Oct 3, 2026Green Retrofit
CII Rating Explained: How Shipowners Can Improve Their Rating in 2026
The IMO Carbon Intensity Indicator tightens every year - the 2026 reduction factor is 11%. How CII is rated A-E and practical measures shipowners can take.
The Carbon Intensity Indicator (CII) is the IMO's operating-efficiency score for ships over 5,000 GT. It measures grams of CO₂ per cargo-carrying capacity per nautical mile — in plain words: how much carbon your ship emits to move one tonne of cargo one mile.
Every year each ship receives a rating from A to E. Ships rated D for three consecutive years, or E in a single year, must submit a corrective action plan.
The Rating Gets Harder Every Year
The required CII value tightens against the 2019 baseline by a fixed reduction factor: 5% in 2023, 7% in 2024, 9% in 2025 and 11% in 2026.
From 2027 onward the IMO review may tighten the trajectory further. A ship that was rated B in 2023 can slip to C or D in 2026 with no operational change at all — this is the trap many owners are now discovering at charter renewal and S&P inspections.
What Actually Moves the CII Needle
CII is calculated from fuel consumed and distance travelled. Improvement options fall into three families:
1. Cut fuel consumption (technical).
Energy Saving Devices (ESD): pre-swirl stators, semi-ducts and hub vortex reduction fins deliver roughly 3–10% fuel saving; installation during docking takes about 4–5 days
Propeller polishing, hull coating and cleaning schedules
Main engine optimization, shaft generator systems
2. Cut fuel consumption (operational).
Speed optimization and weather routing
Just-in-time arrival supported by port calls
3. Change the energy source.
Shore power at berth (reduces in-port fuel, improving overall intensity)
Alternative fuels and battery-hybrid systems for specific trades
A Practical 2026 Action Plan for a Mid-age Fleet
1. Run the numbers first. Collect fleet data and compute current EEXI and CII per ship; identify which vessels will be D/E in 2026 (many suppliers offer this assessment free of charge — SP MARINE TECH does).
2. Fix the cheapest points first. Hull/propeller condition and voyage optimization often yield immediate CII points.
3. Plan an ESD retrofit at the next docking. A pre-swirl stator or hub fins installed during scheduled docking adds days, not months, and pays back through fuel savings.
4. Watch the charter market. From 2026, CII ratings increasingly affect hire rates and buyer interest — a documented improvement plan protects asset value.
FAQ
What is the difference between EEXI and CII?
EEXI is a one-time technical measure of a ship's design efficiency (attained vs required), certified in 2023. CII is an annual operating measure with tightening targets — a ship can pass EEXI and still get a poor CII rating if operated inefficiently.
Do energy saving devices really work?
High-quality ESDs — pre-swirl stators, semi-ducts and hub vortex fins — typically deliver 3–10% fuel savings depending on hull form and operating profile. Reputable suppliers validate designs with CFD and support installation during docking.
Can CII rating affect ship sale price?
Yes. Buyers and charterers increasingly screen CII ratings; E-rated ships face charter restrictions and corrective plan requirements, which translates into lower asset value.
Want to know your fleet's 2026 CII outlook? SP MARINE TECH provides EEXI/CII assessment and ESD retrofit solutions (pre-swirl stator, semi-duct, hub fins). Request a Free Assessment →