatrade Maritime News, 2026-10-20
6. [Fund for Energy Efficiency Technologies Finances First Two Wind-Assisted Propulsion Projects](https://www.marinelink.com/news/fund-energy-efficiency-technologies-543793), MarineLink, 2026-10-20

## More on this topic

A CII rating is the annual grade the IMO gives a ship for its carbon intensity, and a low band pushes operators to buy efficiency help rather than wait. That help is physical work: hull cleaning, propeller polishing, retrofit installation, fuel planning and monitoring hardware. It lands at the port call, which is why suppliers who know a vessel is coming can pitch the technical superintendent before the ship berths. The CII rating is manageable within a year through routing and power management, so operators act early and often. Knowing which managing company sits behind each arriving vessel is the difference between a proposal that gets read and one that arrives after the window has closed.

A CII rating for ships is an annual A to E grade from the IMO, and the calculation compares carbon emitted per unit of transport work against ships of similar type and size. Because the grade is annual and relative, a vessel can slip a band within a year, which is why operators act on the CII rating scale rather than waiting. The CII rating table in this post maps each low band to the work it tends to trigger at the port call: hull cleaning, propeller polishing, retrofit installation, fuel planning and monitoring hardware. Efficiency spending is approved by technical and purchasing superintendents, so reach the managing company before the vessel berths.

Which work does a low CII band trigger at the port call? Hull cleaning and propeller polishing before the next reporting period, fuel switches and stem planning for bunker suppliers, and retrofit or machinery work for yards. Each task is booked around scheduled calls, not the calendar year.

Who approves efficiency spending on a ship? The technical superintendent owns the specification and the purchasing superintendent places the order, while fleet and technical directors approve retrofit spend. A ship chandler pitching spares or monitoring hardware should reach those roles at the managing company first.

Why approach the vessel before it berths? Efficiency work competes with cargo operations for the same hours alongside, so scoping, quoting and approval have to happen before the arrival window narrows.

A CII rating is not fixed at the start of the year. Because the grade is annual and relative to ships of similar type and size, a vessel can slip a band within twelve months, and operators respond by buying efficiency work rather than waiting for the next reporting period. That work is physical and it lands at the port call: hull cleaning, propeller polishing, retrofit installation, fuel planning and monitoring hardware. The buyer is the technical superintendent at the managing company, with the purchasing superintendent placing the order, so a supplier who identifies the right vessel and role before arrival gets the proposal read in time.

Related searches: cii rating for ships; cii rating calculation; cii rating scale; cii rating table; ship chandler; ship chandlers

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