Ship-type-specific CII for crude tankers (VLCC, Suezmax, Aframax, Panamax).
Formula
$$ \text{CII}\text{attained} = \frac{\sum_j F_j \cdot C{f,j} \cdot 10^6}{\text{DWT} \cdot D} $$
$$ \text{CII}_\text{required} = 5247 \cdot \text{DWT}^{-0.610} \cdot (1 - Z) $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $F_j$ | Mass of fuel $j$ | t | IMO DCS |
| $C_{f,j}$ | CO₂ factor of fuel $j$ | t CO₂ / t fuel | MEPC.364(79) |
| $DWT$ | Deadweight tonnage | t | tonnage certificate |
| $D$ | Distance | nm | IMO DCS |
| $Z$ | Annual reduction - 5/7/9/11 % | fraction | MEPC.338(76) |
Rating boundaries (MEPC.339(76) tanker row): d1=0.82, d2=0.93, d3=1.08, d4=1.28.
Sources
- IMO Resolution MEPC.337/338/339(76).
- MEPC.364(79) - Cf factors.