CII 3-Year Corrective Plan Projector
After a D-for-three-years or single E rating, owners must file a SEEMP Part III plan to return to at least C. Project the annual CII trajectory required.
Current state
Current rating ratio
1.267
E (plan required now)
Target ratio (end of plan)
1.060
C boundary (ratio ≤ d₃)
Annual CII reduction needed
6.5%
Straight-line path to C by end of plan.
Approach
Annual reduction = 1 − (target_ratio × required_future / attained_current)^(1/N)
Assumes required CII tightens at the scheduled Z rate (5 % → 7 % → 9 % → 11 %). The calculator computes the straight-line attained-CII trajectory that would land at the C-band boundary at the end of the plan horizon. Realistic plans usually front-load measures (hull clean, speed optimisation) in year 1 and count on alternative-fuel trials by year 3.